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Experimental study of two saturated natural soils and their saturated remoulded soils under three consolidated undrained stress paths

Mingjing JIANG, Haijun HU, Jianbing PENG, Serge LEROUEIL

《结构与土木工程前沿（英文）》 2011年 第5卷 第2期   页码 225-238 doi: 10.1007/s11709-011-0108-8

摘要： In this paper, an experimental investigation is conducted to study the mechanical behavior of saturated natural loess, saturated natural filling in ground fissure and their corresponding saturated remoulded soils under three consolidated undrained triaxial stress tests, namely, conventional triaxial compression test (CTC), triaxial compression test (TC) and reduced triaxial compression test (RTC). The test results show that stress-strain relation, i.e. strain-softening or strain-hardening, is remarkably influenced by the structure, void ratio, stress path and confining pressure. Natural structure, high void ratio, TC stress path, RTC stress path and low confining pressures are favorable factors leading to strain-softening. Excess pore pressure during shearing is significantly affected by stress path. The tested soils are different from loose sand on character of strain-softening and are different from common clay on excess pore water pressure behavior. The critical states in ′– space in CTC, TC and RTC tests almost lie on one line, which indicates that the critical state is independent of the above stress paths. As for remoulded loess or remoulded filling, the critical state line (CSL) and isotropic consolidation line (ICL) in -log ′ space are almost straight, while for natural loess or natural filling, in -log ′ space there is a turning point on the CSL, which is similar to the ICL.

关键词： stress paths     static liquefaction     natural soil     remoulded soil     loess     structure     total strength indices     excess pore pressure    

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Upper bound solution to seismic active earth pressure of submerged backfill subjected to partial drainage

《结构与土木工程前沿（英文）》 2021年 第15卷 第6期   页码 1480-1493 doi: 10.1007/s11709-021-0776-y

摘要： In waterfront geotechnical engineering, seismic and drainage conditions must be considered in the design of retaining structures. This paper proposes a general analytical method to evaluate the seismic active earth pressure on a retaining wall with backfill subjected to partial steady seepage flow under seismic conditions. The method comprises the following steps: i) determination of the total head, ii) upper bound solution of seismic active earth thrust, and iii) deduction for the earth pressure distribution. The determination of total head h(x,z) relies on the Fourier series expansions, and the expressions of the seismic active earth thrust and pressure are derived by using the upper bound theorem. Parametric studies reveal that insufficient drainage and earthquakes are crucial factors that cause unfavorable earth pressure. The numerical results confirm the validity of the total head distribution. Comparisons indicate that the proposed method is consistent with other relevant existing methods in terms of predicting seismic active earth pressure. The method can be applied to the seismic design of waterfront retaining walls.

关键词： seismic active earth pressure     partial seepage flow     pore pressure     anisotropy     upper bound theorem    

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Solutions for a completely saturated porous elastic solid with impeded boundaries

CHEN Yunmin, LING Daosheng, ZHU Bin, CHENG Zehai

《结构与土木工程前沿（英文）》 2007年 第1卷 第3期   页码 322-328 doi: 10.1007/s11709-007-0042-y

摘要： Analytical solutions are presented for the consolidation of a semi-infinite stratum and a finite soil layer with an impeding layer located on the surface subjected to a vertical point loading. The Laplace transform and the Hankel transform are used with respect to time and the radial coordinate, respectively. Solutions of other distributed loadings, including the circular loading, can be easily obtained by integrating those of the point loading. The consolidation degree, excess pore water pressure, vertical total stress, and the shear stress of the consolidating layer are analyzed in this study. The consolidation rate decreases with the increase in the thickness of the impeding layer. Stresses of the consolidating layer vary during the consolidation due to the coupling of the excess pore water dissipation and the soil skeleton deformation. Further, the Mandel-Cryer effect is also analyzed in this study.

关键词： coupling     vertical     pressure     excess     distributed    

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Analyzing the characterization of pore structures and permeability of diesel contaminated clays under

《结构与土木工程前沿（英文）》   页码 1264-1280 doi: 10.1007/s11709-023-0921-x

摘要： In this study, mercury intrusion porosimetry (MIP) and X-ray micro-computed tomography (XRμCT) were used to characterize the pore structures and investigate the permeability characteristics of clay after aging and contamination with diesel. The results of the MIP tests showed that aging leads to reductions in porosity and average diameter, as well as an increase in tortuosity. The XRμCT analysis yielded consistent results; it showed that aging renders pores more spherical and isotropic and pore surfaces smoother. This weakens the pore connectivity. Micromorphological analysis revealed that aging led to the rearrangement of soil particles, tighter interparticle overlapping, and a reduction in pore space. The combination of MIP and XRμCT provided a comprehensive and reliable characterization of the soil pore structure. An increased diesel content increased the porosity and average diameter and reduced the tortuosity of the pores. Mechanistic analysis showed that aging weakens interparticle cohesion; this causes large agglomerates to break down into smaller agglomerates, resulting in a tighter arrangement and a subsequent reduction in porosity. An increase in diesel content increases the number of large agglomerates and pore spaces between agglomerates, resulting in increased porosity. Both aging and diesel content can weaken the permeation characteristics of soil.

关键词： MIP     XRμCT     aging     diesel content     pore structure     permeability characteristics    

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Projections of heat-related excess mortality in China due to climate change, population and aging

《环境科学与工程前沿（英文）》 2023年 第17卷 第11期 doi: 10.1007/s11783-023-1732-y

摘要：

● Four scenarios were used to project heat-related excess mortality in China.

关键词： Heat-related excess mortality     LMDI     Aging     YLL     VSLY    

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Catalyst particle shapes and pore structure engineering for hydrodesulfurization and hydrodenitrogenation

《化学科学与工程前沿（英文）》 2022年 第16卷 第6期   页码 897-908 doi: 10.1007/s11705-021-2127-x

摘要： Catalyst particle shapes and pore structure engineering are crucial for alleviating internal diffusion limitations in the hydrodesulfurization (HDS)/hydrodenitrogenation (HDN) of gas oil. The effects of catalyst particle shapes (sphere, cylinder, trilobe, and tetralobe) and pore structures (pore diameter and porosity) on HDS/HDN performance at the particle scale are investigated via mathematical modeling. The relationship between particle shape and effectiveness factor is first established, and the specific surface areas of different catalyst particles show a positive correlation with the average HDS/HDN reaction rates. The catalyst particle shapes primarily alter the average HDS/HDN reaction rate to adjust the HDS/HDN effectiveness factor. An optimal average HDS/HDN reaction rate exists as the catalyst pore diameter and porosity increase, and this optimum value indicates a tradeoff between diffusion and reaction. In contrast to catalyst particle shapes, the catalyst pore diameter and the porosity of catalyst particles primarily alter the surface HDS/HDN reaction rate to adjust the HDS/HDN effectiveness factor. This study provides insights into the engineering of catalyst particle shapes and pore structures for improving HDS/HDN catalyst particle efficiency.

关键词： hydrodesulfurization     hydrodenitrogenation     particle shape     pore structure    

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Uncoupled state space solution to layered poroelastic medium with anisotropic permeability and compressible pore

Zhiyong AI, Wenze ZENG, Yichong CHENG, Chao WU

《结构与土木工程前沿（英文）》 2011年 第5卷 第2期   页码 171-179 doi: 10.1007/s11709-011-0103-0

摘要： This paper presents an uncoupled state space solution to three-dimensional consolidation of layered poroelastic medium with anisotropic permeability and compressible pore fluid. Starting from the basic equations of poroelastic medium, and introducing intermediate variables, the state space equation usually comprising eight coupled state vectors is uncoupled into two sets of equations of six and two state vectors in the Laplace-Fourier transform domain. Combined with the continuity conditions between adjacent layers and boundary conditions, the uncoupled state space solution of a layered poroelastic medium is obtained by using the transfer matrix method. Numerical results show that the anisotropy of permeability and the compressibility of pore fluid have remarkable influence on the consolidation behavior of poroelastic medium.

关键词： uncoupled state space solution     layered poroelastic medium     three-dimensional consolidation     anisotropic permeability     compressible pore fluid    

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Influence of pore structure on biologically activated carbon performance and biofilm microbial characteristics

《环境科学与工程前沿（英文）》 2021年 第15卷 第6期 doi: 10.1007/s11783-021-1419-1

摘要：

• Pore structure affects biologically activated carbon performance.

关键词： Granular activated carbon     Biologically activated carbon filter     Bacterial community structure     Pore structure    

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Numerical simulation of bituminous coal combustion in a full-scale tiny-oil ignition burner: influence of excess

Zhengqi LI, Chunlong LIU, Xiang ZHANG, Lingyan ZENG, Zhichao CHEN

《能源前沿（英文）》 2012年 第6卷 第3期   页码 296-303 doi: 10.1007/s11708-012-0191-0

摘要： The progression of ignition was numerically simulated with the aim of realizing a full-scale tiny-oil ignition burner that is identical to the burner used in an 800 MWe utility boiler. The numerical simulations were conducted for four excess air ratios, 0.56, 0.75, 0.98 and 1.14 (corresponding to primary air velocities of 17, 23, 30 and 35 m/s, respectively), which were chosen because they had been used previously in practical experiments. The numerical simulations agreed well with the experimental results, which demonstrate the suitability of the model used in the calculations. The gas temperatures were high along the center line of the burner for the four excess air ratios. The flame spread to the burner wall and the high-temperature region was enlarged in the radial direction along the primary air flow direction. The O concentrations for the four excess air ratios were 0.5%, 1.1%, 0.9% and 3.0% at the exit of the second combustion chamber. The CO peak concentration was very high with values of 7.9%, 9.9%, 11.3% and 10.6% for the four excess air ratios at the exit of the second combustion chamber.

关键词： numerical simulation     tiny-oil ignition burner     pulverized coal     temperature field    

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Comparison between inhibitor and uncoupler for minimizing excess sludge production of an activated sludge

CHEN Guowei, XI Pengge, XU Deqian, YU Hanqing

《环境科学与工程前沿（英文）》 2007年 第1卷 第1期   页码 63-66 doi: 10.1007/s11783-007-0012-6

摘要： In order to study the minimization of excess sludge production, the reduction in the excess sludge production in the presence of an inhibitor and uncoupler was studied in this work. The experimental results show that such an addition could effectively reduce the production of excess sludge. With the energy uncoupling model established in this work, energy uncoupling coefficient () was used to evaluate the reduction in excess sludge production. The energy uncoupling coefficients in the presence of dinitrophenol (dNP), Zn, and Cu was 0.75, 0.46, and 0.18, respectively. The analysis demonstrated that energy spilling occurred in the presence of dNP, and that dNP was an effective uncoupler for reducing the production of excess activated sludge without affecting the microbial respiration activity.

关键词： uncoupling coefficient     Cu     minimization     presence     uncoupling    

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Effect of catalyst layer mesoscopic pore-morphology on cold start process of PEM fuel cells

Ahmed Mohmed DAFALLA, Fangming JIANG

《能源前沿（英文）》 2021年 第15卷 第2期   页码 460-472 doi: 10.1007/s11708-021-0733-4

摘要： Water transport is of paramount importance to the cold start of proton exchange membrane fuel cells (PEMFCs). Analysis of water transport in cathode catalyst layer (CCL) during cold start reveals the distinct characteristics from the normal temperature operation. This work studies the effect of CCL mesoscopic pore-morphology on PEMFC cold start. The CCL mesoscale morphology is characterized by two tortuosity factors of the ionomer network and pore structure, respectively. The simulation results demonstrate that the mesoscale morphology of CCL has a significant influence on the performance of PEMFC cold start. It was found that cold-starting of a cell with a CCL of less tortuous mesoscale morphology can succeed, whereas starting up a cell with a CCL of more tortuous mesoscale morphology may fail. The CCL of less tortuous pore structure reduces the water back diffusion resistance from the CCL to proton exchange membrane (PEM), thus enhancing the water storage in PEM, while reducing the tortuosity in ionomer network of CCL is found to enhance the water transport in and the water removal from CCL. For the sake of better cold start performance, novel preparation methods, which can create catalyst layers of larger size primary pores and less tortuous pore structure and ionomer network, are desirable.

关键词： cold start     energy conversion     fuel cells     mesoscale morphology     tortuosity     water management    

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Mechanism on minimization of excess sludge in oxic-settling-anaerobic (OSA) process

WANG Jianfang, ZHAO Qingliang, JIN Wenbiao, LIN Jikan

《环境科学与工程前沿（英文）》 2008年 第2卷 第1期   页码 36-43 doi: 10.1007/s11783-008-0001-4

摘要： The oxic-settling-anaerobic (OSA) process is a promising wastewater treatment technique for efficiently reducing sludge production and improving the stability of process operation. In this paper, the possible factors of sludge reduction such as sludge decay, uncoupled metabolism, and anaerobic oxidation with low sludge production were discussed in the OSA process. It has been confirmed that sludge decay is the decisive cause in the OSA process, accounting for 66.7% of sludge production reduction. Sludge decay includes hydrolysis and acidogenesis of dead microorganisms and particle organic carbon adsorbed in sludge floc and endogenous metabolism. By batch experiments, it has been proven that there is energetic uncoupling in the OSA system since microorganisms were exposed to alternative anaerobic and aerobic environment. It accounts for about 7.5% of sludge production reduction. Soluble chemical oxygen demand (SCOD) released from the anaerobic sludge tank in the OSA process was used as the substrate for cryptic growth. The substrate was used for anoxic denitrifying, anaerobic phosphorus release, sulfate reduction, and methane production. These anaerobic reactions in the sludge anaerobic tank have lower sludge production than in the aerobic oxidation when equivalent SCOD is consumed, which may lead to approximately 23% of sludge reduction in the OSA process. It has been concluded that multiple causes resulted in the minimization of excess sludge in the OSA system. The microbial community structure and diversity of sludge samples from the CAS (conventional activated sludge) and OSA systems were investigated by 16 SrDNA PCR-DG-DGGE (polymerase chain reaction-double gradient-denaturing gradient gel electrophoresis). DGGE profile and cluster analysis showed more abundant species in the OSA system contrasting to microbial communities in the CAS system.
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Collaborative control of fine particles and ozone required in China for health benefit

《环境科学与工程前沿（英文）》 2023年 第17卷 第8期 doi: 10.1007/s11783-023-1692-2

摘要：

● Increased DAAO offsets 3/4 of the decrease of DAAP in 2013–2020.

关键词： Excess deaths     Long-term exposure     Fine particle     Ozone    

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polybenzoxazine-based carbon microspheres with nitrogen functionalities: Effects of mixed solvents on pore

Uthen Thubsuang, Suphawadee Chotirut, Apisit Thongnok, Archw Promraksa, Mudtorlep Nisoa, Nicharat Manmuanpom, Sujitra Wongkasemjit, Thanyalak Chaisuwan

《化学科学与工程前沿（英文）》 2020年 第14卷 第6期   页码 1072-1086 doi: 10.1007/s11705-019-1899-8

摘要： In this study, polybenzoxazine (PBZ)-based carbon microspheres were prepared via a facile method using a mixture of formaldehyde (F) and dimethylformamide (DMF) as the solvent. The PBZ microspheres were successfully obtained at the F/DMF weight ratios of 0.4 and 0.6. These microspheres exhibited high nitrogen contents after carbonization. The microstructures of all the samples showed an amorphous phase and a partial graphitic phase. The porous carbon with the F/DMF ratio of 0.4 showed significantly higher specific capacitance (275.1 F g ) than the reference carbon (198.9 F g ) at 0.05 A g . This can be attributed to the synergistic electrical double-layer capacitor and pseudo-capacitor behaviors of the porous carbon with the F/DMF ratio of 0.4. The presence of nitrogen/oxygen functionalities induced pseudo-capacitance in the microspheres, and hence increased their total specific capacitance. After activation with CO , the specific surface area of the carbon microspheres with the F/DMF ratio of 0.4 increased from 349 to 859 m g and the specific capacitance increased to 424.7 F g . This value is approximately two times higher than that of the reference carbon. The results indicated that the F/DMF ratio of 0.4 was suitable for preparing carbon microspheres with good supercapacitive performance. The nitrogen/oxygen functionalities and high specific surface area of the microspheres were responsible for their high capacitance.

关键词： PBZ     carbon     porous materials     microsphere     supercapacitor    

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Applications of atomic force microscopy in immunology

Jiping Li, Yuying Liu, Yidong Yuan, Bo Huang

《医学前沿（英文）》 2021年 第15卷 第1期   页码 43-52 doi: 10.1007/s11684-020-0769-6

摘要： Cellular mechanics, a major regulating factor of cellular architecture and biological functions, responds to intrinsic stresses and extrinsic forces exerted by other cells and the extracellular matrix in the microenvironment. Cellular mechanics also acts as a fundamental mediator in complicated immune responses, such as cell migration, immune cell activation, and pathogen clearance. The principle of atomic force microscopy (AFM) and its three running modes are introduced for the mechanical characterization of living cells. The peak force tapping mode provides the most delicate and desirable virtues to collect high-resolution images of morphology and force curves. For a concrete description of AFM capabilities, three AFM applications are discussed. These applications include the dynamic progress of a neutrophil-extracellular-trap release by neutrophils, the immunological functions of macrophages, and the membrane pore formation mediated by perforin, streptolysin O, gasdermin D, or membrane attack complex.

关键词： cellular mechanics     atomic force microscopy     neutrophil extracellular trap     macrophage phagocytosis     pore formation    

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标题 作者 时间 类型 操作

Experimental study of two saturated natural soils and their saturated remoulded soils under three consolidated undrained stress paths

Mingjing JIANG, Haijun HU, Jianbing PENG, Serge LEROUEIL

期刊论文

Upper bound solution to seismic active earth pressure of submerged backfill subjected to partial drainage

期刊论文

Solutions for a completely saturated porous elastic solid with impeded boundaries

CHEN Yunmin, LING Daosheng, ZHU Bin, CHENG Zehai

期刊论文

Analyzing the characterization of pore structures and permeability of diesel contaminated clays under

期刊论文

Projections of heat-related excess mortality in China due to climate change, population and aging

期刊论文

Catalyst particle shapes and pore structure engineering for hydrodesulfurization and hydrodenitrogenation

期刊论文

Uncoupled state space solution to layered poroelastic medium with anisotropic permeability and compressible pore

Zhiyong AI, Wenze ZENG, Yichong CHENG, Chao WU

期刊论文

Influence of pore structure on biologically activated carbon performance and biofilm microbial characteristics

期刊论文

Numerical simulation of bituminous coal combustion in a full-scale tiny-oil ignition burner: influence of excess

Zhengqi LI, Chunlong LIU, Xiang ZHANG, Lingyan ZENG, Zhichao CHEN

期刊论文

Comparison between inhibitor and uncoupler for minimizing excess sludge production of an activated sludge

CHEN Guowei, XI Pengge, XU Deqian, YU Hanqing

期刊论文

Effect of catalyst layer mesoscopic pore-morphology on cold start process of PEM fuel cells

Ahmed Mohmed DAFALLA, Fangming JIANG

期刊论文

Mechanism on minimization of excess sludge in oxic-settling-anaerobic (OSA) process

WANG Jianfang, ZHAO Qingliang, JIN Wenbiao, LIN Jikan

期刊论文

Collaborative control of fine particles and ozone required in China for health benefit

期刊论文

polybenzoxazine-based carbon microspheres with nitrogen functionalities: Effects of mixed solvents on pore

Uthen Thubsuang, Suphawadee Chotirut, Apisit Thongnok, Archw Promraksa, Mudtorlep Nisoa, Nicharat Manmuanpom, Sujitra Wongkasemjit, Thanyalak Chaisuwan

期刊论文

Applications of atomic force microscopy in immunology

Jiping Li, Yuying Liu, Yidong Yuan, Bo Huang

期刊论文