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Some embankment dam distress or failures are associated with suffusion under seepage forces, and the onset of suffusion occurring within an embankment core or the foundation of a dam is governed by the hydro-mechanical conditions within the soil and initiated where seepage force exceeds a critical threshold. The main objective of this study is to discuss the critical hydro-mechanical conditions of suffusion initiation. Theoretical formulas and models previously proposed for determining the critical hydraulic gradient of suffusion initiation are summarized and compared first, as well as their limitations, and then a new equation based on the seepage force concept is proposed. A case study is conducted to verify the new equations, and comparison with the experimental result indicates that the new proposed equation may be more reasonable than others. [ABSTRACT FROM AUTHOR]

The development of high-performance ultraelastic metals with superb strength, a large elastic strain limit and temperature-insensitive elastic modulus (Elinvar effect) are important for various industrial applications, from actuators and medical devices to high-precision instruments1,2. The elastic strain limit of bulk crystalline metals is usually less than 1 per cent, owing to dislocation easy gliding. Shape memory alloys3—including gum metals4,5 and strain glass alloys6,7—may attain an elastic strain limit up to several per cent, although this is the result of pseudo-elasticity and is accompanied by large energy dissipation3. Recently, chemically complex alloys, such as ‘high-entropy’ alloys8, have attracted tremendous research interest owing to their promising properties9–15. In this work we report on a chemically complex alloy with a large atomic size misfit usually unaffordable in conventional alloys. The alloy exhibits a high elastic strain limit (approximately 2 per cent) and a very low internal friction (less than 2 × 10−4) at room temperature. More interestingly, this alloy exhibits an extraordinary Elinvar effect, maintaining near-constant elastic modulus between room temperature and 627 degrees Celsius (900 kelvin), which is, to our knowledge, unmatched by the existing alloys hitherto reported.A chemically complex alloy that exhibits a high elastic strain limit and low internal friction is described; it also has an Elinvar effect (invariant elastic modulus) over a large temperature range, up to 627 °C. [ABSTRACT FROM AUTHOR]

The compositional design of metallic glasses (MGs) is a long-standing issue in materials science and engineering. However, traditional experimental approaches based on empirical rules are time consuming with a low efficiency. In this work, we successfully developed a hybrid machine learning (ML) model to address this fundamental issue based on a database containing ~5000 different compositions of metallic glasses (either bulk or ribbon) reported since 1960s. Unlike the prior works relying on empirical parameters for featurization of data, we designed modeling guided data descriptors in line with the recent theoretical models on amorphization in chemically complex alloys for the development of the hybrid classification-regression ML algorithms. Our hybrid ML modeling was validated both numerically and experimentally. Most importantly, it enabled the discovery of MGs (either bulk or ribbon) through the ML-aided deep search of a multitude of quaternary to scenery alloy compositions. The computational framework herein established is expected to accelerate the design of MG compositions and expand their applications by probing the complex and multi-dimensional compositional space that has never been explored before. [ABSTRACT FROM AUTHOR]

Trace amounts of selenium (Se) are essential for several organisms, and deficiencies therein have adverse effects on growth, development, and reproduction; this is particularly significant in animals raised for milk and livestock production. To study the effect of Se on Guanzhong dairy goats, their diets were supplemented with different sources (inorganic or organic) and Se concentrations (0.2 or 0.4 mg Se/kg). A non-Se-fortified basal diet served as a negative control, and a sixth treatment group received both inorganic and organic Se sources (0.2 mg Se/kg diet each). Dietary Se supplementation increased milk production, with organic Se being more effective than inorganic Se. Selenium supplementation also increased Se concentration and glutathione peroxidase activity in whole blood, with organic Se more effective than inorganic Se at the same Se concentration. With increasing Se in diets, the Se content in milk increased markedly, reaching a plateau value at day 30 in all groups, and organic Se (0.4 mg/kg diet) had the best effect. In addition, dietary Se sources and concentrations markedly affected Se concentrations in different tissues and organs. Thus, organic Se supplementation of a basal diet at 0.4 mg/kg is practically applicable for Se-enriched milk and meat production in Guanzhong dairy goats. [ABSTRACT FROM AUTHOR]

By applying fumed SiO2 and the deposition–precipitation method based on organic medium, the composite VPO/fumed SiO2 catalysts were first prepared and tried for partial oxidation of n-butane to maleic anhydride. In the temperature range of 653–693 K the fumed SiO2-based catalysts not only showed good activity but also maintained sufficiently high MA selectivity in comparison to some conventional supported VPO catalysts. As an example, the catalyst with 30% VPO content showed butane conversion of 60% and MA selectivity of 58 mol% at 673 K. The turnover rates of low loading samples are found to be higher than that of high loading sample as well as unsupported catalyst. Besides the unique interaction which may exist between VPO component and the fumed SiO2 material, co-existence of dominant (VO)2P2O7 and minor VOPO4 in these non-equilibrated catalysts may be favorable for MA formation. Moreover, introducing the additive of polyethylene glycol (PEG) in the preparation medium can obviously enhance the dispersion of VPO component and hence lead to a more selective catalyst. [ABSTRACT FROM AUTHOR]

The partial sterility of hybrids between the indica and japonica rice subspecies of Asian cultivated rice is a serious constraint for utilizing inter-subspecific heterosis in hybrid rice breeding. In this study, we have investigated the relationship between molecular-marker polymorphism and indica-japonica hybrid fertility using a diallel set involving 20 rice accessions including 9 indica and 11 japonica varieties. Spikelet fertility of the resulting 190 F1s and their parents was examined in a replicated field trial. Intra-subspecific hybrids showed much higher spikelet fertility than inter-subspecific hybrids except in crosses involving wide-compatibility varieties. The parents were surveyed for DNA polymorphism using 96 RFLP and ten SSR markers, which revealed extensive genetic differentiation between indica and japonica varieties. A large number of markers detected highly significant effects on hybrid fertility. The chromosomal locations for many of the positive markers coincided well with previously identified loci for hybrid sterility. The correlation between hybrid fertility and parental distance was low in both intra- and inter-subspecific crosses. The results suggest that the genetic basis of indica-japonica hybrid sterility is complex. It is the qualitative, rather than the quantitative, difference between the parents that determines the fertility of hybrids. [ABSTRACT FROM AUTHOR]