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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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Chemically reactive solute transfer in a boundary layer slip flow along a stretching cylinder

Swati Mukhopadhyay

《化学科学与工程前沿（英文）》 2011年 第5卷 第3期   页码 385-391 doi: 10.1007/s11705-011-1101-4

摘要： This paper presents the distribution of a solute undergoing a first order chemical reaction in an axisymmetric laminar boundary layer flow along a stretching cylinder. Velocity slip condition at the boundary is used instead of no-slip condition. Similarity transformations are used to convert the partial differential equations corresponding to momentum and concentration into highly nonlinear ordinary differential equations. Numerical solutions of these equations are obtained by the shooting method. The velocity decreases with increasing slip parameter. The skin friction as well as the mass transfer rate at the surface is larger for a cylinder than for a flat plate.

关键词： boundary layer     stretching cylinder     partial slip     mass transfer     similarity solution    

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环境同位素示踪方法研究新安江右坝肩绕坝渗流

陈建生,刘建刚,董海洲,陈亮

《中国工程科学》 2004年 第6卷 第1期   页码 57-63

摘要：

通过分析新安江右坝区环境水中的同位素2H，18O，3H以及温度与电导分布，研究新安江右坝存在的绕坝渗流场。环境同位素数据证实了右坝肩基岩中存在着绕坝渗漏，排水廊道中的排水既有边坡降雨入渗，又有库水的绕坝肩补给，排水廊道扇形孔中的渗水完全来自于绕坝肩的库水渗漏。3E1-1扬压力升高的原因是由于F0断层渗漏造成的结果，但6坝段和7坝段下部的F1断层基本上不存在渗漏,灌浆廊道G7-4排水孔中渗水中的3H高达19.54TU，证实该渗漏水来自坝后区的降雨补给。右坝肩观测孔R3和R6等孔中发现绕坝库水成分，环境同位素数据同时证实了人工示踪方法得到的结论。

关键词： 环境同位素     绕坝渗流     大气降水     水库    

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Foundations bearing capacity subjected to seepage by the kinematic approach of the limit analysis

Mehdi VEISKARAMI, Ghasem HABIBAGAHI

《结构与土木工程前沿（英文）》 2013年 第7卷 第4期   页码 446-455 doi: 10.1007/s11709-013-0227-5

摘要： An estimate of the ultimate load on foundations on soil layers subject to groundwater flow has been presented. The kinematic approach of the limit analysis was employed to find the upper-bound limit of the bearing capacity. Both smooth and rough base strip foundations were considered associated with different collapse patterns. Presence of the groundwater flow leads to a non-symmetric collapse pattern, i.e., a weak side and a strong side in two-sided collapse patterns, depending on the direction of the flow. It was found that the bearing capacity has a decreasing trend with increase in the groundwater flow gradient and hence, a reduction factor has been introduced to the third term in the bearing capacity equation as a function of the flow gradient.

关键词： foundation     bearing capacity     limit analysis     numerical computation     plasticity     seepage    

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Estimation of photolysis half-lives of dyes in a continuous-flow system with the aid of quantitative

Davoud BEIKNEJAD,Mohammad Javad CHAICHI

《环境科学与工程前沿（英文）》 2014年 第8卷 第5期   页码 683-692 doi: 10.1007/s11783-014-0680-y

摘要： In this paper the photolysis half-lives of the model dyes in water solutions and under ultraviolet (UV) radiation were determined by using a continuous-flow spectrophotometric method. A quantitative structure-property relationship (QSPR) study was carried out using 21 descriptors based on different chemometric tools including stepwise multiple linear regression (MLR) and partial least squares (PLS) for the prediction of the photolysis half-life ( ) of dyes. For the selection of test set compounds, a K-means clustering technique was used to classify the entire data set, so that all clusters were properly represented in both training and test sets. The QSPR results obtained with these models show that in MLR-derived model, photolysis half-lives of dyes depended strongly on energy of the highest occupied molecular orbital ( ), largest electron density of an atom in the molecule ( ) and lipophilicity (log ). While in the model derived from PLS, besides aforementioned and descriptors, the molecular surface area ( ), molecular weight ( ), electronegativity ( ), energy of the second highest occupied molecular orbital ( ) and dipole moment ( ) had dominant effects on logt values of dyes. These were applicable for all classes of studied dyes (including monoazo, disazo, oxazine, sulfonephthaleins and derivatives of fluorescein). The results were also assessed for their consistency with findings from other similar studies.

关键词： dye     photolysis half-life     quantitative structure-property relationship     continuous-flow     stepwise multiple linear regression     partial least squares    

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Surficial stability analysis of soil slope under seepage based on a novel failure mode

《结构与土木工程前沿（英文）》 2021年 第15卷 第3期   页码 712-726 doi: 10.1007/s11709-021-0729-5

摘要： Normally, the edge effects of surficial landslides are not considered in the infinite slope method for surficial stability analysis of soil slopes. In this study, the limit stress state and discrimination equation of an infinite slope under saturated seepage flow were analyzed based on the Mohr-Coulomb strength criterion. Therefore, a novel failure mode involving three sliding zones (upper tension zone, middle shear sliding zone, and lower compression zone) was proposed. Accordingly, based on the limit equilibrium analysis, a semi-analytical framework considering the edge effect for the surficial stability of a soil slope under downslope seepage was established. Subsequently, the new failure mode was verified via a numerical finite element analysis based on the reduced strength theory with ABAQUS and some simplified methods using SLIDE software. The results obtained by the new failure mode agree well with those obtained by the numerical analysis and traditional simplified methods, and can be efficiently used to assess the surficial stability of soil slopes under rainwater seepage. Finally, an evaluation of the infinite slope method was performed using the semi-analytical method proposed in this study. The results show that the infinite slope tends to be conservative because the edge effect is neglected, particularly when the ratio of surficial slope length to depth is relatively small.

关键词： soil slope     seepage     surficial failure mode     stress state     edge effects    

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Quantification of seepage in a multi-layered disconnected river-aquifer system

Jiang LI, Haizhu HU, Xiaomin MAO, Yi LIU

《农业科学与工程前沿（英文）》 2017年 第4卷 第2期   页码 237-245 doi: 10.15302/J-FASE-2017135

摘要： Quantification of seepage in disconnected river-aquifer systems is significant for local water management and groundwater pollution control, especially in areas with water shortage or contamination. The vadose zone under riverbeds usually exhibits a multi-layered structure, particularly when paved with low permeability liners. To evaluate the impact of engineering solutions to seepage under such conditions, we proposed an approach by combining GIS and the minimum flux in saturation layer (MFSL) method. MFSL can calculate the stable seepage rate by assessing the dominant low permeability layers (including but not limited to the liners) in multi-layered disconnected river-aquifer systems. We used MFSL to calculate local seepage rate, and used GIS to extend the results to a regional scale. The reliability of MFSL is discussed by comparing the results with the double ring infiltration test, the numerical simulation by HYDRUS, and the methods of stream package in MODFLOW, including its improved form. A case study was conducted in the Yongding River with river-aquifer seepage calculated under various conditions, including different river water levels (i.e., under the designated water level, drought stage level, flood stage level and flood inundation level) and with/without low permeability liners (i.e., ecological membranes or geomembrane). Results showed that low permeability liners could greatly reduce the seepage rate. However, if an unlined inundation area exists, the seepage rate may increase greatly. The results indicated that the proposed method was reliable and convenient for calculating long-term, large area seepage in disconnected river-aquifer systems especially those paved with liners.

关键词： infiltration     low permeability liner     multi-layered porous media     river-aquifer seepage    

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Seepage analysis of Upper Gotvand Dam concerning gypsum karstification (2D and 3D approaches)

Jamshid SADREKARIMI, Majid KIYANI, Behnam FAKHRI, Mohammad Javad VAHDATIRAD, Amin BARARI

《结构与土木工程前沿（英文）》 2011年 第5卷 第1期   页码 71-78 doi: 10.1007/s11709-010-0083-5

摘要： Upper Gotvand Dam is constructed on the Karun River at the south west of Iran. In this paper, 2D and 3D models of the dam together with the foundation and abutments were established, and several seepage analyses were carried out. Then, the gypsum veins that are scattered throughout the foundation ground were included in the models, and the seepage pattern, considering the dissolution law of gypsum, was analyzed. It was disclosed that the discharge fluxes obtained from 2D and 3D analyses are not similar, and the discharge flux in 3D model is about four times that of the 2D model. Also, the 3D model locates the phreatic surface somewhat higher than the 2D model. This means that the 2D model estimates lower pore water pressure pattern in comparison with the 3D model. These may be attributed to the fact that with 2D model the lateral components of vectors of seepage velocity are ignored. In the current case, the rate of increase of discharge flux due to dissolution of gypsum veins was obtained to be a third-order function of the aperture width. In spite of the fact that the grout curtain is designed to be about 170 m deep, however, complete dissolve of gypsum will severely increase the discharge flux through the foundation ground.

关键词： Upper Gotvand Dam     seepage analysis     gypsum veins     3D model     discharge flux    

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Methanation and chemolitrophic nitrogen removal by an anaerobic membrane bioreactor coupled partial nitrification

《环境科学与工程前沿（英文）》 2023年 第17卷 第6期 doi: 10.1007/s11783-023-1668-2

摘要：

● Efficient carbon methanation and nitrogen removal was achieved in AnMBR-PN/A system.

关键词： Anaerobic membrane bioreactor     Partial nitrification/Anammox     Carbon separation     Chemolitrophic nitrogen removal    

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“Partial pressures” of humid air in wide pressure and temperature ranges

Zidong WANG, Hanping CHEN, Shilie WENG

《能源前沿（英文）》 2013年 第7卷 第4期   页码 511-517 doi: 10.1007/s11708-013-0281-7

摘要： “Partial pressure” in humid air is a question very much concerned by scientists and no satisfactory answer has been found to date. This paper proposes a novel method to obtain the “partial pressures” of the water vapor and dry air in humid air. The results obtained by the proposed method are quite different from that obtained by Dalton’s partial pressure law. The fundamental behaviors of water vapor and dry air are studied in depth in wide pressure and temperature ranges. Semi-permeable membrane models are proposed and applied for both saturated and unsaturated humid air. “Improvement factors” are developed to quantitatively describe the magnitude of the interaction between dissimilar molecules. One discovery is that the “partial pressure” of the water vapor in saturated humid air equals , rather than ( · ) which was formerly believed. The other is that the interaction between dissimilar molecules may be omitted when temperature is above “cutting-off temperature” for unsaturated humid air. This paper satisfactorily answers the quest of “partial pressures” in humid air from a new perspective.

关键词： partial pressure     Dalton’s partial pressure law     humid air     saturated     unsaturated    

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Permeability analysis and seepage process study on crystal layer in melt crystallization with fractal

Xiaobin JIANG, Baohong HOU, Yongli WANG, Jingkang WANG

《化学科学与工程前沿（英文）》 2011年 第5卷 第4期   页码 435-441 doi: 10.1007/s11705-011-1139-3

摘要： In this paper a porous media seepage model was applied to analyze the permeability and study the seepage process of crystal pillar formed in the preparation of electronic grade phosphoric acid (EGPA). By inspecting the seeping process, the structure parameter of crystal pillar could be obtained. Two basic ideal models (perfectly separated model and perfectly connected model) were presented and a characterized factor was introduced to modify the model. A good simulation result was obtained which met the experiment result well. The relationship between and permeability were also discussed. The characterized factor showed potential application on optimizing process.

关键词： melt crystallization     porous media     fractal     permeability     hyperpure material     simulation    

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Application of entropy-based fuzzy matter-element analysis in seepage monitoring of RCC dam

Chongshi GU, Zhijun ZHANG, Xin CAI, Yue HOU

《结构与土木工程前沿（英文）》 2011年 第5卷 第1期   页码 105-111 doi: 10.1007/s11709-010-0015-4

摘要： Taking account of the fuzzy results of the seepage monitoring analysis of roller compacted concrete (RCC) dam and uncertainties of the individual indicator evaluation, the fuzzy matter-element model of seepage monitoring of RCC dam analysis has been established with the use of the fuzzy matter-element analysis theory and the concept of euclid approach degree. The use of entropy theory can calculate the weighting factor through the disorder utility values of the information reflected by the data itself, which can effectively avoid the problems of weight distribution and uncertainties of subjective judgments of the seepage monitoring analysis of roller compacted concrete dam. And further the example shows that the analysis of entropy-based fuzzy matter-element analysis model of the seepage monitoring of roller compacted concrete dam is in accordance with the actual situation, which verifies the effectiveness of the method.

关键词： information entropy     fuzzy matter-element     roller compacted concrete (RCC) dam     seepage analysis    

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Methane partial oxidation over NiO-MgO/Ce

Piyawat PUE-ON, Vissanu MEEYOO, Thirasak RIRKSOMBOOON

《化学科学与工程前沿（英文）》 2013年 第7卷 第3期   页码 289-296 doi: 10.1007/s11705-013-1345-2

摘要： Methane partial oxidation (MPO) is considered as an alternative method to produce hydrogen because it is an exothermic reaction to afford a suitable H /CO ratio of 2. However, carbon deposition on a catalyst is observed as a major cause of catalyst deactivation in MPO. In order to find suitable catalysts that prevent the carbon deposition, NiO-MgO/Ce Zr O (CZO) supported catalysts were prepared via the co-impregnation (C) and sequential incipient wetness impregnation (S) methods. The amount of Ni loading was fixed at 15 wt-% whereas the amount of MgO loading was varied from 5 to 15 wt-%. The results revealed that the addition of MgO shifted the light-off temperatures to higher temperatures. This is because the Ni surface was partially covered with MgO, and the strong interaction between NiO and NiMgO over CZO support led to the difficulty in reducing NiO to active Ni and thus less catalytic activity. However, among the catalysts tested, the 15Ni5Mg/CZO (S) catalyst exhibited the best catalytic stability for MPO after 18 h on stream at 750°C. Moreover, this catalyst had a better resistance to carbon deposition due to its high metallic Ni dispersion at high temperature.

关键词： methane partial oxidation     NiO     ceria-zirconia     MgO     mixed oxide solid solution    

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Enhanced nutrients removal from municipal wastewater through biological phosphorus removal followed by partial

Yandong Yang,Liang Zhang,Hedong Shao,Shujun Zhang,Pengchao Gu,Yongzhen Peng

《环境科学与工程前沿（英文）》 2017年 第11卷 第2期 doi: 10.1007/s11783-017-0911-0

摘要： EBPR and PN/A were combined to enhance nutrients removal from municipal wastewater. High effluent quality of 0.25 mg TP?L and 10.8 mg TN?L was obtained. Phosphorus and nitrogen removal was achieved in two separated units. A proper post-anoxic phase improved the nitrogen removal performance of PN/A unit. Conventional biological removal of nitrogen and phosphorus is usually limited due to the lack of biodegradable carbon source, therefore, new methods are needed. In this study, a new alternative consisting of enhanced biological phosphorus removal (EBPR) followed by partial nitritation-anammox (PN/A), is proposed to enhance nutrients removal from municipal wastewater. Research was carried out in a laboratory-scale system of combined two sequencing batch reactors (SBRs). In SBR1, phosphorus removal was achieved under an alternating anaerobic-aerobic condition and ammonium concentration stayed the same since nitrifiers were washed out from the reactor under short sludge retention time of 2–3 d. The remaining ammonium was further treated in SBR2 where PN/A was established by inoculation. A maximum of nitrogen removal rate of 0.12 kg N?m ?d was finally achieved. During the stable period, effluent concentrations of total phosphorus and total nitrogen were 0.25 and 10.8 mg?L , respectively. This study suggests EBPR-PN/A process is feasible to enhance nutrients removal from municipal wastewater of low influent carbon source.

关键词： Phosphorus removal     Partial nitrification     Anammox     Municipal wastewater    

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Partial liver transplantation

null

《医学前沿（英文）》 2011年 第5卷 第1期   页码 1-7 doi: 10.1007/s11684-010-0105-7

摘要：

Partial liver transplantation, including reduced-size liver transplantation, split liver transplantation, and living donor liver transplantation, has been developed with several innovative techniques because of donor shortage. Reduced-size liver transplantation is based on Couinaud’s anatomical classification, benefiting children and small adult recipients but failing to relieve the overall donor shortage. Split liver transplantation provides chances to two or even more recipients when only one liver graft is available. The splitting technique must follow stricter anatomical and physiological criteria either ex situ or in situto ensure long-term quality. The first and most important issue involving living donor liver transplantation is donor safety. Before surgery, a series of donor evaluations—including anatomical, liver volume, and liver function evaluations—is indispensable, followed by ethnic agreement. At different recipient conditions, auxiliary liver transplantation and auxiliary partial orthotopic liver transplantation, which employ piggyback techniques, are good alternatives. Partial liver transplantation enriches the practice and knowledge of the transplant society.

关键词： partial liver transplantation     reduced-size liver transplantation     split liver transplantation     living donor liver transplantation    

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标题 作者 时间 类型 操作

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

期刊论文

Chemically reactive solute transfer in a boundary layer slip flow along a stretching cylinder

Swati Mukhopadhyay

期刊论文

环境同位素示踪方法研究新安江右坝肩绕坝渗流

陈建生,刘建刚,董海洲,陈亮

期刊论文

Foundations bearing capacity subjected to seepage by the kinematic approach of the limit analysis

Mehdi VEISKARAMI, Ghasem HABIBAGAHI

期刊论文

Estimation of photolysis half-lives of dyes in a continuous-flow system with the aid of quantitative

Davoud BEIKNEJAD,Mohammad Javad CHAICHI

期刊论文

Surficial stability analysis of soil slope under seepage based on a novel failure mode

期刊论文

Quantification of seepage in a multi-layered disconnected river-aquifer system

Jiang LI, Haizhu HU, Xiaomin MAO, Yi LIU

期刊论文

Seepage analysis of Upper Gotvand Dam concerning gypsum karstification (2D and 3D approaches)

Jamshid SADREKARIMI, Majid KIYANI, Behnam FAKHRI, Mohammad Javad VAHDATIRAD, Amin BARARI

期刊论文

Methanation and chemolitrophic nitrogen removal by an anaerobic membrane bioreactor coupled partial nitrification

期刊论文

“Partial pressures” of humid air in wide pressure and temperature ranges

Zidong WANG, Hanping CHEN, Shilie WENG

期刊论文

Permeability analysis and seepage process study on crystal layer in melt crystallization with fractal

Xiaobin JIANG, Baohong HOU, Yongli WANG, Jingkang WANG

期刊论文

Application of entropy-based fuzzy matter-element analysis in seepage monitoring of RCC dam

Chongshi GU, Zhijun ZHANG, Xin CAI, Yue HOU

期刊论文

Methane partial oxidation over NiO-MgO/Ce

Piyawat PUE-ON, Vissanu MEEYOO, Thirasak RIRKSOMBOOON

期刊论文

Enhanced nutrients removal from municipal wastewater through biological phosphorus removal followed by partial

Yandong Yang,Liang Zhang,Hedong Shao,Shujun Zhang,Pengchao Gu,Yongzhen Peng

期刊论文

Partial liver transplantation

null

期刊论文