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The equilibrium radiation diffusion equation has been widely used in astrophysics, inertial confinement fusion and others. Since the simulation domain consists of many complicated domains and the material properties in each domain are different, the diffusion coefficient usually has a strong discontinuity at the interface. Because the equilibrium radiation diffusion equation is often built on complicated domains as well as interfaces and has a strong nonlinearity, it is challenging to solve by means of finite difference method and so on. By treating T 4 with different linearization methods, three meshfree methods are utilized to approximate the two-dimensional equilibrium radiation diffusion equation with jump coefficient. Firstly, the time term is discretized by the fully implicit scheme. Then, three different linearization methods (direct linearization, Picard-Newton linearization and Richtmyer linearization) are utilized to linearize T 4. Finally, the linearized algebraic equations are solved numerically by a non-symmetric collocation method with a compactly supported radial basis function. Numerical experiments are performed on the three algorithms for different regular and irregular domains with highly curved interfaces. The effectiveness of the proposed algorithms is verified by numerical results. [ABSTRACT FROM AUTHOR]

[Display omitted] • A mechanism of grain thinning and shearing induced recrystallization was proposed for the refinement of centimeter-grade coarse grains of Ti 2 AlNb alloy. • Reduction per compression in multi-directional isothermal forging is more vital than total strain for the refinement of this alloy. • Recrystallization relies on the shear bands and truncation of the thinned grains prepared by prior compressions. • Thinned grains were sheared and truncated due to the bending and bowing of the neighbor grains. Centimeter-grade coarse grains commonly exist in heavy ingots of Ti 2 AlNb-based alloy and severely deteriorate their workability. To investigate the refinement of coarse grains, multi-directional isothermal forging (MDIF) was carried out on samples cut from an ingot weighing about three tons. The results showed that the alloy can be refined by MDIF after 4 passes with 40% reduction per compression at 1200℃, while it cannot be refined even after 10 passes with 30% reduction per compression at 1200℃ or with 40% reduction per compression at 1050℃. The investigation showed that, as an intermetallics with low strain hardening rate, the material is very difficult to be refined by recrystallization if only increasing the total strain. The special refinement mechanism, i.e. , grain thinning and shearing (GTS) induced recrystallization, is proposed. The reduction per compression is crucial to refine the coarse grains of this alloy. Coarse grains should be firstly squashed and thinned by large reduction, and then bent and bowed to form shear bands in the following perpendicular compressions. Coarse grains are truncated by repeated shearing, and the truncation increases interfaces within the coarse grains and contributes to the local misorientation accumulation, which in turn promotes the completion of recrystallization. [ABSTRACT FROM AUTHOR]

As a cost-effective solution for transporting corrosive hydrocarbons, mechanically lined pipe has been used in many offshore and onshore projects. The bonding between the carbon steel carrier and the non-corrosive liner is commonly achieved by mechanical expansion. As typical pipeline damage, the local dent brings deformation to the bimetallic composite, which is expected to undermine the structural integrity. This work investigates the influence of a local dent on the plastic responses and stability of a lined pipe system during bending. Part I presents the results of the experiments and numerical analysis involving a set of small-scale lined tubes. The lined tubes, made of carbon steel Grade GB45 (AISI 1045) and copper Grade T2, are manufactured using a custom hydraulic expansion facility. The products have finished diameters of 50 mm and an overall D / t of 16.5, with 1.0 mm thickness for the liner. A minor transverse dent is introduced to the specimen using a cylindrical indenter. The dented tube is subsequently bent to collapse in a four-point bending facility. It is found that the local dent tends to induce early collapse of both the outer tube and the liner, resulting in a noteworthy reduction of the bending capacity of the composite. Initially, the local dent grows stably instead of collapsing right away. With increasing bending, the liner develops a major buckle and several satellite dimples around it. Subsequently, the manufacture, indentation, and the succeeding bending to collapse are simulated using a custom numerical framework, and the experimental results are reproduced reasonably well. Part II will use the validated numerical model to conduct an extensive parametric study of the important variables of the problem for full-scale lined pipes. [ABSTRACT FROM AUTHOR]

[Display omitted] • A recyclable PCNs@PCP-La was firstly fabricated for phosphate removal. • The phosphate uptake capacity was up to 121.2 mg P g−1. • PCNs@PCP-La showed rapid adsorption, high capacity, attractive selectivity and high pH adaptability. • PCNs@PCP-La presented a superior reusability for phosphate removal. • Multiple techniques were used to demonstrate the adsorption mechanisms. Phosphate removal has been the top priority in eutrophic wastewater treatment. Herein we reported a fast, efficient and selective adsorbent, PCNs@PCP-La, for phosphate removal from an aqueous medium. The adsorbent was fabricated via two steps: (1) synthesis of PCNs@PCP composite through in situ polymerization of hexachlorocyclotriphosphazene and polyethyleneimine on the porous carbon nanosheets; and (2) lanthanum ion (La3+) modification of PCNs@PCP via an impregnation process to create PCNs@PCP-La hybrid. Multiple characterizations showed that the atomically dispersed La3+ ions could be facilely chelated with nitrogen-rich cyclomatrix polyphosphazene framework, significantly improving the application efficiency of La3+ ions as active adsorption sites. Comparative tests confirmed that PCNs@PCP-La had a high phosphate uptake capacity of up to 121.2 mg P g−1 (pH = 4.0) at 298 K and performed well even in a wide pH range (3.0–9.0). Also, PCNs@PCP-La showed a particularly short saturated adsorption time (5 min), indicating a fast adsorption kinetic process. Meanwhile, PCNs@PCP-La presented a superior adsorption selectivity for phosphate under interference with coexisting anions/cation and humic acid, and owned an attractive reusability (after 5th cycles, 85% capacity retention). The plausible adsorption mechanism can be ascribed to electrostatic attraction, inner-sphere complexation, and the formation of LaPO 4 ·0.5H 2 O precipitates between adsorbent and adsorbate. [ABSTRACT FROM AUTHOR]

• N treatment approach and sampling time affected fine root biomass and morphology. • Canopy N addition increased fine root biomass. • Fine root biomass and morphology were mainly affected in the growing season. • Fine root biomass was most affected by NH 4 -N and NO 3 -N in growing season. Global nitrogen (N) deposition patterns have profoundly affected the production and morphological structure of fine roots, which in turn changed the distribution of carbon in forests. However, traditional experiments of N addition in forests have ignored the ecological processes in the canopy, such as nitrogen retention, and the effects of these on N deposition and fine root functional traits remain unclear. In this study, we quantified the effects of the canopy (CAN) and understory N addition (UAN) on the biomass and morphology of fine roots in a temperate deciduous forest. Based on the three-way ANOVA, we found that the N treatment approach (CAN vs. UAN; p < 0.05) and sampling time (July, October, and January; p < 0.001) significantly affected the fine root biomass, specific root length, specific root surface area, and root tissue density and diameter. Through the summation of fine root biomass, it was found that CAN treatment increased fine root biomass, while UAN treatment decreased fine root biomass, and canopy N addition at 50 kg ha-1yr−1 (CAN50) significantly increased fine root biomass compared with understory N addition at 50 kg ha-1yr−1 (UAN50) in July and October (p < 0.05). Redundancy analysis (RDA) showed that fine root biomass was most affected by NH 4 -N and NO 3 -N in July. There was no consistent response of fine root morphology to the N application method and N addition rate; it was mainly affected by season (p < 0.001). Different results were obtained using different N treatment approaches. The effects of UAN on forest fine root biomass were likely overestimated compared to the effects of CAN. Our experimental results will provide a scientific basis for a more accurate prediction of the impacts of future global N deposition on fine roots in forest ecosystems. [ABSTRACT FROM AUTHOR]