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In this study, the pore structure and gas permeability of river sand concrete and manufactured sand concrete (mixed with various stone powders) are examined under dry and wet conditions. First, the pore structure of concrete was tested using the mercury-in-pressure (MIP), hydrostatic balance (HB), and nuclear magnetic resonance (NMR) methods. Second, the gas permeability of concrete was measured using the quasi-stationary flow method. Finally, a numerical model was developed based on the relationship between the pore structure and gas permeability. The results indicated that the gas permeability of dry concrete has a quadratic linear relationship with the porosity and volumetric characteristic pore size. The pore structure of partially water-saturated concrete can be corrected using a correction factor and the relaxation rate of the dry material. Finally, a random hierarchical bundle model using the HB–NMR method is proposed. The maximum relative deviation between the predicted and experimental values is 48.28%. [ABSTRACT FROM AUTHOR]

Supplementary cementitious materials (SCMs) are usually employed to replace partial cement and the pore-solution chemistry of blended cements is extremely essential for their cement hydration and durability. In this work, the pore-solutions of cement pastes with various water-to-cement (w/c) ratios and SCMs (fly ash, ground granulated blast-furnace slag and silica fume) are extracted for observing their ions and conductivities. The results illustrate that Na+, K+, OH−, Ca2+ and SO42− are the main and their concentrations are declined by the improving w/c ratios and SCMs dosages and thus decreasing their conductivities. The conductivity evolution shows three typical periods: induction (<5 h), acceleration (5 h-7d) and deceleration (>7d). The pore-solution conductivities of pastes with various w/c ratios are predicted well by the model established (R2 > 0.90) while the SCMs decline the model effectiveness. The OH−, K+ and SO42− provide the conductivities over 90% of the whole with the contributions in decreasing order. [ABSTRACT FROM AUTHOR]

Photoinduced transmembrane ion transport in organisms provides a distinctive perspective for exploiting the ocean enriched with both ions and solar energy. Artificial two-dimensional nanofluidic membranes for photothermal-driven ion transport are facing issues such as interrupted nanofluidic transport and much dissipated heat. Peristome surface of Nepenthes enables stable wetting and rapid directional water transport correlated with orientational sophisticated flow-guiding microstructures, inspiring amelioration of these issues by regulating membrane topographies. A conformal layer-by-layer assembly is adopted to construct superstructured positively charged graphene oxide (PGO)/MXene membranes (SGMMs) that differ from topographies. These membranes enable anion-selective transport enhanced by superstructure configurations via providing more and wider nanofluidic channels than planar PGO/MXene membrane (PGMM). SGMMs with orientational superstructures demonstrate superior wetting performance and directional transport of surface microfluidics compared to PGMM, inducing directional ion transport within nanochannels. Additionally, this superstructure design assists SGMMs to outshine PGMM in photothermal evaporation conspicuously, benefiting from an enlarged surface area and well-regulated surface microfluidic distribution. Eventually, SGMMs enable more remarkable photothermal evaporation-driven ion transport facilitated by directional transport of surface microfluidics and efficient photothermal evaporation. This work emphasizes the significance of membrane topography design for nanofluidic transport toward exploiting the ocean including sunlight, water resources, and ionic energy., Competing Interests: The authors declare no competing financial interest., (© 2025 The Authors. Published by American Chemical Society.)