Dynamic self-adaptive ANP algorithm and its application to electric field simulation of aluminum reduction cell

Region partition(RP) is the key technique to the finite element parallel computing(FEPC),and its performance has a decisive influence on the entire process of analysis and computation.The performance evaluation index of RP method for the three-dimensional finite element model(FEM) has been given.By taking the electric field of aluminum reduction cell(ARC) as the research object,the performance of two classical RP methods,which are Al-NASRA and NGUYEN partition(ANP) algorithm and the multi-level partition(MLP) method,has been analyzed and compared.The comparison results indicate a sound performance of ANP algorithm,but to large-scale models,the computing time of ANP algorithm increases notably.This is because the ANP algorithm determines only one node based on the minimum weight and just adds the elements connected to the node into the sub-region during each iteration.To obtain the satisfied speed and the precision,an improved dynamic self-adaptive ANP(DSA-ANP) algorithm has been proposed.With consideration of model scale,complexity and sub-RP stage,the improved algorithm adaptively determines the number of nodes and selects those nodes with small enough weight,and then dynamically adds these connected elements.The proposed algorithm has been applied to the finite element analysis(FEA) of the electric field simulation of ARC.Compared with the traditional ANP algorithm,the computational efficiency of the proposed algorithm has been shortened approximately from 260 s to 13 s.This proves the superiority of the improved algorithm on computing time performance.

Drift field improvement and test in a GEM-TPC prototype

With the help of Maxwell, Ansys and Garfield, a simulation of the electric field and the deviation of electron drift in the drift volume of a GEM-TPC prototype has been accomplished under the following conditions： Field Cages with one-side and double-side strips, with and without a guard ring. The advantage and necessity of a Field Cage with mirror strips and a guard ring were foreseen. According to the simulation results, TU-TPC was modified and tested; a larger effective area and better resolution were achieved.

Multi-functional stainless steel composite frames stabilize the sodium metal battery

The sodium(Na)metal battery has the prospect of promising high energy density and sustainable tech-nology for low-cost energy storage.However,the soft texture and high reactivity of Na cause it easy to structure collapse and produce side reactions with organic electrolytes.Inspired by ancient Chinese ar-chitecture,a structural engineering strategy is introduced to conquer the above issues.PVDF film-covered stainless steel mesh(SMPF)embedded in the obverse of Na metal to form a“self-limiting”Na/electrolyte interface and bare stainless steel mesh(SM)with high electronic conductivity embedded in the reverse of Na metal to form a uniformly electronic distributed Na/collector interface.Based on the electric field simulation and in-situ optical tests,the well-designed structure of the SM@Na@SMPF electrode can re-strict the dendrite growth and slow down the bubbles release.The above strategies provide important technical support for the large-scale application of flexible Na metal batteries.

High-Throughput Free Surface Electrospinning Using Solution Reservoirs with Different Depths and Its Preparation Mechanism Study

For obtaining high-throughput production of nanofibers,the preparation mechanism of a self-made spherical section free surface electrospinning(SSFSE)using solution reservoirs with different depths was studied.The effects of the solution res-ervoir depth on the SSFSE process as well as the quality and yield of polyacrylonitrile(PAN)nanofibers were investigated experimentally using high-speed camera,precise electronic balance and scanning electron microscopy.Furthermore,the results were analyzed theoretically by response surface methodology(RSM)and numerical simulation.The values predicted by the established RSM model and the electric field results obtained by Maxwell 3D were all consistent with the experimental data,which showed that the different depths of the solution reservoir had little effect on the quality of PAN nanofibers,but had great effects on the yields of them.The PAN nanofibers prepared have the best quality and the highest yields when the maximum depth of the solution reservoir was 4.29 mm.