Comparative analysis on gas–solid drag models in MFIX-DEM simulations of bubbling fluidized bed

In this study,the open-source software MFIX-DEM simulations of a bubbling fluidized bed(BFB)are applied to assess nine drag models according to experimental and direct numerical simulation(DNS)results.The influence of superficial gas velocity on gas–solid flow is also examined.The results show that according to the distribution of time-averaged particle axial velocity in y direction,except for Wen–Yu and Tenneti–Garg–Subramaniam(TGS),other drag models are consistent with the experimental and DNS results.For the TGS drag model,the layer-by-layer movement of particles is observed,which indicates the particle velocity is not correctly predicted.The time domain and frequency domain analysis results of pressure drop of each drag model are similar.It is recommended to use the drag model derived from DNS or fine grid computational fluid dynamics–discrete element method(CFD-DEM)data first for CFD-DEM simulations.For the investigated BFB,the superficial gas velocity less than 0.9 m·s^(-1) should be adopted to obtain normal hydrodynamics.

Transcriptomic analysis of biofilm formation by Bacillus cereus under different carbon source conditions

Background:Previous studies found differences in the utilization of different carbon sources during biofilm formation by Bacillus cereus.Illumina HiSeq high-throughput sequencing technology was used to investigate the changes in gene transcript levels in Bacillus cereus biofilm bacteria under different carbon source conditions.Results:Compared with the control group,the number of differentially expressed genes in the glucose,maltose,lactose,and skim milksupplemented groups was 351,1136,133,and 487,respectively.The results showed that the pathways involved in the differentially expressed genes were mainly distributed in glycolysis and pentose phosphate pathway,tricarboxylic acid cycle,amino acid metabolism,and fatty acid metabolism.The gene expression of enzymes related to acetoin synthesis from pyruvate was mostly upregulated in the glucose-supplemented group.The gene expression of enzymes related to pyruvate synthesis of branched-chain amino acids in the maltose-supplemented group was mostly upregulated.In the lactose-supplemented group,the gene expression of acetoin biosynthesis from pyruvate was upregulated.Pyruvate production through glycolysis pathway increased in the skim milk-supplemented group,but the metabolic capacity of the tricarboxylic acid cycle did not change significantly.Conclusion:The content of pyruvate stored by Bacillus cereus biofilm bacteria through glycolysis or pentose phosphate pathway increased,but the carbon flux into the tricarboxylic acid cycle did not increase,which suggested that carbon fluxes in the extracellular polysaccharide synthesis pathway of the biofilm may be increased,resulting in increased biofilm biomass formation.

BMLP:behavior-aware MLP for heterogeneous sequential recommendation

1 Introduction Recommender systems can effectively alleviate the problem of information overload.However,traditional recommendation methods cannot capture users’dynamic interests.Sequential recommendation methods model user sequences to obtain more accurate and dynamic user interests.Recently,deep learning-based sequential recommendation methods have achieved great success.RNN is proposed to capture the sequential information[1,2].Attention-based methods[3]use attention mechanisms to learn relationships between items.GNN-based methods[4−6]transform sequences into graph structures to capture relationships of items.However,they have the following two limitations.

Liquid state dependent solidification of a Co-B eutectic alloy under a high magnetic field

The structure transition inside the Co-81.5at.%B alloy liquid has been studied by an in-situ magnetization measurement.A crossover was observed on the 1/M-T curve during the overheating process,indicating that a liquid-liquid structure transition(LLST)took place in the melt.Based on this information,the effects of LLST on the solidification behavior,microstructure and tribology property were investigated experimentally.The sample solidified with the LLST exhibits significantly different solidification behaviors,i.e.,the nucleation undercooling and the recalescence extent are conspicuously enlarged,and the solidification time is shortened.As a result,the microstructure is effectively refined and homogenized,and the hardness and wear resistance are significantly enhanced.The present work might be helpful for not only theoretically understanding the influence of LLST on the solidification behavior but also providing an alternative approach to tailor the microstructure and properties.

Rh-Catalyzed Formal[3+2]Cyclization for the Synthesis of 5-Aryl-2-(quinolin-2-yl)oxazoles and Its Applications in Metal lons Probes

Main observation and conclusion A facile and efficient strategy for the synthesis of 5-aryl-2-(quinolin-2-yl)oxazoles via rhodium-catalyzed formal[3+2]cyclization of 4-aryl-1-tosyl-1H-1,2,3-triazoles with quinoline-2-carbaldehydes has been described.The protocol employs mild conditions and offers good yields of diverse 2,5-aryloxazole derivatives with a broad reaction scope.It is amenable to gram-scale synthesis and easily transformation.Moreover,this 5-aryl-2-(quinolin-2-yl)oxazole skeleton is indeed a new fluorophore and its applications in metal ions probes are also investigated and showed fluorescent responses to mercury ion.

Transcriptomic analysis of biofilm formation by Bacillus cereus under different carbon source conditions

Background:Previous studies found differences in the utilization of different carbon sources during biofilm formation by Bacillus cereus.Illumina HiSeq high-throughput sequencing technology was used to investigate the changes in gene transcript levels in Bacillus cereus biofilm bacteria under different carbon source conditions.Results:Compared with the control group,the number of differentially expressed genes in the glucose,maltose,lactose,and skim milksupplemented groups was 351,1136,133,and 487,respectively.The results showed that the pathways involved in the differentially expressed genes were mainly distributed in glycolysis and pentose phosphate pathway,tricarboxylic acid cycle,amino acid metabolism,and fatty acid metabolism.The gene expression of enzymes related to acetoin synthesis from pyruvate was mostly upregulated in the glucose-supplemented group.The gene expression of enzymes related to pyruvate synthesis of branched-chain amino acids in the maltose-supplemented group was mostly upregulated.In the lactose-supplemented group,the gene expression of acetoin biosynthesis from pyruvate was upregulated.Pyruvate production through glycolysis pathway increased in the skim milk-supplemented group,but the metabolic capacity of the tricarboxylic acid cycle did not change significantly.Conclusion:The content of pyruvate stored by Bacillus cereus biofilm bacteria through glycolysis or pentose phosphate pathway increased,but the carbon flux into the tricarboxylic acid cycle did not increase,which suggested that carbon fluxes in the extracellular polysaccharide synthesis pathway of the biofilm may be increased,resulting in increased biofilm biomass formation.