Optimization of Process Conditions for Ultralightweight Steel with More Than 13 wt% of Al and 5 wt% of Cr

An ultralightweight Fe–30Mn–13.2Al–1.6C–5Cr steel, which contains more than 13 wt% of Al and thereby reduces the density by 20%, is developed. The ultralightweight steel, which is very brittle due to high Al content, is fabricated by optimizing hot rolling and heat treatment conditions. Hot rolling is conducted after soaking at the temperature range of 1100–1200 °C for 2 h. The ultralightweight steel is hot-rolled successfully after soaking at 1100 °C, whereas specimens soaked at 1150 and 1200 °C are intergranularly cracked after hot rolling, resulting from coarse grain and a large fraction and size of ferrite, which is transformed to ordered DO₃ phase during cooling, at the grain boundaries. In homogenization heat treatment, water quenching and air cooling are performed, respectively, after holding at 1050 °C for 2 h. The air-cooled steel has inferior tensile property due to the formation of brittle ordered DO₃ phase at grain boundaries. Meanwhile, the water-quenched steel shows an excellent tensile property, which is attributed to a uniform microstructure comprising austenite, fine κ-carbide in austenite, and a very small fraction of the ordered DO₃ phase.     

Rheological characterisation of yolk-based gels and Staphylococcus growth

Model yolk-based (10% v/v) gels with different concentrations of κ-carrageenan (0–2% w/w) were characterised employing rheological measurements, textural analysis and scanning electron microscopy. Additionally, the effect of the microstructure of the model gels on the growth rate of Staphylococcus was also evaluated. In all cases, the nature of the gel was dominated by the elastic component, specifically, 1.5, 1.75 and 2% κ-carrageenan samples can be described as ‘true gels’ (tan δ < 0.1). Maximum strength of the interactions between rheological units (A) was observed with 1.75% κ-carrageenan (4.74 ± 0.38 kPa), which indicates that the strength of interactions was determined not only by κ-carrageenan concentration, but also by the amount of yolk. Finally, an inverse linear correlation was found between the maximum specific growth rate of Staphylococcus and rheological data (R² > 0.99).     

抗性糊精对κ-卡拉胶凝胶特性的影响

通过在κ-卡拉胶中添加不同浓度的抗性糊精,研究抗性糊精对κ-卡拉胶凝胶的冻融稳定性、热稳定性、压缩模量及微观结构的影响.结果表明,加入抗性糊精的κ-卡拉胶凝胶在冻融循环中水分析出明显减少,且与抗性糊精的添加量呈正相关.热稳定性结果显示,在抗性糊精添加量4％时,κ-卡拉胶凝胶的分解温度和反应活化能时达到最大(257.86...     

Desalted duck egg white nanogels combined with κ-carrageenan as stabilisers for food-grade Pickering emulsion

There was an extensive interest in food-grade Pickering emulsions formulated by natural stabilisers owing to the gradual growing demand for pursuing green-label products. Based on this, the desalted duck egg white nanogels (DEWN) combined with κ-carrageenan (CAR) (CAR/DEWN) were used as stabilisers to prepare environment-friendly Pickering emulsions. The DEWN and CAR/DEWN as well as the particles-stabilised emulsions were all characterised. Compared with the DEWN- and CAR-stabilised emulsions, Pickering emulsions based on CAR/DEWN were investigated to illustrate the long-term stability according to the results of visual appearance, static multiple light scattering and centrifugation experiments. In addition, CAR/DEWN could prepare stable high internal phase emulsions, which may give a new perspective for nutraceutical or drug encapsulation and delivery. Adding CAR to the DEWN not only increased the apparent viscosity of the emulsions to 122.2% but also enhanced the thixotropic recovery rate to 87.7%. In general, CAR/DEWN as stabilisers significantly promoted the Pickering emulsions' properties, and provided a possibility for the application of Pickering emulsion in foods.     

Preparation of Chloride Salt of Octa (Aminopropylsilsesquioxane) Filled Low-κ Epoxy Composites with Improved Thermal Stability and Low Water Absorption

ABSTRACT

Herein, a kind of low-κ epoxy composites with excellent comprehensive properties were prepared by introducing chloride salt of octa (aminopropylsilsesquioxane). The dielectric constant (10⁶ Hz) of the composite was decreased by 0.94 when the fillers loading was only 3 wt%. The thermal stability and shore hardness were both improved, and the water adsorption was reduced. The improved properties of the composites were mainly attributed to the intrinsic cage-like structure of the filler and its good dispersion in the matrix. Moreover, the strong interface interaction between the filler and matrix also played an important role.