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This paper introduces a methodology to predict the non-linear stiffness–suction and shear strength–suction relationships for unsaturated soils within the lower suction range from the non-linearity of the soil-water characteristic curve (SWCC), using a normalised function formulated with ‘suction times exponential degree of saturation’. The information required in this methodology includes (a) measurements of the shear strength or stiffness properties at saturation condition and one unsaturated condition and (b) the SWCC. Published experimental data on the stiffness and shear strength properties and the SWCC obtained from 25 different soils varying from coarse-grained sands to expansive clays are used to validate the proposed normalised function and to calibrate the exponent value. It is found that the normalised function, using exponent values of 1·0 and 2·0, respectively, for cohesionless and cohesive soils, provides reasonable predictions of the stiffness–suction and shear strength–suction relationships for all the soils used in this study, taking account of various influencing factors including external stress, soil structure, anisotropy, hydraulic hysteresis and testing technique.

Alginate oligosaccharides (AlgO), agarose oligosaccharides (AO), and κ-carrageenan oligosaccharides (KCO) were obtained by specific enzymatic hydrolysis method. The molecular weight distributions of the three oligosaccharides were 1.0–5.0 kDa, 0.4–1.4 kDa, and 1.0–7.0 kDa, respectively. The culture medium was supplemented with the three oligosaccharides and fermented by pig fecal microbiota in vitro, for 24 h. Each oligosaccharide was capable of increasing the concentration of short-chain fatty acids (SCFAs), especially butyric acid, and altering the microbiota composition. Linear discriminant analysis effect size (LEfSe) analysis results showed that the opportunistic pathogenic bacteria Escherichia, Shigella, and Peptoniphilus, were significantly decreased in AlgO supplemented medium. AO could improve the gut microbiota composition by enriching the abundance of Ruminococcaceae, Coprococcus, Roseburia, and Faecalibacterium. Besides, KCO could increase the abundance of SCFA microbial producers and opportunistic pathogenic flora. Therefore, these results indicate that AlgO and AO can be used as gut microbial regulators and can potentially improve animal/human gastrointestinal health and prevent gut disease, whereas the physiological function of KCO needs further evaluation.

Argon oxygen decarburisation-electroslag remelting (AOD-ESR) process has been well used to produce the Fe-Mn-Si-Al twinning induced plasticity steel (TWIP) steels. The characteristics of AlN inclusions formed in TWIP steels after AOD refining, ESR and forging process were investigated by scanning electron microscopy and X-ray energy dispersive spectrometry. An automated program called 'INCAFeature' was used to collect statistics of inclusion characteristics. Great differences on the amount, distribution and morphologies of AlN inclusions were observed in AOD ingots, ESR ingots and forgings. The dominating inclusions in AOD ingots are mainly single Al(O)N and MnS(Se)-Al(O)N aggregate, accounting for 66.7% of the total inclusions. After the ESR process, AlN inclusions in all size range significantly decreased, which were rarely observed in ESR ingots. Thermodynamic calculations show that AlN inclusions can precipitate in the liquid Fe-Mn-Si-Al TWIP steels, which is different from the viewpoint of literatures that the precipitation of AlN inclusions took place at solidifying front or solid phase. Furthermore, the thermodynamic calculation result has been verified by high temperature laser scanning confocal microscope experiments.

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