Bimodal-grained microstructure and fully recrystallized microstructure were fabricated in a Mg-11Gd-3Y-0.5Nd-Zr alloy, respectively, by varying the extrusion speed, and their influence on superplastic behavior was studied. The results show that the bimodal-grained microstructure significantly enhances the super-plasticity. The maximum elongation of 754% was achieved in the bimodal-grained microstructure under 425 degrees C and 5 & times; 10-4 s-1, with a maximum strain rate sensitivity index ( m ) of 0.69 and a deformation activation energy ( Q ) of 211 kJ/mol. In contrast, the fully recrystallized microstructure attained a maximum elongation of 442% at 425 degrees C and 1 & times; 10-3 s-1, with a maximum m value of 0.59 and a Q value of 435 kJ/mol. It suggests that grain boundary sliding (GBS) controlled by lattice diffusion is the main superplastic deformation mechanism for both specimen groups, and microstructure evolution indicates that slip is also an important coordination mechanism. Within the bimodal-grained microstructure, the elongated un-dynamically recrystallized grains underwent dynamic recrystallization (DRX) during the initial stage. This process led to a layered heterogeneous microstructure with alternating coarse and ultrafine grains, which promoted GBS and facilitated the dissolution of pre-existing dynamic precipitates. Consequently, cavity formation was effectively delayed and exhibited notable superplasticity. (c) 2026 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
Wet chord grids intensify gas–liquid contact by converting a dispersed spray into a wire-supported interface, but the coupled roles of wettability, liquid morphology, and thermodynamic irreversibility remain unclear. Pristine, hydrophilic, and hydrophobic grids were compared under matched airflow and spray conditions using high-speed imaging, infrared thermography, inlet–outlet air-state measurements, and exergy analysis. Because repeated runs were unavailable, measurement uncertainty was evaluated conservatively from Type-B input bounds and propagated with a coverage factor k = 2. The hydrophobic grid maintained a denser population of discrete droplets and a more spatially uniform low-temperature region. Its nominal maximum air-temperature and humidity-ratio reductions were 4.2 °C and 3.7 g·kg−1, compared with 2.9 °C and 3.0 g·kg−1 for the pristine grid and 2.9 °C and 2.6 g·kg−1 for the hydrophilic grid. Expanded uncertainty was 0.82 °C for the temperature reduction and 1.85–1.92 g·kg−1 for the humidity-ratio reduction; thus, the temperature separation is marginal, whereas the humidity-ratio ranges overlap. Nominal exergy efficiency increased from about 90.5% for the single spray to about 92% with the grid, but the propagated bounds do not resolve this small difference. The combined images and nominal responses support a wettability-dependent balance among retention, drainage, and interface renewal, while quantifying the repeatability and calibration evidence required for a transferable design claim.
In the realm of mathematics, the hereditary property is a crucial characteristic. Heredity in a mathematical structure clarifies its internal architecture and drives related research forward. Suppose that D is a nontrivial design with automorphism group G. We have accomplished the classification of all hereditary (G, 3)-flag-transitive designs in this paper, for G is an almost simple group that coincides with its socle.
A bi-normalized input energy spectrum for energy-based seismic design of structures subjected to offshore ground motions (GMs) is presented. The bi-normalized input energy spectrum, Eeq, is obtained by dividing the vibration period of single-degree-of freedom (SDOF) systems by the predominant period and by dividing the input energy equivalent velocity by the spectral pseudo-velocity. A total of 200 offshore GMs obtained from 273 earthquakes and 369 onshore GMs obtained from 263 earthquakes that have occurred in the Japan Sagami Bay Region with magnitude greater than five were employed to assess Eeq. The computer program IDARC2D was used to determine the nonlinear time-history analysis of inelastic SDOF systems for computing the Eeq spectra. The Eeq variation with offshore ground-motion characteristics, the normalized period, displacement ductility ratio, postyield stiffness ratio and hysteretic law is investigated. The differences in Eeq of offshore and onshore GMs are also highlighted. The Eeq was found to be not sensitive in seafloor stations, significant duration, magnitude and epicentral distance. In comparison to onshore GMs, offshore GMs can increase mean Eeq of structural systems, with the magnitude of this increase potentially reaching approximately 20%. Analytical estimates of Eeq were finally introduced to accommodate the extension of the Energy-Based Seismic Design via bi-normalized input energy to structures subjected to offshore GMs.
Coal seam water injection is a key technology for pre-wetting and dust suppression prior to mining, with its effectiveness largely dependent on the wetting capability of water on coal. As a novel wetting medium, micro-nano bubble water (MNBW) has drawn increasing attention due to the close relationship between its wettability and preparation parameters, though the underlying mechanisms remain unclear. To address this, physicochemical characterization, contact experiments, and molecular simulations were carried out. Results showed that increasing the gas flow rate during MNBW preparation enhanced its properties: scattered light intensity, interfacial potential, and dissolved oxygen content increased, while surface tension and bubble size decreased, indicating improved system stability. The contact angle on the coal surface decreased accordingly and was positively correlated with dissolved oxygen and interfacial potential but negatively correlated with bubble size. This suggests that higher gas flow rates promote wetting by increasing bubble concentration, lowering surface tension, and enhancing stability. After MNBW treatment, the oxygen content on the coal surface increased by 10.1%, accompanied by significant enrichment of oxygen-containing functional groups such as –OH and –COOH. Molecular simulations revealed stronger adsorption of water molecules in hydroxyl-rich regions, with a 45% increase in the relative concentration of water molecules at the coal–water interface, enhanced interaction energy, and a markedly reduced contact angle. These findings provide a theoretical basis for optimizing MNBW-assisted coal seam water injection technology.
