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To observe anatomic relationships between lumbar bicortical pedicle screws (BPSs) at 2 sagittal section angles (SSAs) and lumbar artery (LA).We observed 2 SSAs, vertical angle and cephalic angle, of the BPS. The positions at which the BPS breaks through the anterior vertebral cortex were defined as point A and point B. Distances from point A and point B to LAs were measured. The percentage of risk of injury to LAs was calculated according to these distances.At the same transverse section angle on the left and right side in L1 and L2, distance from point A to LA was significantly greater than distance from point B to LA (P0.001) except at a transverse section angle of 0° on the right side in L2 (P0.05). At the same transverse section angle on the left in L3 and L4, distance from point B to LA was significantly greater than distance from point A to LA (P0.001). The percentages of high risk of injury to the LA resulting from BPSs at the vertical angle in L1 and L2 were 0%-6.2%. The percentages of high risk of injury to the LA resulting from BPSs at the cephalic angle on the left side in L3 and L4 were 0%-18.5%.Lumbar BPSs present a risk of injury to the LA. The vertical angle is the recommended SSA for BPSs in L1 and L2, and the cephalic angle is the recommended SSA in L3 and L4.

Polymeric high-voltage direct-current (HVDC) cables are the core equipment in energy internet, which enable the long-distance large-capacity electric power transmission, large-scale utilization of renewable electric power and flexible interconnection of large power grids. Performance of the HVDC cables are determined by the properties of their insulation material. However, the traditional polymeric HVDC cable insulation material, crosslinking polyethylene (XLPE) is limited to relatively low working temperature which restricts the power capacity of HVDC cables. XLPE with thermosetting characteristics also presents a major barrier to material recycling and environmental pollution reduction. Here we report the ternary nanocomposites of polypropylene (PP), thermoplastic polyolefin (TPO) and MgO nanoparticles as an efficient way to recyclable HVDC cable insulation material that simultaneously possess excellent thermal, mechanical and electrical properties, especially at high temperatures. At an optimal composition, the ternary nanocomposites integrate the complementary properties of the multi-components to raise the mechanical flexibility at room temperature and greatly improve the electrical properties at high temperatures (including suppressed space charge accumulation and increased breakdown strength and volume resistivity) while retaining high melting temperature comparable to PP of about 160 °C. This work may pave a way for synergistic optimization of the overall properties of insulation materials and enabling the successful development of recyclable insulation material for large-capacity HVDC cable application.

Due to its favorable properties of low core loss and high saturation magnetic flux density, amorphous material is widely used as the core material of low and medium frequency transformers. However, its magnetostriction is much higher than that of grain-oriented sheet steel, a very common material for conventional transformers, resulting in high acoustic noises. This paper proposes a comprehensive model of magnetostriction in amorphous material based on the interdependence between magnetostriction and magnetization by combining the isotropic magnetostriction effect and Jiles-Atherton energy balance theory. Incorporated in coupled magneto-mechanical field calculation, the proposed model can correctly simulate the butterfly loops of magnetostriction, magnetic hysteresis loops and vibration displacements. The theoretical results of magnetostriction characteristic are verified by both single sheet test and the experimental results of amorphous transformer prototype.

Magnetite near-infrared (NIR) photocatalysts with upconversion properties are put forward to meet the requirements of high solar energy utilization efficiency and sustainability based on the resource utilization of electroplating wastewater (EPW). The Ca–Zn magnetite precursor (CZ) was initially prepared from the mixed-ferrites (M-Fe3O4) produced from EPW and the photocatalyst (Zn2+) and upconversion host material (Ca2+)-related metal ions included in EPW and its effluents. With the addition of lanthanides and F− ions, a novel magnetite NIR photocatalyst of Er3+/Tm3+/Yb3+-(CaF2/ZnFe2O4/ZnO) (ETY-FCZ) was further synthesized. In the crystal phases of ETY-FCZ, (Ca0.8Yb0.2)F2.2 is used as the upconversion host material for Er3+/Tm3+/Yb3+ ions. The magnetic agents including ZnFe2O4 display the heterojunction with ZnO, as well as the broadband spectrum utilization property for ETY-FCZ. ETY-FCZ possesses efficient electron-hole pair separation ability, and all the upconversion luminescence emitted from ETY-FCZ can be absorbed for photocatalysis, which result in higher removal rates of methyl orange and salicylic acid compared to those of CZ. ETY-FCZ is an excellent magnetite NIR photocatalysts with magnetic recycling performance, and it has promising applications in the reuse of EPW and the wastewater treatment.

Pollutants removal and genetic responses of simultaneous heterotrophic nitrification and aerobic denitrification (SHNAD) treating seawater-based wastewater were studied under ampicillin stress. Marine SHAND bacteria exhibited good tolerance to 10 mg/L ampicillin with nitrogen removal efficiency and organics removal efficiency of 94.5% and 82.6%, respectively. Besides, the half-inhibitory concentration of ampicillin on marine SHAND bacteria was 50 mg/L. The relative abundances of antibiotic resistance genes (ARGs) first decreased and then increased with ampicillin addition. The blaVIM played an important role to resist 25 mg/L ampicillin, which contributed to the recovery of pollutants removal. BlaSHV and blaTEM dominated ARG subtypes, which accounted for 96.6% of ARGs abundance. At 50 mg/L ampicillin, reactive oxygen species (ROS) production and cell numbers of apoptosis increased by 47.9% and 367.5%, respectively. The overproduction of ROS was stimulated by ampicillin, which caused bacterial cell apoptosis. Marine SHNAD bacteria produced more extracellular polymeric substances to resist ampicillin.

Recently, viscoelastic surfactant (VES) fracturing fluids have attracted wide attention because they are highly viscoelastic and environmentally benign. To optimize fracturing fluid formulations for coal reservoir conditions, 135 groups of VES fracturing fluids were prepared. The influence of the cationic surfactant’s hydrocarbon chain lengths on water loss, wettability, viscosity, and temperature resistance were analyzed. To further improve the surfactant’s aggregation capabilities, zwitterionic surfactants were added to fracturing fluids prepared with stearyl trimethyl ammonium chloride (STAC). We found that STAC can reduce water loss more effectively during fracturing than the cationic surfactant hexadecyl trimethyl ammonium chloride (CTAC). Appropriate amounts of cocoamidopropyl betaine (CAB) increased the viscosity and temperature resistance of the fracturing fluid. It is important to note that as the concentration of sodium salicylate (NaSal) increases, the maximum viscosity of VES fracturing fluid with CAB added is twice that of a fracturing fluid without CAB.

The high concentration of chloride (Cl−) ions in leachate often has negative effects in their harmless treatments, and the common treatments containing the ion exchange method consume excessive antichlors due to their large particle sizes and unfavorable morphologies. Herein, the antichlors of the Bi(III) containing oxides with quantum dots (QDs) or two-dimensional (2D) structures are first explored for the removal and recovery of Cl− ions in concentrated leachate. By using the QDs/2D flakes constructed antichlors of Bi2O3 and the magnetite Bi-Ti composite, the maximum Cl− removal rates of 61.8% and 66.1% are respectively achieved under the optimum conditions. The higher removal efficiency of the magnetite Bi-Ti composite is contributed by its less stable crystal phases of Bi25FeO40/Bi12TiO20, which can proceed more deeply in the removal of Cl− ions compared with that of Bi2O3. The recovered terminal magnetite Bi-Ti precipitate with Bi2O3/BiOCl heterostructure exhibits excellent photocatalytic activity in the degradation of the dechlorinated leachate, where a total organic carbon removal rate of 87.2% is achieved under UV–vis-near-infrared irradiation. Therefore, the selection of Bi(III) containing oxides opens a promising and high-value method for the removal and recovery of Cl− ions in leachate and other waste waters.

In gas–solid flows, particle–particle interaction (typical, particle collision) is highly significant, despite the small particles fractional volume. Widely distributed polydisperse particle population is a typical characteristic during dynamic evolution of particles (e.g., agglomeration and fragmentation) in spite of their initial monodisperse particle distribution. The conventional direct simulation Monte Carlo (DSMC) method for particle collision tracks equally weighted simulation particles, which results in high statistical noise for particle fields if there are insufficient simulation particles in less-populated regions. In this study, a new differentially weighted DSMC (DW-DSMC) method for collisions of particles with different number weight is proposed within the framework of the general Eulerian–Lagrangian models for hydrodynamics. Three schemes (mass, momentum and energy conservation) were developed to restore the numbers of simulation particle while keeping total mass, momentum or energy of the whole system unchanged respectively. A limiting case of high-inertia particle flow was numerically simulated to validate the DW-DSMC method in terms of computational precision and efficiency. The momentum conservation scheme which leads to little fluctuation around the mass and energy of the whole system performed best. Improved resolution in particle fields and dynamic behavior could be attained simultaneously using DW-DSMC, compared with the equally weighted DSMC. Meanwhile, computational cost can be largely reduced in contrast with direct numerical simulation.

The particle capture process of fibrous filter depends on not only filtration velocity, packing density of fibers, particle and fiber diameters, but also fiber arrangement (e.g. parallel model, staggered model, and separation ratio). In this work, the Lattice Boltzmann–Cellular Automata (LB–CA) probabilistic model for particle-laden flows was introduced to simulate the filtration process of multi-layer fiber filters with different fiber arrangement, and then the effects of the fiber arrangement on the capture efficiency, pressure drop, quality factor, and capture contribution were investigated. It was found that the staggered model performs better than the parallel model and its capture efficiency is higher than that of the parallel model. In addition, the capture efficiency and pressure drop both increase with the fiber separation ratio, while the quality factor decreases. With respect to the capture contributions of various rows of fibers in the steady and unsteady filtration processes, the fore fibers (especially the first row in the parallel model and the first two rows in the staggered model) play a more important role than the rear ones, especially when inertial impaction is predominant. Furthermore, the dynamic evolution of particle deposition patterns, pressure drop, capture efficiency, quality factor, and capture contribution due to different capture mechanisms in the particle loading of multi-fiber filters were investigated. The key factors to determine the dendritic structures are the shielding effect in the parallel model and the “river diversion” effect in the staggered model. Both the capture efficiency and pressure drop increases with the particle loading, however the pressure drop increases faster, resulting in the decrease of the quality factor. For the loading process of larger particles in the parallel model the pressure drop from the LB–CA model agree well with the predictions of the empirical model, and the interceptive capture efficiency predicted by the empirical model is also in good agreement with the LB–CA results. However, no model considers the fiber arrangement and different capture mechanisms. The LB–CA simulation provides good understanding in the dynamic filtration processes of multi-layer fibrous fibers, which is useful for filter design and arrangement optimization.

The simulation of turbulent gas-solid flows at the mesoscopic scale is still challenging in fluid mechanics. This paper proposed the Lattice Boltzmann-cellular automata (LB-CA) probabilistic model to simulate gas-solid flows, in which the two-way coupling between the carrier phase and the dispersed phase is considered. In the LB-CA model, the LB subgrid model for high Reynolds number flows is used to describe flow fields at the mesoscopic scale, and the CA probabilistic model utilizing the stochastic process is used to capture transport behavior of discrete solid particles among the same regular lattice nodes as fictitious fluid particles in the LB method. The transport probability of a solid particle to nearest neighboring node directly depends on its actual displacement under other external forces (e.g., drag force, gravity). The two-way coupling is realized by adding external force term for the feedback forcing of particles in the evolution equation of fluid particle density distribution function. The resultant LB-CA model with two-way coupling is then used to simulate gas-particle flows over a backward-facing step. By comparing the present results with experimental measurements and other simulation results from LES (large-eddy simulation)-Lagrangian model, LB-Lagrangian model and two-fluid model, it is found that the LB-CA model is capable of simulating mean and fluctuating velocities of the carrier and dispersed phases and gas-particle covariance with high precision. Generally, the LB-CA method achieves the similar precision with the LES-Lagrangian method, and performs better than some other macroscopic models (such as the two-fluid models).

The deposition of particulate matter on filter fibers (a system of cylinders) in a laminar flow normal to their axes has been simulated by a new Lattice Boltzmann model for two-phase flows. In the model, gas dynamics is solved by the Lattice Boltzmann method, while the transport of solid particle is described by the cellular automation probabilistic approach, where solid particles are constrained to move only on the same regular nodes as the fluid particles and their motion probabilities to neighboring lattices depend on the combined effect of drag forces from fluid, Brownian diffusion, and other external forces. The Lattice Boltzmann two-phase flow model is allowed to quantitatively simulate the filtration process of fibrous assembly, including the steady capture efficiency and pressure drop during the filtration processes of clean fibers, the dynamic evolution of the branch cluster structure, capture efficiency and pressure drop along with particle loading. The detailed information on the particle trajectories and the dendrite structures (fractral dimension and porosity) are obtained. Our results are in good agreement with previous theoretical predictions and experimental observations.