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A coupled total Lagrangian (TL) and weakly compressible (WC) smoothed particle hydrodynamics (SPH) method is presented to model three-dimensional fluid–structure interactions (FSI) with deformable structures. In the coupled TL–WC SPH, the fluid phase is simulated using WCSPH, while the structure solver is based on TLSPH. The three main deficiencies of solid simulation using conventional SPH, i.e. inconsistency, tensile instability and hourglass mode are circumvented in the stabilized TLSPH by means of corrected kernel gradient, Lagrangian kernel function and hourglass control technique, respectively. The resulted stabilized TLSPH is stable, accurate and has almost quadratic convergence rate in solid modeling. To increase the accuracy in FSI modeling, the δ − SPH technique is employed to improve the pressure results in the fluid phase. Based on the Adami boundary condition (Adami et al., 2012), a unified framework for modeling solid boundaries and the fluid–structure interfaces is presented. Furthermore, the GPU parallelization is employed to accelerate the proposed TL–WC SPH method for higher efficiency. The coupled method is employed to simulate problems of pure fluid flow, elastic solids with large deformation and fluid–structure interaction with deformable structures. The numerical results are compared with analytical solutions and results from literature. The GPU efficiency and speed-up compared with CPU implementations are analyzed. The novelty of this work consists: (1) three-dimensional SPH modeling of FSI problems with deformable structures, (2) stabilized structure simulation free of hourglass mode, (3) a unified framework for FSI problems taking advantages of δ -SPH, TLSPH, hourglass control, and GPU acceleration. Importantly, with the hourglass control technique proposed by Ganzenmuller (2015), stresses can be captured accurately in the TL–WC SPH-based FSI simulations.

Lithium-sulfur batteries have emerged as extraordinarily favorable energy storage devices due to their high specific capacity and energy density, safety and low cost. Unfortunately, the wide applications of lithium-sulfur batteries are hampered by several issues, such as the low electronic conductivity and slow redox kinetics, serious volumetric expansion and polysulfide “shuttle effect”. To overcome these issues, in our work, we design and synthesize a composite sulfur host material of Co9S8 microspheres and N-doped carbon nanotubes, where the metallic sulfide Co9S8 with a good conductivity enables the immobilization of the polar lithium polysulfides owing to the strong polar chemisorptive capability, and the one dimensional N-doped carbon nanotubes can provide channels for fast electron and lithium-ion transport. As the lithium polysulfides are well confined, and the redox conversions are promoted, the Co9S8@N-CNTs/S-based lithium-sulfur battery possesses a superior energy storage performance, exhibiting a large specific capacity of 1233 mAh g−1 at 0.1 C and an outstanding cyclic performance, with a low decay of 0.045% per cycle and a Coulombic efficiency of more than 99% after 1000 cycles.

IMPORTANCE: High salt intake is associated with hypertension, which is a leading modifiable risk factor for cardiovascular disease. OBJECTIVE: To assess the association of a government-led, multisectoral, and population-based intervention with reduced salt intake and blood pressure in Shandong Province, China. DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study used data from the Shandong–Ministry of Health Action on Salt and Hypertension (SMASH) program, a 5-year intervention to reduce sodium consumption in Shandong Province, China. Two representative samples of adults (aged 18-69 years) were surveyed in 2011 (15 350 preintervention participants) and 2016 (16 490 postintervention participants) to examine changes in blood pressure, and knowledge, attitudes, and behaviors related to sodium intake. Urine samples were collected from random subsamples (2024 preintervention participants and 1675 postintervention participants) for measuring sodium and potassium excretion. Data were analyzed from January 20, 2017, to April 9, 2019. INTERVENTIONS: Media campaigns, distribution of scaled salt spoons, promotion of low-sodium products in markets and restaurants, and activities to support household sodium reduction and school-based sodium reduction education. MAIN OUTCOMES AND MEASURES: The primary outcome was change in urinary sodium excretion. Secondary outcomes were changes in potassium excretion, blood pressure, and knowledge, attitudes, and behaviors. Outcomes were adjusted for likely confounders. Means (95% CIs) and percentages were weighted. RESULTS: Among 15 350 participants in 2011, 7683 (50.4%) were men and the mean age was 40.7 years (95% CI, 40.2-41.2 years); among 16 490 participants in 2016, 8077 (50.7%) were men and the mean age was 42.8 years (95% CI, 42.5-43.1 years). Among participants with 24-hour urine samples, 1060 (51.8%) were men and the mean age was 40.9 years (95% CI, 40.5-41.3 years) in 2011 and 836 (50.7%) were men and the mean age was 40.7 years (95% CI, 40.1-41.4 years) in 2016. The 24-hour urinary sodium excretion decreased 25% from 5338 mg per day (95% CI, 5065-5612 mg per day) in 2011 to 4013 mg per day (95% CI, 3837-4190 mg per day) in 2016 (P

Due to huge bulk volume and extremely complex geometrical and geological features, it is forbiddingly difficult to perform a dam structural analysis with even moderate geometry fidelity in engineering practices. We present a high resolution of engineering structural analysis of the first ultra-high concrete-faced rockfill dam in China. Mesh resolution is taken to be 20 cm along slab thickness for the bulk volume of 20M $$\hbox {m}^{3}$$ of the whole dam. The engineering problem is solved by considering nonlinear behaviors such as joints’ contact nonlinearity, creep deformation, and strong thermo-mechanical coupling, as well as blended continuous-discontinuous approximation, on a mesh model of 1.1 billion dofs using 16K CPU cores of Tianhe-II. The problem to be solved is a challenging non-positive definite, non-symmetric and ill-conditioned matrix problem. The simulation confirms in the first time that the sunlight temperature effect can contribute up to a contact stress increment of maximum 10.9 MPa and explains frequent extrusion damage observed for the dam. As model tests are difficult to perform for high dams, with this first success, we envision that extreme-scale simulation would pose broad impact on the safety evaluation of high dams in future.

Extrusion damage in the concrete face was widely observed in high concrete-faced rockfill dams in the last two decades. However, the accurate estimation of the concrete stress remains a great challenge. In this paper, a thermo-mechanical coupling method is presented to numerically evaluate the solar radiation effect on the concrete stress within the dual mortar finite element framework. The heat conduction is modelled as a transient time-dependent equation and hence the heat flow can be determined by meteorological data. The thermo-mechanical coupling is conducted in a weak way such that the linear system can be split into two subsystems friendly to the linear solver. The present method based on using nonconforming meshes is validated by the comparisons with node-to-segment method, conforming mesh and analytical solution. The application to a concrete-faced rockfill dam indicates that the phase lag and amplitude damping effects are apparent in the thermal analysis, confirming the importance of using transient heat conduction theory. The observed slab-slab separations emphasis the importance of using dual mortar contact method. The thermal stress is found to be larger than 10 MPa and therefore needs to be considered in the design and safety assessment.

In this paper, a flow model for avalanches based on the three-dimensional yield criterion is presented in an attempt to allow the relaxation of the assumption of lateral confinement pressure that is adopted in the traditional three-dimensional Savage–Hutter model (S–H model). One of the advantages of this model is that a simplified constitutive relationship for granular flow, which could reveal the internal mechanism of avalanches, is adopted. Additionally, another advantage is that the strength parameters used in the proposed model are readily available for natural materials. The flow properties of avalanches are influenced by the generalized friction coefficient, which is a parameter that can be assessed by introducing the three-dimensional yield criterion. By comparing the results obtained by numerical simulations using the model proposed in this paper and laboratory experiments, a reasonably good agreement can be reached with regard to the prediction of the moving process of avalanches.

Conventional two-field mortar methods have master/slave bias and need special treatments for the cross corner problem. In this work, we present a three-field dual mortar method, which employs an intermediate interface to connect individual subdomains with nonconforming meshes. Using this intermediate interface as the master face, a dual mortar method can be formulated by discretizing Lagrange multipliers on the subdomain interfaces using dual basis functions. Furthermore, the computational cost is minimized by static condensation of Lagrange multipliers and elimination of displacement unknowns on subdomain interfaces. Owing to the three-field formulation, the presented method is free of master/slave bias and can handle the cross corner problem naturally. The stability condition for the intermediate interface mesh is investigated by theoretical analysing and numerical modelling. Numerical tests show that the presented method has optimal convergence rate and allows great flexibility in mesh preparation.

In terms of \(L_{1/2}\) regularization, a novel feature selection method for a neural framework model has been developed in this paper. Due to the non-convex, non-smooth and non-Lipschitz characteristics of \(L_{1/2}\) regularizer, it is difficult to directly employ the gradient descent method in training multilayer perceptron neural networks. A smoothing technique has been considered to approximate the original \(L_{1/2}\) regularizer. The proposed method is a two-stage updating approach. First, a multilayer network model with smoothing \(L_{1/2}\) regularizer is trained to eliminate the unimportant features. Second, the compact model without regularization has been simulated until there is no improvements for the performance. The experiments demonstrate that the presented algorithm significantly reduces the redundant features while keeps a considerable model accuracy.

The variation of stress–strain state induces changes in the permeability of clayey soil and then affects the properties of seepage and consolidation. In previous studies, variations of the permeability of soil in shear process were mainly neglected, and there were no reasonable descriptions of the permeability in such a condition. To study the variation of the hydraulic conductivity of clayey soil in shear process, new triaxial seepage equipment was designed by changing the conventional triaxial apparatus. Based on a series of tests under different confining pressures carried out by this equipment, the influences of the stress–strain state of clayey soil on hydraulic conductivity were investigated. Furthermore, a mathematical model for the hydraulic conductivity of clayey soil under the condition of large shear deformation was proposed. The comparison between the seepage test results and the calculated values of the proposed model indicates that the mathematical model can calibrate the effects of ...

A consolidation analysis method for an earth-rockfill dam based on the coupling of physical state, stress deformation, and seepage was established. In this method, a permeability coefficient model considering physical state and shear stress level was introduced, and it was integrated with Biot’s consolidation theory to simulate the coupling relationship. Taking the Nuozhadu high earth-rockfill dam as an example, a parameter back-analysis method using a neural network and evolutionary algorithm was applied to back-analyze the permeability coefficient model parameters of the core material based on observation data of pore water pressure in the dam. Then, consolidation numerical analyses were performed by using the back-analyzed parameters and the constant permeability measured in situ, respectively. The spatial and temporal distribution of pore water pressure calculated by the back-analyzed parameters coincided quite well with the monitoring data during construction and operation. However, the numer...