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AbstractDifferent pile penetration methods will cause different pile penetration results. Therefore, it is very necessary to study the pile penetration mechanism under different pile penetration methods. In this paper, numerical simulations using the discrete element method (DEM) are carried out to investigate the meso-scopic mechanism of pipe pile penetration under jacking and driving methods. The mechanism is comprehensively compared and analyzed in terms of particle movement, changes in the force chain, displacement changes, resistance of penetration pile, soil lateral stress and soil vertical stress. Results show that the height of the soil plug in the jacked pile is lower than that in the driven pile. The degree of contact force chain at the bottom of the soil plug in the driven pile is slightly higher than that at the bottom of the soil plug in the pile of the jacked pile. The total resistance of the driven pile greater than that of the jacked pile. Within a certain distance below the pile tip, the jacked pile affects the vertical stresses of the soil in this area to a greater extent than the driven pile. Then, parametric sensitivity analysis is performed, which captures the effects of the penetration velocity in the jacking method and the hammering frequency in the driving method. This study can provide a reference for the selection of the penetration method of pipe piles in actual projects. [ABSTRACT FROM AUTHOR]

A linear parallel bond model combined with Weibull distribution to take into account the mechanical heterogeneity of brittle rocks is used to investigate the cracking behavior, acoustic emission (AE) characteristics and full-field stress evolution of rocks containing three parallel pre-existing flaws under uniaxial compression. The intact model is calibrated to the macro mechanical properties of rocks obtained from laboratory tests. The numerical results indicate that the presence of three parallel pre-existing flaws weakens the mechanical properties of rocks. As the flaw inclination increases, uniaxial compression strength shows a trend of first decreasing and then increasing, and the elastic modulus and Poisson's ratio are roughly increasing. The displacement localization zones chronologically formed around pre-existing flaws can interact with each other, and the damage or fracture processes of pre-cracked samples are complicated. And the tensile stress in x direction concentrates around pre-existing flaws. As the flaw inclination increases, the tensile stress concentration area at the end of the pre-existing flaws in the x direction also changes, at the same time, the area of the tensile stress concentration area in the y direction gradually decreases. And AE events with high fracture intensity are located in the macroscopic shear zone or split zone. [ABSTRACT FROM AUTHOR]

The purpose of this study was to explore the possible association between dairy and NCDs and identify possible dairy types that could lower the odds of NCDs. Data were from the 2003–2016 NHANES, a cross-sectional study with 20,297 adults. Multivariable logistic regression analyses and restricted cubic spline (RCS) models were conducted. In the highest intake group (>250 g/d, 1 daily serving), yogurt and milk were inversely associated with the odds of general obesity and central obesity [OR (95% CI), general obesity, 0.74 (0.60–0.91) and 0.75 (0.68–0.83); central obesity, 0.70 (0.56–0.87), and 0.77 (0.70–0.86), respectively, p < 0.05]. Higher milk intake is inversely associated with diabetes, and higher cream intake is associated with a lower likelihood of hyperlipidaemia. The intake of yogurt, milk, cheese, and butter was 0–308 g/d (0–1.2 daily servings), 0–887 g/d (0–3.5 daily servings), <75 g/d (1.7 daily servings), and <15 g/d (0.5 daily servings), respectively. [ABSTRACT FROM AUTHOR]

The objective of this study is to investigate the fracturing characteristics of granite under impact loading. Generation and propagation of cracks from the specimen edge subjected directly to impact loading were captured by the ultrahigh-speed photography. Testing results indicate the existence of a critical impact velocity. At an impact velocity lower than the critical impact velocity, a damage zone will be generated on the edge subjected directly to impact and the damage zone area is varied, depending on the magnitude of impact velocity. At an impact velocity greater than the critical impact velocity, radial cracks appear on the boundary of the damage zone and propagate deep into the rock plate with further increasing impact velocity. The increases in radial crack length and damage zone area are affected by impact velocity and impact angle. However, at some impact velocity, damage zone area decreases while radial crack length increases, demonstrating the existence of an incubation period of crack forming. Comparison between testing and numerical results shows that at a constant impact velocity the fractured zone area and the crater depth are varied, depending on impact angle. The results are helpful to understand the fracturing process in rock subjected to impact loading. [ABSTRACT FROM AUTHOR]

The data type and quantity of user load data show an exponential growth, so that the traditional load forecasting methods can hardly meet the load forecasting requirements of massive users. Aiming at this problem, a parallel OS-ELM short-term load forecasting model based on Spark is proposed in this article. By analyzing the characteristics of the Spark framework and the MapReduce framework, the Spark big data processing framework is determined as the basic framework for processing massive user load data, and a parallel K-means load clustering model based on Spark is designed. The on-line sequential learning machine OS-ELM makes the hidden layer data of computing each incremental training dataset mutually independent, therefore, a Spark-based parallel OS-ELM (SBPOS-ELM) algorithm is put forward. The proposed model is applied under the smart electricity big data environment and the training samples are selected using the incremental training dataset to make a short-term prediction of the millions of users' smart meter electricity load, which verifies the feasibility and effectiveness of the proposed model. At last, comparing with other commonly used short-term load forecasting algorithms, the experimental results show that SBPOS-ELM algorithm has higher accuracy and operation efficiency. [ABSTRACT FROM AUTHOR]

AbstractThe pile-caisson composite structure (PCCS) is an innovative underground anchorage foundation used to support large-span suspension bridges. This paper presents the displacement and the load transfer mechanism of the PCCS. The bearing responses of each individual pile in the PCCS were analyzed employing the finite element method, which was verified by the model test results. The peak bending moments borne by pile P11 and pile P53 in the PCCS exhibit the most significant disparity, with a difference that can reach up to 133.97%. Moreover, a parametric study utilizing numerical simulations indicates that augmenting the pile diameter and length, while reducing the pile spacing, can mitigate the displacements of the PCCS. However, there is an upper limit (i.e. S = 3.5d) for the pile spacing beyond which marginal benefits could be obtained. The findings of this study can provide guidance for the design and construction of the PCCS. [ABSTRACT FROM AUTHOR]

A kind of bacteria secreting cellulase and showing probiotic attributes was isolated from the cecum of goose and identified asBacillus amyloliquefaciensby analysis of 16S rRNA gene sequence and named asB. amyloliquefaciensS1.In vitroassays, the enzymatic activity of the strain was determined by the reducing-sugar method, and the proper culture conditions of producing cellulase and some properties of the cellulase were investigated. The cultural mixture of the bacteria had a high cellulase activity of 1.25 U/mL. In order to improve the utilization rate of the cellulase, some properties of the cellulase were studied. The best reaction pH of the enzymes was 7.0 and the optimum reaction temperature was 60°C. The enzyme was a kind of neutral cellulase that possessing strong resistance against heat and acidity. It showed high activity to absorbent cotton, soybean meal, and filter paper. Meanwhile, a gene encoding a kind of cellulase was cloned and prokaryotic expressed inEscherichia coli. The gene had 1500 bp in length, encoding a protein of 55 kDa, which was confirmed by SDS-PAGE and Western blotting. This study explored the possibility of degrading ability of bacteria with its probiotic attributes to enhance digestibility of the feed and gut health of animal. It also provided some basis for its further functional analysis and practical application as a microbial preparation for the breeding. [ABSTRACT FROM AUTHOR]

The objective of this experiment was to determine the digestible energy (DE) and metabolisable energy (ME) in 22 sources of soybean meal (SBM) produced from soybeans from different countries and subsequently to establish equations for predicting the DE and ME in SBM based on their chemical composition. The 22 sources of SBM were all processed in Chinese crushing plants, but the soybeans used originated from China (n = 6), the US (n = 6), Brazil (n = 7) or Argentina (n = 3). The basal diet was a corn-based diet and 22 additional diets were formulated by mixing corn and 24.3% of each source of SBM. The average DE and ME in SBM from China, the US, Brazil and Argentina were 15.73, 15.93, 15.64 and 15.90 MJ/kg and 15.10, 15.31, 14.97 and 15.42 MJ/kg, respectively, and no differences among countries were observed. From a stepwise regression analysis, a series of DE and ME prediction equations were generated. The best-fit equations for SBM were DE = 38.44–0.43 crude fibre −0.98 gross energy +0.11 acid detergent fibre (R2 = 0.67,p < 0.01) and ME = 2.74 + 0.97 DE −0.06 crude protein (R2 = 0.79,p < 0.01). In conclusion, there were no differences in the DE and ME of SBM among the different soybean sources used in this experiment. The DE and ME of SBM of different origin can be predicted based on their chemical composition when fed to growing pigs. [ABSTRACT FROM AUTHOR]

To study the acute toxic effects of PCBs on airway exposure, the cell viability, apoptosis and mitochondrial functions of human lung cancer cell line A549 were measured and compared after Aroclor 1254 exposure for different time. The results showed that Aroclor 1254 could inhibit cell viability and increase cell apoptosis in a concentration- and time-dependent manner. The mitochondrial apoptosis pathway was confirmed playing an important role. ROS elevation was an early response within 1h treatment of Aroclor 1254. Then after 4 h of Aroclor 1254 exposure, the intracellular calcium level increased and mitochondrial transmembrane potential (ΔΨm) collapsed, accompanying with Cytochromec(Cyt-c) leakage, boosting expression of Bax, Apaf-1 and miRNA155, which were involved in the mitochondrial apoptosis pathway. After 24 h of Aroclor 1254 exposure, ROS returned to normal level, but cell apoptosis rate was higher than that at 4 h with ΔΨmcontinued collapsing and intracellular calcium increased. In conclusion, Aroclor 1254 could suppress cell viability and induce apoptosis in A549 cells, which was associated with ROS over-production and elevated cellular Ca2+level, which may result in mitochondrial dysfunction, inducing expression of Bax/Cyt-c/Apaf-1 and miRNA155. [ABSTRACT FROM AUTHOR]