During the continuous casting of high‐Al steel, the dynamic reduction of silica‐based mould fluxes by the aluminium in the steel leads to changes in their composition and physical properties. The alumina‐based mould flux has been suggested as an alternative to alleviate this reduction problem. However, until now, the smooth running of high‐Al steel continuous casting has been impeded by the lack of systematic investigation of properties of this slag. In this paper, the effects of typical components on the properties of alumina‐based mould fluxes are discussed. The experimental results show that: (a) an increase in F− can reduce the viscosity while increasing the melting and break temperatures; (b) with increasing Li2O, the viscosity, melting temperature, and break temperature first decrease and then increase; (c) with the addition of BaO, the viscosity, melting temperature, and break temperature remain at a low level, while a further increase in BaO causes a decrease in viscosity, an increase in melting temperature, and the stabilization of the break temperature; (d) BaO is favorable to stabilize the properties of mould fluxes for the dissolution of additional Al2O3; (e) the crystalline phases of the mould fluxes mainly contain 12CaO · 7Al2O3 and 11CaO · 7Al2O3 · CaF2, and 12CaO · 7Al2O3 has great potential as a substitute for cuspidine.

No abstract

Concrete-filled square steel tube column (CFSSTC) joints are the most important parts of concrete-filled steel tube frame structures. It is of great significance to study the damage of CFSSTC joints under the seismic loads. In this paper, embedded piezoceramic transducers are used to monitor the damage of core concrete of CFSSTC joints under cyclic loading and surface-bonded piezoceramic disks are used to monitor the debonding damage of the steel tube and core concrete of two specimens. The damages of the joints under different loading levels and different loading cycles are evaluated by the received signal of the piezoceramic transducers. The experimental results show that the amplitude of the signal attenuates obviously with the appearance of damage in the joints, and the degree of attenuation increases with the development of the damage. The monitoring results from piezoceramic transducers are basically consistent with the hysteresis loops and skeleton curves of the CFSSTC joints during the cyclic loading. The effectiveness of the piezoceramic transducers are verified by the experimental results in structural health monitoring of the CFSSTC joint under cyclic loading.

This study was aimed at evaluating the effect of two cooking methods on in vitro digestibility of starch and the change in its microstructure. Rice was cooked by microwave and conductive heating (CH), then stored at −18, 4, 25°C, the in vitro digestibility of starch was measured by in vitro simulative digestion method and the micromorphology was obtained by SEM. Rice starch heated by microwave had greater swell and smaller gaps between starch granules when compared with that heated in a conductive way. The concentrations of reducing sugar and glucose of in vitro digestibility of the rice starch cooked by microwave heating (MH) are higher than that by CH (p≤0.01). After storage, the in vitro digestibility of starch lowered, namely, the content of rapidly digestible starch (RDS) decreased, however, the content of slowly digestible starch (SDS) and resistant starch (RS) increased. After 72 h of storage the in vitro digestibility of rice starch cooked by MH was inferior to that by CH. The higher the storage temperature was, the worse the in vitro digestibility of starch was. This applied to both heating methods. The best digestibility effect was achieved when the rice was cooked by MH and stored at −18°C. Meanwhile, the kinetic model of in vitro digestibility of starch demonstrated that the equilibrium percentage and kinetic constant of the reducing sugar and glucose declined as the storage time increased.

The characteristics of the steel solidification in continuous casting, especially the peritectic reaction, have a considerable effect on the surface quality of the cast blanks. This study employed the FactSage software and thermodynamic calculation to determine the effects of various elements on the carbon content at the peritectic point (Cp) at equilibrium conditions for regular carbon and low alloy steels. . Furthermore, the accuracy for the carbon content at the peritectic reaction was indirectly validated by comparing the liquidus, solidus and austenite formation temperatures from the calculated phase diagrams with literature data. Moreover, statistical analysis was performed on the longitudinal crack ratio for slabs produced in a commercial plant to determine the tendency for the peritectic reaction. The results show that when the cooling rate is taken into consideration, the difference between actual carbon content and predicted Cp is negatively correlated with the longitudinal crack rate.