A new numerical strategy to model nonlinear damage behavior of RC beam-column member based on level of material and superconvergent computation is presented in this paper. A fiber damage analysis model (FDAM) for RC b...A new numerical strategy to model nonlinear damage behavior of RC beam-column member based on level of material and superconvergent computation is presented in this paper. A fiber damage analysis model (FDAM) for RC beam-column member is established by analyzing section of fiber beam column element with the uniaxial damage constitutive relations of con-crete. The damage index of RC member through statistical analysis of concrete fibers damage is defined in the extreme section of beam elements, which can describe the nonlinear damage behavior of RC beam-column member under any loadings. The newly proposed element energy projection (EEP) method is applied to the inelastic analysis of FDAM. EEP superconvergent formulas for section forces and deformations of beam-column are established, and general algorithm and numerical strategy adopting EEP super-convergent computation for section deformation increment are proposed in the classical Newton-Raphson process. Both analysis and numerical test show that the EEP method can effectively find out the nonlinear feature of the distribution, and accurately obtain the damage distribution of RC beamcolumn. The proposed numerical scheme in this paper proves to be effective and convenient in its use and can be easily integrated into the present inelastic FEM programs of structure analysis.展开更多
The study aims to identify the potential acute effects of suspended aluminum nitride（Al N）nanoparticles（NPs） on soluble microbial products（SMP） of activated sludge.Cultured activated sludge loaded with 1,10,50,1...The study aims to identify the potential acute effects of suspended aluminum nitride（Al N）nanoparticles（NPs） on soluble microbial products（SMP） of activated sludge.Cultured activated sludge loaded with 1,10,50,100,150 and 200 mg/L of Al N NPs were carried out in this study.As results showed,Al N NPs had a highly inverse proportionality to bacterial dehydrogenase and OUR,indicating its direct toxicity to the activated sludge viability.The toxicity of Al N NPs was mainly due to the nano-scale of Al N NPs.In SMP,Al N NPs led to the decrease of polysaccharide and humic compounds,but had slight effects on protein.The decrease of tryptophan-like substances in SMP indicated the inhibition of Al N NPs on the bacterial metabolism.Additionally,Al N NPs reduced obviously the molecular weight of SMP,which might be due to the nano-scale of Al N.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 50938001, 51008048)
文摘A new numerical strategy to model nonlinear damage behavior of RC beam-column member based on level of material and superconvergent computation is presented in this paper. A fiber damage analysis model (FDAM) for RC beam-column member is established by analyzing section of fiber beam column element with the uniaxial damage constitutive relations of con-crete. The damage index of RC member through statistical analysis of concrete fibers damage is defined in the extreme section of beam elements, which can describe the nonlinear damage behavior of RC beam-column member under any loadings. The newly proposed element energy projection (EEP) method is applied to the inelastic analysis of FDAM. EEP superconvergent formulas for section forces and deformations of beam-column are established, and general algorithm and numerical strategy adopting EEP super-convergent computation for section deformation increment are proposed in the classical Newton-Raphson process. Both analysis and numerical test show that the EEP method can effectively find out the nonlinear feature of the distribution, and accurately obtain the damage distribution of RC beamcolumn. The proposed numerical scheme in this paper proves to be effective and convenient in its use and can be easily integrated into the present inelastic FEM programs of structure analysis.
基金supported by the National Natural Science Foundation of China(No.51378368)the Foundation of State Key Laboratory of Pollution Control and Resource Reuse(Tongji University),China(No.PCRRT16003)Shenzhen Science and Technology Research Fund(No.CXZZ20150330151321966)
文摘The study aims to identify the potential acute effects of suspended aluminum nitride（Al N）nanoparticles（NPs） on soluble microbial products（SMP） of activated sludge.Cultured activated sludge loaded with 1,10,50,100,150 and 200 mg/L of Al N NPs were carried out in this study.As results showed,Al N NPs had a highly inverse proportionality to bacterial dehydrogenase and OUR,indicating its direct toxicity to the activated sludge viability.The toxicity of Al N NPs was mainly due to the nano-scale of Al N NPs.In SMP,Al N NPs led to the decrease of polysaccharide and humic compounds,but had slight effects on protein.The decrease of tryptophan-like substances in SMP indicated the inhibition of Al N NPs on the bacterial metabolism.Additionally,Al N NPs reduced obviously the molecular weight of SMP,which might be due to the nano-scale of Al N.
