CoCrFeNiMox (x = 0, 0.4, 0.8, and 1.2) high-entropy alloy (HEA) coatings were deposited on a CrZrCu alloy substrate by laser cladding, and the effects of Mo content on phase evolution, interfacial characteristics, and tribological behavior were investigated. The results showed that increasing the Mo content transformed the coatings from a single face centered cubic (FCC) solid solution into an FCC + σ dual phase structure. At x = 0.8, the Mo- and Cr-rich precipitates evolved from discrete island-like features into a lamellar σ phase structure. High-resolution TEM (HRTEM) and geometric phase analysis (GPA) analyses indicated that the σ phase and FCC matrix in the Mo0.8 coating exhibited pronounced local semi-coherent interfacial features and localized strain, thereby enhancing near-surface resistance to deformation during sliding. Although the microhardness increased monotonically with Mo content, the Mo0.8 coating showed the best wear resistance, with an average coefficient of friction (COF) of 0.53 and a wear rate 80.95% lower than that of the Mo0 coating. The X-ray photoelectron spectroscopy (XPS) results show that the oxidation products of Mo and Cr form an oxide-rich surface reaction layer on the worn surface and the near-surface region of the Mo0.8 coating. Excessive Mo addition at x = 1.2 reduced wear resistance because of a higher fraction of brittle phases, aggravated cladding defects, and intensified three-body wear. The superior wear resistance of the Mo0.8 coating is attributed to the synergistic effects of its lamellar σ phase structure, local interfacial characteristics, and surface reaction layer.
The variations of Southern Hemisphere Westerlies (SHW) influence ocean circulation and the global carbon cycle, and thus, play a crucial role in global climate. Earlier studies showed the SHW undergo poleward-intensifying under anthropogenic climate change. However, it is controversial whether such a trend is driven by purely atmospheric processes or a coupled ocean-atmosphere response. Here, we investigate the dynamical mechanisms of SHW changes by providing three different scenarios under abrupt rising, long-term stabilizing, and abrupt decreasing CO_2 forcing based on three numerical experiments. The results indicate that under abrupt rising CO_2 forcing, the SHW strengthens and shifts poleward. As CO_2 stabilizes, the SHW’s intensity weakens but remains stronger than the cold climate. Its position remains at a higher latitude. Entering a cooling climate, forced by abruptly decreasing CO_2 , the intensity of SHW rapidly reduces, displaying a tendency for equatorward reversal. By comparing the behavior of SHW under the same atmospheric CO_2 forcing, the contribution of ocean dynamics to SHW can be identified. Our results reveal that the location of SHW is aligned with the position of the oceanic meridional temperature gradient (MTG), while the intensity of SHW is coupled to the ocean-perturbed meridional heat imbalance. Both depend on the fast and slow response times of the subtropical and subpolar oceans to CO_2 forcing, modulated by the downwelling and upwelling nature of these ocean regions. Our results reveal that the response of SHW to CO_2 forcing depends on the background state of the Southern Ocean. This provides insights into the evolution of SHW.
The development of host-derived probiotics presents a forward-looking nutritional component strategy for sustainable aquaculture. However, research on host-associated probiotics for the globally farmed American bullfrog (Aquarana catesbeiana) is limited. The research put Bacillus velezensis (BLS) isolated from bullfrog guts determine its probiotic potential. Bullfrogs were divided into two groups: one fed a control diet and the other fed a diet enriched with 1 × 10⁸ CFU/g BLS for 7 weeks. BLS supplementation significantly enhanced growth performance and markedly decreased mortality after challenge with Streptococcus agalactiae. Relative to controls, the BLS cohort demonstrated heightened activity of essential antioxidant enzymes (CAT, GSH-Px, and SOD) and lower malondialdehyde levels in liver and intestinal tissues. Moreover, BLS supplementation enhanced intestinal structure, demonstrated by markedly increased villus height and goblet cell count, alongside enhanced hepatocyte arrangement and tissue integrity. Gut microbiome analysis revealed that BLS elevated the proportion of Firmicutes while decreasing the proportion of harmful genera such as Elizabethkingia. These findings suggest that the probiotic effects are mediated through the modulation of gut barrier function and microbial community. In conclusion, dietary supplementation with B. velezensis BLS enhanced growth, pathogen resistance, antioxidant capacity, and bowel health in bullfrogs through enhanced intestinal morphology and microbiome regulation. Consequently, supplementation holds significant promise as a probiotic in bullfrog farming.
In this work, the novel FeNi-LDH/NF and (Fe-Ni)Ox/NF were prepared using facile hydrothermal and calcination methods. The electrocatalyst FeNi-LDH/NF ((Fe-Ni)Ox/NF) exhibits excellent HER catalytic activity, and produced an overpotential of 147 (210) mV at 10 mA cm−2 with a small Tafel value of 97 (100) mV dec−1 in 1.0 M KOH electrolyte. Due to the high-density active centers exposed on the surface of FeNi-based hydroxides, their electrical conductivity, and the synergistic effect between the metals, the catalytic activity of FeNi-based hydroxides is superior to that of FeNi-based oxides. The overall experimental findings showcase a feasible approach for exploring the potential of the nonprecious metal-based FeNi-LDH/NF ((Fe-Ni)Ox/NF) nanoelectrocatalyst towards alkaline HER.
This study investigates the use of waste coral sand powder (CSP) combined with metakaolin (MK) to develop an eco-friendly ternary binder, coral sand calcined clay cement (CSC3), for marine infrastructure. The binder replaced 45
