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Under various stress paths, the deformation characteristics represented great differences. In this paper, a series of cyclic triaxial tests have been conducted with Fujian standard sand. By comparing the constant deviatoric (CDS) and constant axial stress paths (CAS), the influence mechanism of the cyclic amplitude of the deviatoric stress was discussed. The test results showed that the stress path significantly influenced the volumetric and shear strains. The increasing and decreasing trend in the volumetric strain (ɛv) was consistent with the spherical stress (lnp). Compared with the two stress paths, the slope of the ɛv−lnp curve during the loading and unloading stages was larger under the CAS path. In the CDS path, qc almost did not affect the cumulative volumetric strain, and in the CAS path, the effect was obvious. The shear strain curve was in accordance with the direction of the stress path. As the cyclic number increased, the shear strain gradually accumulated. The shear strain accumulation under the CAS path was larger. The shear strain largely depended on the relative position between the critical state line (CSL) and the stress state of the soil during cyclic loading and unloading. Practical Applications: In practical engineering, the soil will experience various stress paths. For example, in slope or earth–rock dam engineering, where the water level rises and falls repeatedly, the soil often goes through the stress path of constant deviational stress with the cyclic increase and decrease in the spherical stress. In foundation pit engineering, the soil often experiences the stress path of the constant axial stress (CAS) with cyclic loading and unloading of the lateral stress. The stress path greatly influences the deformation and strength of soil. Therefore, the previous two stress paths are compared in this paper to discuss the influence of the cyclic amplitude of deviatoric stress. Under three different consolidation states, the cyclic amplitude of the deviatoric stress significantly influenced the volumetric and shear strains. The shear strain largely depended on the relative position between the critical state line (CSL) and the stress state of the soil during cyclic loading and unloading. Therefore, in practical engineering, if the stress path in the experiment differs from the actual value, the influence of the stress path should be properly considered. The results should be modified according to the degree of influence of each stress condition. [ABSTRACT FROM AUTHOR]

The composition of high rockfill dam materials is complex, and the mechanical parameters are uncertain and correlated in unknown ways due to the influences of the environment and construction, leading to complex deformation mechanisms in the dam–foundation system. Statistical characteristics of material parameters are the basis for deformation and stress analysis of high core rockfill dams, and using an inaccurate distribution model may result in erroneous analysis results. Furthermore, empirically evaluated distribution types of parameters are susceptible to the influence of small sample sizes, which are common in the statistics of geotechnical engineering. Therefore, proposing a multi-dimensional joint distribution model for parameters based on small-sample data is of great importance. This study determined the interval estimation values of Duncan–Chang E-B model parameters—such as the mean value and coefficient of variation for the core wall, rockfill, and overburden materials—using parameter statistical analysis, bootstrap sampling methods, and Akaike information criterion (AIC) optimization. Additionally, the marginal distribution types of each parameter were identified. Subsequently, a multi-dimensional joint distribution model for Duncan–Chang model parameters was constructed based on the multi-dimensional nonlinear correlation analysis of parameters and the Copula function theory. The application results for the PB dam demonstrate that joint sampling can effectively reflect the inherent correlation laws of material parameters, and that the results for stress and deformation are reasonable, leading to a sound evaluation of the cracking risk in the core wall of high core rockfill dams. [ABSTRACT FROM AUTHOR]

Surface ozone (O 3) is the primary air pollutant threatening global vegetation. It typically reduces the photosynthetic rate and stomatal conductance, leading to changes in carbon, water, and energy cycles; vegetation structure and composition; and climate. Several parameterization schemes have been developed to integrate the photosynthetic and stomatal responses to O 3 exposure in regional and global process-based models to simulate time- and space-varying O 3 plant damage and its cascading dynamic influence. However, these schemes are calibrated based on limited observations and often fail to reproduce the response relationships in observations, impeding accurate assessments of the role of O 3 plant damage in the Earth system. This study proposes a new parameterization scheme to utilize the extensive observations from O 3 fumigation experiments to inform large-scale modeling. It is built on 4210 paired data points of photosynthetic and stomatal responses compiled from the peer-reviewed literature, more than 6 times larger than those employed in earlier schemes. Functions of phytotoxic O 3 dose (POD) are found to accurately reproduce the statistically significant linear or nonlinear relationships observed between POD and either relative leaf photosynthetic rate or relative stomatal conductance for needleleaf trees, broadleaf trees, shrubs, grasses, and crops. These eliminate the practice in earlier schemes of setting response functions as constants and applying the response function from one vegetation type to another. It outperforms the old scheme in the Community Land Model (CLM), which skillfully reproduces the observed response for crop photosynthetic rate only. The nonlinear response functions we developed depict decreasing plant sensitivity with increases in POD, enabling models to implicitly capture the variability in plant ozone tolerance and the shift among plant species for both intra- and inter-PFTs (plant functional types) within a vegetation type observed in the real world. Then, the new scheme is incorporated into the Community Earth System Model version 2.2 (CESM2.2), specifically its land component CLM5, to quantify the global impacts of present-day O 3 plant damage by comparing the simulations with and without O 3 plant damage. Results show that O 3 exposure reduces the global leaf photosynthetic rate by 8.5 % and stomatal conductance by 7.4 %, around half the estimates using the old scheme. Furthermore, the new scheme improves global gross primary productivity (GPP) simulations, decreasing RMSE by 11.1 % relative to simulations without O 3 plant damage and by 11.7 % compared to the old scheme. These results underscore the importance of including O 3 plant damage in large-scale process-based models and the effectiveness of the new scheme in assessing and projecting globally the role of O 3 plant damage in the Earth system. [ABSTRACT FROM AUTHOR]

How obesity and elevated androgen levels in women with polycystic ovary syndrome (PCOS) affect their offspring is unclear. In a Swedish nationwide register-based cohort and a clinical case-control study from Chile, we found that daughters of mothers with PCOS were more likely to be diagnosed with PCOS. Furthermore, female mice (F.sub.0) with PCOS-like traits induced by late-gestation injection of dihydrotestosterone, with and without obesity, produced female F.sub.1-F.sub.3 offspring with PCOS-like reproductive and metabolic phenotypes. Sequencing of single metaphase II oocytes from F.sub.1-F.sub.3 offspring revealed common and unique altered gene expression across all generations. Notably, four genes were also differentially expressed in serum samples from daughters in the case-control study and unrelated women with PCOS. Our findings provide evidence of transgenerational effects in female offspring of mothers with PCOS and identify possible candidate genes for the prediction of a PCOS phenotype in future generations. Prenatal androgen exposure causes transgenerational increases in offspring susceptibility to polycystic ovary syndrome in adulthood., Author(s): Sanjiv Risal [sup.1] , Yu Pei [sup.1] [sup.2] , Haojiang Lu [sup.1] , Maria Manti [sup.1] , Romina Fornes [sup.1] , Han-Pin Pui [sup.1] , Zhiyi Zhao [sup.1] [sup.3] [...]

The precipitate phases of electron beam welded joint in GH141/GH907 superalloy dissimilar materials were studied by scanning electron microscopy (SEM), transmission electron microscope (TEM) and energy dispersive spectrometer (EDS). The welded joint contains GH141 heat affected zone, GH907 heat affected zone and weld area. The results indicate that there is no new precipitate phase in the heat affected zones of electron beam welding. Under the current heat treatment process, the precipitate phases of GH141 heat affected zone are square granular γ′ phases which are covered in matrix densely, thick massive MC type carbides with random distribution and the M6C type carbides which are precipitated mostly in the grain boundaries. Precipitate phases of GH907 heat affected zone are needle shaped ε phases covered in matrix densely and block G phases Nb3Ni2Si which are dispersed distribution. Precipitate phases of weld area are different from the two kinds of welding materials. One of them is a new needle shaped phase which has parallel or staggered distribution, and the other one is a tiny square or ellipsoid granular new precipitate phase which is proved to be orthogonal crystal system NbTi4 phase.

The external stress will change the transformation process and microstructure of the material, and the residual stress generated during the processing of the material will also affect the transformation. Herein, the effect of residual stress is simulated by applying uniaxial elastic loads during the continuous cooling of high‐strength low‐alloy hot‐rolled strip. The transformation process and microstructure of the samples under different stress conditions are investigated. The results show that residual stress can accelerate the transformation process, and the tensile stress is greater than the compressive stress. The degree of lattice mismatch in stressed samples is larger than that in unstressed samples, leading to dislocation proliferation. It is found that there is a phenomenon of residual stress‐induced grain growth according to the statistics of grain size of different samples. Due to the higher dislocation density and smaller curvature of the parent phase interface under compressive stress, the compressive stress samples have a higher nucleation rate, resulting in smaller grain size than the tensile stress samples. In addition, the transformation texture also changes under residual stress. [ABSTRACT FROM AUTHOR]

The widely distributed loess–mudstone strata structure in the Loess Plateau of China is one of the fundamental reasons for the susceptibility and group occurrence of seismic landslides in the area. This study took the loess landslides induced by the Haiyuan earthquake as a case study. Through extensive field investigations, the loess cover thickness, mudstone dip angle, slope height, and slope angle were chosen as the influencing factors. Together with mathematical statistics and geotechnical tests, two models, one of a loess–mudstone slope and the other of a pure loess slope, were constructed. Their seismic stabilities under different slope angles and slope heights were compared to analyze the influence of the underlying mudstone strata on the loess slope seismic stability. Meanwhile, a sensitivity analysis of these strata factors affecting the seismic stability of the loess–mudstone slope was carried out based on the orthogonal test. The results showed that ignoring the underlying mudstone strata would lead to smaller calculation results than the actual situation. The sensitivity influence of the factors on the loess–mudstone slope seismic stability comprised the slope angle, loess cover thickness, slope height, and mudstone dip angle from high to low. [ABSTRACT FROM AUTHOR]