Search Results (379)

Graphene and carbon nanotube (CNT) membranes are promising for filtration, desalination, and water treatment, yet their performance requires the joint interpretation of their architecture, nanoconfined transport, selectivity, fouling, swelling, defects, stability, and operating conditions. Here, GCMembrane-LLM was developed as an evidence-grounded domain-specific large language model. A curated 582-paper corpus generated 12,208 cleaned membrane-specific question–answer pairs for Low-Rank Adaptation (LoRA)-based supervised fine-tuning of Llama-3.1-8B-Instruct, and retrieval-augmented generation provided article-title and page-level traceability. GCMembraneBench included 100 application-oriented questions on graphene oxide (GO) membranes, CNT membranes, GO/CNT hybrids, and cross-material reasoning. Under direct answering without retrieval context, the anonymized and shuffled automatic evaluation showed that GCMembrane-LLM achieved a mean weighted score of 4.237/5.0, exceeding Llama-3.1-8B-Instruct and Doubao-1.5-lite. A stratified 30-question blinded manual assessment showed the same ranking. The application cases further yielded membrane science conclusions: CNT-assisted GO/CNT transport should be evaluated with dispersion, interfacial compatibility, defects, and stability; GO desalination depends on swelling control, interlayer spacing, and defect suppression; and CNT high flux requires joint examination of pore diameter, entrance chemistry, hydration barriers, ion rejection, and operating conditions. GCMembrane-LLM supports source-traceable evidence organization and preliminary hypothesis formulation before experimental validation. Full article

Accurate prediction of external short-circuit (ESC) current is important for battery safety analysis and protection design, but conventional equivalent circuit models have difficulty reproducing the strongly nonlinear current evolution under ESC conditions. This study proposes a reaction-process-corrected second-order RC model for ESC current prediction, based on ESC experiments on a 37 Ah commercial NCM pouch cell at different initial SOCs. The ESC process is described by three successive stages: bottleneck control, concentration-difference control, and separator pore closure. To represent the transport-related resistance deviation during this process, an additional correction resistance R_x and a queued-charge descriptor Q are introduced into the equivalent circuit framework. A segmented closed-loop simulation strategy is then developed to update R_x and predict the ESC current. Using the 50% SOC case as an unseen validation case, the proposed model captures the main nonlinear characteristics of ESC current, including rapid initial decay, secondary rebound, and subsequent attenuation. The proposed framework improves the physical interpretability of equivalent-circuit-based ESC simulation while retaining engineering simplicity, providing a practical approach for safety-boundary assessment and protection-oriented battery system design. Full article

Carbon aerogels possess continuous three-dimensional conductive networks, hierarchical pore architectures, and tunable surface chemistry. These structural characteristics make them suitable electrode materials for alkali-metal-ion batteries. This review examines the controlled synthesis and heteroatom doping of carbon aerogels. The discussion links framework construction, electronic-structure modulation, and storage mechanism matching with their electrochemical behavior. The rational design of carbon aerogels should move beyond the simple pursuit of high specific surface area or high dopant content. Effective electrodes require the coordinated regulation of pore architecture, conductive continuity, heteroatom-doped sites, and ion-storage pathways. The current application status of carbon aerogels in alkali-metal-ion batteries is also analyzed from an industrial perspective. A mechanism-oriented and application-oriented framework is therefore required to translate carbon aerogel-based electrodes from structural optimization to a practical battery. Full article

The interlayer pores of 3D-printed concrete (3DPC) significantly weaken its macroscopic mechanical properties. In this study, the phase-field cohesive zone model (PF-CZM) is employed as a numerical tool to systematically investigate the weakening mechanisms and crack evolution behavior associated with pore characteristics, including pore size, morphology, spatial orientation, and arrangement, through single-factor numerical simulations with different pore numbers. The results demonstrate that the degradation induced by a single pore is controlled by its effective projection length in the direction perpendicular to the principal tensile stress, with horizontal flat pores being the most detrimental under the same porosity. In the multi-pore system, the connection angle between pores, rather than their spacing, is the key factor determining structural degradation, and a horizontal collinear arrangement is prone to triggering brittle fracture. Furthermore, locally aggregated small pores can form combined defects, whose strength-weakening effect surpasses that of isolated large pores, thereby triggering crack path competition and leading to asymmetrical structural failure. This study reveals the fracture mechanisms driven by complex pore configurations and provides a reference for strength prediction of 3DPC. Full article

Focused-ion-beam scanning electron microscopy (FIB-SEM) provides site-specific access to buried interfaces, particle interiors, porous electrode architectures, and localized degradation regions in energy materials. This capability is particularly valuable for rechargeable batteries, solid-state ion conductors, alkali-metal electrodes, and reactive solid–liquid interfaces, where the structures governing transport and failure are rarely exposed at a free surface. However, the preparation and imaging steps that reveal these regions may also alter them. Ion milling, environmental transfer, vacuum exposure, scanning electron microscopy (SEM), cryogenic handling, transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), energy-dispersive X-ray spectroscopy (EDS), electron energy-loss spectroscopy (EELS), and atom probe tomography (APT) can each modify local morphology, chemistry, or phase state. These effects are especially important when the intended evidence involves light elements, metastable phases, nanoscale coatings, reactive interphases, volatile species, or ion-conducting materials. This perspective develops a claim-specific framework for evaluating such results. Preparation- and imaging-induced changes are related to the material feature being interpreted and to the minimum control needed to distinguish the two origins. For porous electrodes, the relevant outputs include pore volume, connectivity, tortuosity, crack geometry, phase fraction, and active surface area. For reactive interfaces and solid electrolytes, the critical questions concern alkali-metal redistribution, surface amorphization, light-element contrast, implanted-species chemistry, and beam-induced phase formation. The discussion further compares conventional Ga-FIB, cryogenic FIB, Xe plasma FIB, low-energy Ar+ polishing, broad-ion-beam preparation, ultramicrotomy, and repeated particle-oriented FIB workflows. Reliable interpretation requires the preparation route, transfer conditions, imaging dose, analytical acquisition, and claim-specific controls to be reported together with the final microscopy result. Full article

We conducted a theoretical analysis on the diffusiophoretic motion of a dielectric droplet in a cylindrical pore in the presence of an induced diffusion potential, such as that in a NaCl electrolyte solution. The fundamental electrokinetic governing equations are solved using a patched pseudo-spectral method based on Chebyshev polynomials, coupled with a geometric mapping scheme to handle the irregular solution domain. The impact of the boundary confinement effect on droplet mobility is examined in detail. Interesting electrokinetic phenomena are found in this work, such as mobility reversal in narrow cylindrical pores with the droplet moving against the direction expected based on the classical Coulomb electrostatic law due to the strong boundary confinement effect. Moreover, “solidification phenomenon” is also found at some specific pore radius where the droplets move as rigid particles with no interior recirculating vortex flows regardless of the droplet viscosities. Corresponding critical points of ${\mathrm{R}}_{\mathrm{w}}^{\mathrm{*}}$, the ratio of droplet radius to the cylindrical radius are found where the spinning orientation on the droplet surface changes each time as it passes them. The profound boundary confinement effect, both electrostatically and hydrodynamically, is responsible for these peculiar phenomena. The results presented here have direct applications in microfluidic and nanofluidic operations as well as drug delivery applications. Full article

Freeze–thaw durability of 3D-printed engineered cementitious composites (3DP-ECC) is strongly affected by print-induced interlayer defects and anisotropy, particularly in cold regions. This study investigated Cast-ECC and Z-direction 3DP-ECC incorporating Yellow River sediment (YRS) as an equal-mass replacement for quartz sand at 0–100%. Compressive, three-point bending, and four-point bending tests, relative dynamic elastic modulus (RDME), XCT, MIP, SEM–EDS, and Weibull damage modeling were used to evaluate degradation up to 150 freshwater freeze–thaw cycles. Moderate YRS replacement (25–50%) improved particle packing, reduced visible defects, and refined the pore structure, thereby enhancing frost resistance. The R50 mixture showed the best residual performance: after 150 cycles, compressive strength decreased from 55 to 46 MPa in Cast-ECC and from 54 to 44 MPa in 3DP-ECC, corresponding to retention rates of 83.6% and 81.5%, respectively. The residual peak load in four-point bending of 3DP-ECC-R50 was 15.4% lower than that of Cast-ECC-R50, confirming the detrimental role of interlayer defects under loading perpendicular to the layers. RDME-based Weibull fitting described the overall damage evolution (R² = 0.876–0.994), while XCT, MIP, and SEM–EDS indicated that interlayer discontinuities, pore-structure evolution, and local microstructural degradation governed anisotropic deterioration. The results support durability-oriented design of YRS-based 3DP-ECC in cold regions. Full article

Reliable prediction of the factor of safety (Fs) of circular-failure soil slopes is critical to geotechnical practice. Data-driven models developed on small slope-stability datasets are, however, prone to overfitting, data leakage, and optimistic bias, which can lead to overestimated predictive performance. This study presents a small-sample-oriented, leakage-aware support vector regression (SVR) framework with a radial basis function (RBF) kernel for Fs prediction. A database of 80 published circular-failure slope cases was compiled, and six predictors were adopted: soil unit weight, slope height, pore pressure ratio, cohesion, internal friction angle, and slope angle. To improve reliability under limited-data conditions, preprocessing, hyperparameter tuning, and performance evaluation were all embedded within a repeated nested cross-validation framework. The proposed SVR model was benchmarked against the back-propagation neural network (BPNN) and radial basis function neural network (RBFNN) models under identical validation partitions and evaluation settings. The results indicated that SVR achieved the best predictive performance among the three candidate models. For case-level illustration, a single representative hold-out split was reported in addition to the repeated nested cross-validation results, on which the SVR model attained an R² of 86.56%, an RMSE of 0.07497, an MAE of 0.0666, and an MRE of 5.29%. In this test subset, all SVR predictions exhibited relative errors below 10%, indicating more stable predictive behaviour than the benchmark models. The main contribution of this study is thus a validated SVR framework for small-sample conditions. Full article

Water-soluble viscosity-modifying admixtures (VMAs) were initially introduced into cementitious materials to enhance cohesion, stability and resistance to bleeding and segregation. With the development of self-compacting concrete, underwater concrete, grouting materials and 3D-printed cementitious materials, VMAs have become increasingly important for regulating rheological behavior, workability retention, shape retention and construction processability. Recent studies further indicate that VMAs can affect not only fresh-state properties, but also hydration kinetics, early-age microstructure evolution, mechanical performance, transport behavior and long-term durability. This review systematically summarizes the types, action mechanisms, and performance effects of water-soluble VMAs in cementitious materials. Particular emphasis is placed on the relationships among the molecular structure, liquid phase viscosity enhancement, particle adsorption and bridging, polymer-chain entanglement, ion-responsiveness, admixture compatibility, and microstructure evolution. The review shows that the effects of VMAs are not governed solely by admixture type or dosage, but depend strongly on molecular mass, functional groups, substituent composition, charge characteristics, binder chemistry, and the pore solution environment. Finally, current research gaps and future directions are discussed, including quantitative structure–mechanism–performance relationships, applicability in low-carbon binders, service-life prediction, and application-oriented VMA design. Full article

Bedding fractures strongly influence pore structure and anisotropic flow capacity in laminated shale oil reservoirs, but conventional porosity–permeability relationships cannot adequately explain permeability differences caused by bedding orientation and fracture connectivity. This problem represents an important gap in shale oil reservoir evaluation because cores with similar porosity may exhibit markedly different permeability when bedding-fracture connectivity and flow direction differ. The main question addressed in this study is how bedding-fracture structures in paired horizontal and vertical LGS shale oil cores selected from the same depth intervals influence porosity, permeability, and permeability anisotropy. To answer this question, this study establishes a quantitative framework linking X-ray computed tomography-derived bedding-fracture structure, three-dimensional fractal dimension, and stress-sensitive permeability anisotropy in LGS shale oil cores. Paired horizontal and vertical cores from the same depth intervals were tested under confining pressures of 10–50 MPa. X-ray computed tomography reconstruction was used to extract bedding-fracture volume fraction $V_f,$ fracture number $N_b$, fracture density ${\rho }_b$, connectivity index $C_b$, and three-dimensional box-counting fractal dimension $D_3$. The H-series cores exhibit much higher bedding-parallel permeability than the V-series cores, although their porosity ranges partly overlap. At 10 MPa, the average permeability of the H-series is 0.24402 mD, approximately 21.7 times that of the V-series 0.01127 mD. As confining pressure increases from 10 to 50 MPa, the average permeability decreases by approximately 97.1% for the H-series and 96.5% for the V-series, indicating strong stress sensitivity of bedding-fracture-controlled flow channels. The $D_3$ values range from 2.16 to 2.63 for the H-series and from 2.12 to 2.56 for the V-series. Higher $D_3$, $V_f$, and $C_b$ enhance permeability when bedding fractures are aligned with the flow direction, whereas complex but discontinuous bedding structures may still result in low bedding-normal permeability. A fractal-corrected porosity–permeability model incorporating $\phi$, $V_f$, $C_b$, and $D_3$ is proposed to improve permeability interpretation beyond porosity alone. This study demonstrates that permeability anisotropy in LGS shale oil cores is controlled by the combined effects of pore–fracture volume, directional connectivity, fractal complexity, and stress-induced fracture closure. Full article

Permeability acts as a core parameter governing the efficient and cost-effective development of deep coalbed methane (CBM) reservoirs. The evolution of permeability in deep CBM formations is predominantly driven by the coupled deformation of pore and fracture systems under in-situ stress, yet the intrinsic mechanisms behind this process have not been fully elucidated. In this work, permeability tests were carried out on cataclastic coal specimens in three orientations under both loading and unloading conditions with confining pressures. Experimental results reveal that coal permeability decreases exponentially with increasing effective stress (R² is about 0.99; reduction is about 86%), exhibiting strong anisotropy and displays significant hysteresis during unloading. To interpret these phenomena, we establish a dual-pore fractal series model that uniquely integrates serial flow coupling between matrix pores and fractures and quantifies stress-driven changes in fractal dimension, tortuosity, and maximum pore size. The model successfully reproduces experimental results (mean relative error ≤ 4.2%) and provides mechanistic insights into stress-induced permeability evolution. Stress increases fractal dimension and tortuosity while reducing maximum pore size, rendering pore structures more complex and less conductive. Incomplete recovery of fractal parameters during unloading explains the observed hysteresis. This mechanistic framework, combining the experiment and theory, offers quantitative support for optimizing CBM extraction strategies. Full article

Jet grouting (JG) is widely used for soil improvement, excavation support, and groundwater cut-off works, often under groundwater conditions and in proximity to sensitive receptors. The same high-energy erosion–mixing mechanisms that enable JG performance can also generate environmental and operational risks, including ground deformation, pore-water pressure transients, unintended hydraulic connectivity, accidental releases of grout or fluids, contaminant mobilisation, and groundwater-quality disturbance. This review synthesises field- and practice-based findings into a monitoring-oriented decision-support structure that links Source–Pathway–Receptor mechanisms with measurable early-warning indicators and predefined response actions. The study does not propose a new numerical or constitutive model; instead, it operationalises dispersed case-based evidence into a structured basis for project-specific monitoring and Trigger–Action Plan development. The analysis is organised into six recurring pathway classes: deformation response, pore-pressure and hydrogeological response, hydraulic incidents, contaminated-ground controls, barrier performance, and spoil/returns management. Across cases, escalation is rarely governed by a single absolute threshold. Instead, it is more reliably identified when an abnormal response increases with time, persists after jetting pauses, spreads beyond the expected influence zone, or is confirmed by more than one source of evidence, such as instrumentation, process behaviour, and field observations. Based on these patterns, the paper develops a generic, project-calibrated Trigger–Action Plan (TAP) structure to support risk-informed construction control, reduce environmental disturbance, protect groundwater and other sensitive receptors, and improve the environmental consistency of jet grouting practice. Full article

Recycled aggregates (RAs) from construction and demolition waste (CDW) provide substantial circular-economy benefits, yet their elevated porosity, adhered mortar, and heterogeneity typically impair the mechanical performance and durability of recycled aggregate concrete (RAC). This PRISMA 2020-compliant systematic review synthesises 2180 records (2015–2026) to evaluate advanced strategies for enhancing RA quality prior to structural use. This paper critically compares removal-based treatments (mechanical, thermal, acid cleaning) with strengthening and densification approaches, including accelerated carbonation, pozzolanic and nano-silica coatings, polymer impregnation, microbial-induced calcium carbonate precipitation (MICP), and modified mixing methods such as triple-stage mixing (TSMA). Evidence shows that while all RA types (including recycled fine aggregate (RFA), recycled coarse aggregate (RCA), and their combination (RFCA)) can slightly reduce compressive strength and 30% replacement serves as a critical threshold, beyond this, strength loss accelerates, particularly in RCA and RFCA mixes. However, accelerated carbonation and TSMA consistently refine the interfacial transition zone, reduce water absorption by 17–30%, and recover 85–94% of natural aggregate concrete strength. Bio-deposition reduces water absorption by 13–21%, while acid/silica fume treatments improve late-age strength but carry environmental trade-offs. This review formulates a practice-oriented implementation framework for structural-grade RAC. Sustainability analyses indicate that carbonated RA can achieve net-positive CO₂ abatement when under low-carbon energy supply. A mechanistic schematic is presented to synthesise treatment-to-pore-structure/durability pathways across the four principal treatment routes, and a quantitative synthesis plot compares water absorption reductions across all treatment types using 13 data points drawn from included studies. A structured treatment comparison evaluates the energy intensity, industrial scalability, CO₂ footprint, and technology readiness level for each strategy. The remaining challenges include a lack of hybrid treatment studies, limited real-scale durability data, and insufficient mechanistic models linking treatment to pore structure evolution. This review recommends harmonised durability-based criteria and updates to standards (e.g., BS 8500, EN 12620) to support the scalable deployment of treated RA. Full article

Sodium-ion batteries (SIBs) are emerging as attractive electrochemical energy-storage systems owing to the natural abundance and low cost of sodium resources. However, their structural integrity and electrochemical stability under mechanical abuse remain insufficiently understood, particularly from the perspective of coupled morphological and transport responses in porous electrode assemblies. In this work, the material deformation behavior and electrochemical evolution of SIBs under compressional loading are systematically investigated, with particular attention to the roles of state of charge (SOC), electrode microstructure, and separator integrity. Electrochemical impedance analysis reveals that the ohmic response is mainly dominated by the extent of compressional deformation, whereas interfacial and diffusion-related resistances are jointly regulated by deformation and SOC. In particular, elevated SOC significantly intensifies the increase in diffusion impedance during compression, indicating a strong coupling between sodium-storage state and mass-transport deterioration. Moreover, cells at higher SOCs exhibit accelerated open-circuit voltage decay during extrusion, suggesting enhanced internal stress accumulation and aggravated instability of the electrode/electrolyte interface. Post-mortem morphological characterization demonstrates substantial particle fracture, pore collapse, and crack propagation in both cathode and anode materials, accompanied by severe shrinkage and partial destruction of the separator microporous network. These results establish a direct correlation between compressional deformation, microstructural damage, and electrochemical degradation in SIBs, and provide useful insights for the design of mechanically resilient electrode architectures, separator materials, and safety-oriented diagnostic strategies for next-generation sodium-ion energy-storage devices. Full article

In recent years, the application of fly ash concrete (FAC) has witnessed a remarkable expansion worldwide. Compared with ordinary Portland cement (OPC), the incorporation of fly ash (FA) reduces the consumption of cement, realizes solid waste resource utilization, and concurrently cuts down carbon emissions from cement production, thus yielding notable environmental benefits. With the gradual popularization of concrete carbon sequestration technology, the research focus of academic circles on concrete carbonation behavior has shifted from the traditional orientation of “optimizing carbonation resistance” to the new direction of “enhancing carbon sequestration efficiency”. Nevertheless, current research on the mechanical properties, durability, and other behaviors of FAC after carbonation remains scarce, lacking systematic and in-depth exploration, and the mechanism underlying the impacts of carbonation on material properties still requires further systematic collation and generalization. Consequently, research on the carbonation behavior of FAC holds profound academic significance and promising application value. This paper reviews the microscopic mechanisms and influencing factors of FAC carbonation; summarizes and analyzes the effects of FAC carbonation on its various properties and microscopic pore structure; introduces the innovative breakthroughs in FAC technology in recent years; and finally, prospects future research directions. It is anticipated to provide a valuable reference for subsequent relevant studies. Full article