Concrete has low porosity and compact microstructure, and thus can be vulnerable to high temperature, and the increasing application of various types of supplementary cementitious materials (SCMs) in concrete makes its high-temperature resistant behavior more complex. In this study, we investigate the effects of four formulations with typical SCMs combinations of fly ash (FA), ultra-fine fly ash (UFFA) and metakaolin (MK), and study the effects of SCMs combinations on the thermal performance, microstructure, and the crystalline and amorphous phases evolution of concrete subjected to high temperatures. The experimental results showed that at 400 °C, with the addition of 20% FA (wt %), the thermal conductivity of the sample slightly increased to 1.5 W/(m·K). Replacing FA with UFFA can further increase the thermal conductivity to 1.7 W/(m·K). Thermal conductivity of concrete slightly increased at 400 °C and significantly reduced at 800 °C. Further, combined usage of SCMs delayed and reduced micro-cracks of concrete subjected to high temperatures. This study demonstrates the potential of combining the usage of SCMs to promote the high-temperature performance of concrete and explains the micro-mechanism of concrete containing SCMs at high temperatures.

A titanium-chromium-oxide catalyst was prepared by a facile calcination of titanium-modified MIL-101(Cr). The resulting material, possessing a surface area of 60 m² g⁻¹ and a titania content of 50.0 wt%, can be directly used as the catalyst for oxidative desulfurization (ODS) reaction of dibenzothiophene (DBT). This novel ODS catalyst can remove 900 ppm sulfur-containing compounds in a reaction time of 30 min at 60 °C. The experimental results showed that the specific activity increased with the titanium content. The specific activity of the catalyst with 50%Ti reached 129 μmol/m², which was much higher than that of reported Ti-based catalysts.

Wire Arc Additive Manufacturing (WAAM) for the fabrication of lightweight Al alloy represents a burgeoning area of research. Despite this, the presence of porosity defects, coarse surface grain sizes, and the clustering of precipitated phases in WAAM-produced Al alloy samples have been identified as detrimental to their mechanical properties, rendering them inadequate for contemporary service requirements. In this investigation, an innovative approach termed Ultrasonic-Rotating Extrusion-Wire Arc Additive Manufacturing (U-RE-WAAM) was proposed, which integrates the synergistic effects of ultrasonic and mechanical force fields into the WAAM process. Comparative analysis were conducted on defects, microstructure and mechanical properties between WAAM and U-RE-WAAM samples to investigate the impact of U-RE-WAAM on aluminum alloy samples. The results show that the mechanical force field causes a large amount of plastic deformation, which refines the grain size and restructures the precipitation phase from clustered aggregates to a fine dispersion. Furthermore, the U-RE-WAAM process achieves a reduction in porosity and an enhancement in grain size and precipitated phase distribution by the coupling of mechanical force field and ultrasonic energy field. Consequently, the mechanical properties of U-RE-WAAM samples are markedly superior, with a 32.8% increase in hardness and significant improvements in yield strength 81%, ultimate tensile strength 41%, and elongation 38.9%.