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The influence of soil variability on the bearing capacity of a foundation has been simulated by various numerical methods. Due to the lack of repeatable tests in spatially variable soil, the effect of the spatial pattern on the failure mechanism of the foundation in a spatially variable soil is physically unclear. This study aims to investigate how the spatial pattern affects the failure mechanism and the bearing capacity of a shallow foundation by the laboratory tests conducted on spatially variable physical soil models. Four physical models were carefully prepared with accurately controlled shear strength according to the random fields of shear strength, which enable the comparison to classical bearing capacity theory. The failure mechanism and the bearing capacity were observed and compared to Terzaghi's theory in homogeneous soils. Results show that the shear failure plane mainly developed in weak soils, which results in an asymmetric failure mechanism. This different failure mechanism leads to a very different bearing capacity of a foundation on variable soils compared to that on homogeneous soils of the same mean shear strength. This study paves a way towards a safe and economical foundation design by considering the effect of spatial variation in soils. [ABSTRACT FROM AUTHOR]

The addition of CrB2and Sr into Al-10Si-0.3 Mg (wt.%)-based alloys not only modify the eutectic Si, but also refine the eutectic grains. CrB2particles were found to nucleate the eutectic grains, despite the AlP particles being partly removed or depleted by the interaction between Sr and AlP. Furthermore, P level was found to be one of the dominant factors that affect the nucleation of eutectic grains. CrB2addition with a low P level results in a refined eutectic grain size, despite less AlP particles being present to nucleate the eutectic grains. Porosity was found to be mainly located at the boundaries of eutectic grains, highlighting the importance of the refinement of eutectic grains to reduce the size and optimise the distribution of porosity. This investigation demonstrates a novel approach to refine eutectic grains and modify eutectic Si simultaneously into Al-10Si-0.3 Mg (wt.%)-based alloys, and thereby suggests possible industrial applications. [ABSTRACT FROM AUTHOR]

The limit analysis and the finite element method are powerful tools for analysing the bearing capacity of foundations. Previous research mainly focused on the foundations in uniform soils. In realistic conditions, soil properties are always varying spatially due to complex physical, chemical, and biological process in earth evolution. This paper investigates the bearing capacity and failure mechanism of footings buried at various depths in clays with spatially variable distribution of undrained shear strength using the lower bound limit analysis, the upper bound limit analysis, and the finite element analysis. Results show that the bearing capacity increases with increasing buried depths in spatially random soils, which is the same as in the uniform soils. The bearing capacity factors calculated using the finite element method, the lower bound limit analysis, and the upper bound limit analysis for a footing in spatially varied soils are all smaller than the corresponding values in uniform soils. The majority of the bearing capacity factors obtained from the finite element method is bounded by those obtained from the lower bound and the upper bound limit analysis. The shear planes show a clearly unsymmetrical manner in spatially varied soils using the three methods, which is different from the symmetrical shear plane in uniform soils. [ABSTRACT FROM PUBLISHER]

To assess the phytoremediation potential of an autochthonous willow (Salix × aureo-pendula CL'J1011') for phenanthrene (PHE)-contaminated soils and PHE-cadmium (PHE-Cd) co-contaminated soils, we conducted field experiments in the lower reaches of the Yangtze River, China. Ethylenediaminetetraacetic acid (EDTA) and ethyl lactate were tested for individual and combined effects on the phytoremediation efficiency. For PHE-contaminated soils, willow plus ethyl lactate resulted in significant removal of PHE from soils after 45 days, and the PHE concentration in the shoots was significantly higher with than without ethyl lactate. For PHE-Cd co-contaminated soils, both willow plus EDTA and willow plus EDTA and ethyl lactate led to a significant decrease in the concentrations of PHE and Cd in the soils after 45 days, whereas willow alone did not. The PHE and Cd concentrations in the willow shoots were significantly enhanced in the presence of EDTA alone and with ethyl lactate, except for the PHE concentration in stems with EDTA alone. Under the same treatment, the presence of Cd had no significant influence on the PHE removal from soils. The results indicate the feasibility of using this willow together with both EDTA and ethyl lactate for the simultaneous removal of PHE and Cd from soils. [ABSTRACT FROM AUTHOR]

The intermetallic phase selection during homogenization in a AA6082 alloy has been investigated. A short homogenization treatment at 580 {\degr}C for 4 h and a subsequent slow cooling with a rate of about 8 {\degr}C/min, rather than a conventional quick quenching into water, results in the formation of the rounded discrete Al15(FeMnCr)3Si2phase, which greatly suppressed the formation of the plate-shaped β-Al5FeSi phase. Most of the Al15(FeMnCr)3Si2particles were observed to be very fine (about 200 nm) and homogeneously distributed in the α-Al matrix. Fine Mg2Si particles were also observed to be located in the vicinity of Al15(FeMnCr)3Si2particles. Additionally, the β series precipitates (most likely β″-Mg2Si), large-scale U2-AlMgSi and B′ (type C) phases were also observed within the α-Al matrix. This investigation demonstrates that the size and distribution of the desired intermetallic phases can be influenced by suitable homogenization treatments. [ABSTRACT FROM AUTHOR]

Energy is of crucial importance in coal flotation. In the present study, a torque sensor was used to measure the energy consumed during flotation experiments carried out using the optimal reagents dosages and concentration. During flotation, with an increase in flotation time, the clean coal ash gradually increased, the flotation rate constantkvalues decreased, and the energy required to recover a unit mass of clean coal became greater. With higher agitation speed, the amount of energy consumed also increased. A model of combustible recovery and flotation energy was established. The flotation behavior of narrow size particle agreed with the unclassified size. The flotation rate order of narrow size was as follows: −250 to +125 μm > −500 to +250 μm > −125 to +75 μm > −75 μm. [ABSTRACT FROM PUBLISHER]

The nucleation and growth of Si has been investigated by TEM in a series of high purity melt spun Al–5Si (wt%)-based alloys with a trace addition of Fe and Sr. In the as-melt-spun condition, some twinned Si particles were found to form directly from the liquid along the grain boundary. The addition of Sr into Al–5Si-based alloys promotes the twinning of Si particles on the grain boundary and the formation of Si precipitates in the α-Al matrix. The majority of plate-shaped and truncated pyramid-shaped Si precipitates were also found to nucleate and grow along {111}α-Al planes from supersaturated solid solution in the α-Al matrix. In contrast, controlled slow cooling decreased the amount of Si precipitates, while the size of the Si precipitates increased. The orientation relationship between these Si precipitates and the α-Al matrix still remained cube to cube. The β-Al5FeSi intermetallic was also observed, depending on subsequent controlled cooling. [ABSTRACT FROM AUTHOR]

An UPLC–Orbitrap MS system was exploited to develop and validate a method for the simultaneous determination of 11 water-soluble azo dyes (Acid Yellow 17, Acid Red 14, Acid Red 26, Acid Red 73, Acid Orange 52, Acid Orange 7, Acid Orange 12, Acid Yellow 36, Acid Orange 5, Acid Red 88 and Acid Red 9) in soft drinks. Three pairs of isomers and four disulphonated azo dyes were among a total of 11 water-soluble azo dyes obtained and purified using an SPE cartridge. They were well separated using optimized UPLC conditions with a RP18 column and a MS detector with a compatible mobile phase system. All these dyes were detected by the Orbitrap XL mass spectrometer in negative ion mode. HCD tandem MS fragment ions are first reported in this paper, and these fragment ions can be used for identification of isomers of azo dyes. According to SANCO/10684/2009, one quasi-molecular ion in full scan mode as quantification ion and one or two HCD tandem MS fragment ions as identification ions are required for compound confirmation. Matrix-matched calibration was employed for quantification. The linear matrix-matched calibration for the 11 dyes was in the range 5–200 ng g−1 with correlation coefficients (r) of 0.9939–0.9988. Recoveries were 68.9–110.8% with coefficients of variation of 0.9–12.0%. Depending on the dye and matrix involved, the LODs were between 1.0 and 3.2 ng g−1 and LOQs were between 5.2 and 9.8 ng g−1. [ABSTRACT FROM AUTHOR]

The physiological and biochemical responses of ryegrass (Lolium multiflorum) to PAH induced stress in soils contaminated with phenanthrene and pyene were investigated, in the presence of PAH-degrading bacteria (Acinetobacteria junii) or arbuscular mycorrhizal fungi (AM fungi, Glomus mossae). The parameters monitored included chlorophyll content, chlorophyll a/b ratio, soluble-carbohydrate content, soluble-protein, malondialdehyde and electrolyte leakage, and superoxide dismutase (SOD) and peroxidase (POD) activities. Ryegrass showed good resistance and acclimation to PAH stress in soil, however, PAH contamination resulted in adverse effects such as damage of photosynthetic function and acceleration of shoot senescence. At PAH level of 100 mg kg-1, chlorophyll contents were 14% lower than control (no PAH). Activities of SOD and POD were more sensitive indicators of PAH stress as compared to other parameters. However, all parameters showed trends based on either the bioaugmentation of the plants or PAH treatment level. It was concluded that the inoculation of AMF and PAH-degrading bacteria, especially the former, have a positive effect on alleviation of PAH toxicity to ryegrass plants. Furthermore, the inoculation of AMF increased the shoot and biomass of ryegrass by 11-19% and 18-78%, respectively. Bioaugmented ryegrass plants show promise as a host plants in the phytoremediation of PAH contaminated soils. [ABSTRACT FROM AUTHOR]

Ab initio calculations ascertain that the difference of formation enthalpy between order and disordered Cu3Au phases is at least 0.044 eV per atom. The calculations also suggest that the tetrahedral clustering configuration and its spatial distribution have drastic effect on the formation enthalpy of the disordered structure and that segregation of the Au atoms significantly lowers the formation enthalpy of the disordered phases. [ABSTRACT FROM AUTHOR]

Phenanthrene (Phe) and pyrene (Pyr) are two typical polycyclic aromatic hydrocarbons (PAHs) found in contaminated soil. This study investigated physiological and biochemical responses of rice (Oryza sativa L.) to PAH stress after they were planted in soils contaminated with Phe and Pyr, in the presence or absence of a PAH-degrading bacteria (Acinetobacteria sp.). A number of parameters including biomass and water, chlorophyll and chlorophyll a/b ratio, electrolyte leakage, activities of superoxide dismutase (SOD) and peroxidase, and soluble carbohydrate and soluble protein contents were monitored. Results show that rice plants have good resistance and tolerance to lower levels of PAHs stress, while adding high levels of PAHs to soils resulted in adverse effects on rice plants such as a reduction in biomass and damage to photosynthetic function. Water content and SOD activities were the most sensitive indicators of PAH stress among the observed parameters. Inoculation with PAH-degrading bacteria promoted growth and photosynthesis of rice. [ABSTRACT FROM AUTHOR]