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High-gravity intensified iron-carbon micro-electrolysis for degradation of dinitrotoluene

《化学科学与工程前沿（英文）》 2023年 第17卷 第10期   页码 1595-1605 doi: 10.1007/s11705-022-2204-9

摘要： The application of iron–carbon (Fe–C) micro-electrolysis to wastewater treatment is limited by the passivation potential of the Fe–C packing. In order to address this problem, high-gravity intensified Fe–C micro-electrolysis was proposed in this study for degradation of dinitrotoluene wastewater in a rotating packed bed (RPB) using commercial Fe–C particles as the packing. The effects of reaction time, high-gravity factor, liquid flow rate and initial solution pH were investigated. The degradation intermediates were determined by gas chromatography-mass spectrometry, and the possible degradation pathways of nitro compounds by Fe–C micro-electrolysis in RPB were also proposed. It is found that under optimal conditions, the removal rate of nitro compounds reaches 68.4% at 100 min. The removal rate is maintained at approximately 68% after 4 cycles in RPB, but it is decreased substantially from 57.9% to 36.8% in a stirred tank reactor. This is because RPB can increase the specific surface area and the renewal of the liquid–solid interface, and as a result the degradation efficiency of Fe–C micro-electrolysis is improved and the active sites on the Fe–C surface can be regenerated for continuous use. In conclusion, high-gravity intensified Fe–C micro-electrolysis can weaken the passivation of Fe–C particles and extend their service life.

关键词： high-gravity technology     rotating packed bed     Fe–C micro-electrolysis     dinitrotoluene wastewater     active sites    

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卫星重力梯度数据用于精化地球重力场的研究

宁津生,罗志才,陈永奇

《中国工程科学》 2002年 第4卷 第7期   页码 23-28

摘要：

确定厘米级大地水准面和发展超高阶地球重力场模型是现代物理大地测量的主要科学目标之一。卫星重力梯度测量的实现将为这一目标做出重大贡献。文章着重评述这一领域的研究进展，并讨论利用卫星重力梯度数据精化地球重力场的若干理论和方法问题。

关键词： 卫星重力梯度测量     卫星重力梯度边值问题     地球重力场模型     大地水准面    

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Stability analysis on Tingzikou gravity dam along deep-seated weak planes during earthquake

Weiping HE, Yunlong HE

《结构与土木工程前沿（英文）》 2012年 第6卷 第1期   页码 69-75 doi: 10.1007/s11709-012-0146-x

摘要： The stability of a gravity dam against sliding along deep-seated weak planes is a universal and important problem encountered in the construction of dams. There is no recommended method for stability analysis of the dam on deep-seated weak planes under earthquake condition in Chinese design codes. Taking Tingzikou dam as an example, the research in this paper is focused on searching a proper way to evaluate the seismic safety of the dam against sliding along deep-seated weak planes and the probable failure modes of dam on deep-seated weak planes during earthquake. It is concluded that there are two probable failure modes of the dam along the main weak geological planes in the foundation. In the first mode, the concrete tooth under the dam will be cut and then the dam together with part foundation will slide along the muddy layer; in the second mode, the dam together with part foundation will slide along the path consist of the weak rock layer under the tooth and the muddy layer downstream the tooth. While there is no geological structure planes to form the second slip surface, the intersection of the main and the second slip surface is 40 to 80 m downstream from dam toe, and the angle between the second slip surface and the horizontal plane probably be 25 to 45 degrees.

关键词： gravity dam     deep-seated weak planes     stability against sliding     earthquake    

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A comprehensive simulation approach for pollutant bio-transformation in the gravity sewer

Nan Zhao, Huu Hao Ngo, Yuyou Li, Xiaochang Wang, Lei Yang, Pengkang Jin, Guangxi Sun

《环境科学与工程前沿（英文）》 2019年 第13卷 第4期 doi: 10.1007/s11783-019-1144-1

摘要：

A comprehensive pollutant transformation model for sewer systems is established.

The model comprises fermentation, sulfate reduction and ammonification processes.

Biochemical reactions related to distinct carbon sources are depicted in the model.

Pollutant transformation is attributed to different biochemical reaction processes.

关键词： Gravity sewer     Modeling     Pollutant transformation     Biochemical reaction process    

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Evaluation of seismic reliability of gravity dam-reservoir-inhomogeneous foundation coupled system

Hamid Taghavi GANJI, Mohammad ALEMBAGHERI, Mohammad Houshmand KHANEGHAHI

《结构与土木工程前沿（英文）》 2019年 第13卷 第3期   页码 701-715 doi: 10.1007/s11709-018-0507-1

摘要： The seismic performance of gravity dam-reservoir-foundation coupled system is investigated utilizing probabilistic approach. In this research, the uncertainties associated with modeling parameters are incorporated in nonlinear response history simulations to realistically quantify their effects on the seismic performance of the system. The methodology is applied to Pine Flat gravity dam and the foundation is considered to be inhomogeneous assuming a constant spatial geometry but with various rock material properties. The sources of uncertainty are taken into account in the reliability analysis using Latin Hypercube Sampling procedure. The effects of the deconvolution process, number of samples, and foundation inhomogeneity are investigated.

关键词： gravity dams     dam-reservoir-foundation interaction     seismic reliability     inhomogeneous foundation     earthquake deconvolution    

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mechanism of nitrobenzene degradation by hydroxyl radicals-based ozonation process enhanced by high gravity

Weizhou Jiao, Shengjuan Shao, Peizhen Yang, Kechang Gao, Youzhi Liu

《化学科学与工程前沿（英文）》 2021年 第15卷 第5期   页码 1197-1205 doi: 10.1007/s11705-020-1998-6

摘要： This study investigated the indirect oxidation of nitrobenzene (NB) by hydroxyl radicals (·OH) in a rotating packed bed (RPB) using competitive kinetics method with -nitrochlorobenzene as a reference compound. The rate constants of NB with ·OH are calculated to be between (1.465±0.113) × 10 L/(mol·s) and (2.497±0.192) × 10 L/(mol·s). The experimental data are fitted by the modified Arrhenius equation, where the activation energy is 4877.74 J/mol, the order of NB concentration, rotation speed, and initial pH is 0.2425, 0.1400 and 0.0167, respectively. The ozonation process of NB could be enhanced by RPB, which is especially effective for highly concentrated NB-containing wastewater under alkaline conditions. The high gravity technology can accelerate ozone mass transfer and self-decomposition of ozone to produce more ·OH, resulting in an increase in the indirect oxidation rate of NB by ·OH and consequently effective degradation of NB in wastewater.

关键词： high gravity technology     hydroxyl radicals     nitrobenzene     reaction kinetics    

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Hazard potential of zones of weakness in gravity dams under impact loading conditions

Herbert LINSBAUER

《结构与土木工程前沿（英文）》 2011年 第5卷 第1期   页码 90-97 doi: 10.1007/s11709-010-0008-3

摘要： Dam constructions worldwide are designed and constructed in view of the strictest safety aspects for all static and dynamic load cases. As experience shows, however, formation of cracks in the “homogeneos concrete” as well as unsatisfactory compound behavior of lift joints are not to be excluded. These zones of weakness especially on the upstream side of the dam— exposed to high water pressure (static and dynamic)— represent an increased risk of safety. The main investigation, apart from the computation of the dynamic effects on the dam as a global structure, focuses on the stability analysis of a pressure-water filled crack configuration subjected to “dynamic loading” in the form of seismic action on the dam-reservoir-system and alternatively by “impact spot-loading” within sectors of the reservoir. A fracture mechanics based analysis shows an excessive potential of damage for the afflicted structure.

关键词： dam-reservoir     earthquake     impact     cracking     fracture mechanics    

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Earthquake analysis of arch and gravity dams including the effects of foundation inhomogeneity

LIN Gao, DU Jianguo, HU Zhiqiang

《结构与土木工程前沿（英文）》 2007年 第1卷 第1期   页码 41-50 doi: 10.1007/s11709-007-0004-4

摘要： Dam-foundation interaction plays an important role in the design of earthquake-resistant concrete arch and gravity dams. Geological conditions of the dam canyon are usually very complicated; however, in the literature, the damfoundation interaction analysis is often carried out based on the premise of a homogeneous unbounded foundation. In this paper, the effect of foundation inhomogeneity on the seismic response of arch and gravity dams was studied by means of scaled boundary finite element method (SBFEM). In order to satisfy the similarity requirement of SBFEM and simplify the computational effort, a subdomain approach and a conical representation of an unbounded foundation were proposed. The way of partitioning the domain and the selection of open angle and bottom radius of the cone model on the accuracy of the result were examined. Numerical examples show that the proposed approach is rational and efficient. Cases of foundation inhomogeneity with stiffness varying in accordance with an exponential function along the radial direction, and cases of foundation inhomogeneity with stiffness discontinuity and with weak interlayer strata on the earthquake response of concrete arch dams as well as gravity dams were analyzed. It was found that a homogeneous idealization of the unbounded foundation may sometimes greatly underestimate the maximum earthquake stress response of the dam. Therefore, taking into account the effect of foundation inhomogeneity for the earthquake safety assessment of concrete arch and gravity dams has great significance.

关键词： selection     interlayer     damfoundation interaction     Geological     computational    

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New method for efficient control of hydrogen sulfide and methane in gravity sewers: Combination of NaOH

《环境科学与工程前沿（英文）》 2022年 第16卷 第6期 doi: 10.1007/s11783-021-1509-0

摘要：

• The combination of NaOH and nitrite was used to control harmful gas in sewers.

关键词： Sewer corrosion     Sulfide control     Combination treatment     NaOH     Nitrite    

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Seismic analysis of semi-gravity RC cantilever retaining wall with TDA backfill

Il-Sang AHN, Lijuan CHENG

《结构与土木工程前沿（英文）》 2017年 第11卷 第4期   页码 455-469 doi: 10.1007/s11709-017-0392-z

摘要： The seismic behavior of Tire Derived Aggregate (TDA) used as backfill material of 6.10 m high retaining walls was investigated based on nonlinear time-history Finite Element Analysis (FEA). The retaining walls were semi-gravity reinforced concrete cantilever type. In the backfill, a 2.74 m thick conventional soil layer was placed over a 3.06 m thick TDA layer. For comparison purpose, a conventional all soil-backfill model was also developed, and the analysis results from the two models under the Northridge and Takatori earthquakes were compared. The FEA results showed that both models did not experience major damage in the backfill under the Northridge earthquake. However, under the Takatori earthquake, the TDA-backfill model developed substantially large displacement in the retaining walls and in the backfill compared with the soil-backfill model. Regions of large plastic strain were mainly formed in the TDA layer, and the soil over the TDA layer did not experience such large plastic strain, suggesting less damage than the soil-backfill model. In addition, the acceleration on the backfill surface of the TDA-backfill model decreased substantially compared with the soil-backfill model. If an acceleration sensitive structure is placed on the surface of the backfill, the TDA backfill may induce less damage to it.

关键词： TDA (Tire Derived Aggregate)     scrap tires     retaining wall     seismic analysis     Finite Element Analysis    

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High-gravity-assisted emulsification for continuous preparation of waterborne polyurethane nanodispersion

Weihong Zhang, Dan Wang, Jie-Xin Wang, Yuan Pu, Jian-Feng Chen

《化学科学与工程前沿（英文）》 2020年 第14卷 第6期   页码 1087-1099 doi: 10.1007/s11705-019-1895-z

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Several issues to be considered for long-term better behavior of concrete gravity dams

Jinsheng JIA,

《结构与土木工程前沿（英文）》 2010年 第4卷 第1期   页码 40-46 doi: 10.1007/s11709-010-0006-5

摘要： Along with economic, social quick development and urbanization, dams and reservoirs are of strategic importance for flood control, water supply, electricity production, irrigation, etc., both for developed countries and for developing countries. Climate change is a new challenging issue to be considered which will speed up the development of hydropower in developing countries. More and more attention will be paid on the long-term better behavior of dams to guarantee the safety of the people involved and the better development of the world. There are about 50000 old dams in the world and a lot of them have been completed and operated for more than 50 years. However, how do we evaluate the dams’ safety? How do we make the decision to do rehabilitation work or to rebuild a new dam based on evaluation results? The life span and the real safety status of old dams becomes a challenging task for the dam society, especially for China because it has more than 6000 dams to be evaluated and rehabilitated within the next few years. Based on the investigation of the Fengman gravity dam, which is 91.7 m high, operated since 1943 and suffered uplift pressure, freeze and thaw problems, etc., discussions on the life span evaluation of old concrete gravity dams have been made. The reasonable coefficient of dam safety has been discussed. The social decision for the final choice after comprehensive studies has been introduced.

关键词： dam safety     economic life span     structural life span     environmental life span     rehabilitation     social decision    

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of seismic wave propagation in massed medium on rate-dependent anisotropic damage growth in concrete gravity

Alireza DANESHYAR, Hamid MOHAMMADNEZHAD, Mohsen GHAEMIAN

《结构与土木工程前沿（英文）》 2021年 第15卷 第2期   页码 346-363 doi: 10.1007/s11709-021-0694-z

摘要： Seismic modeling of massive structures requires special caution, as wave propagation effects significantly affect the responses. This becomes more crucial when the path-dependent behavior of the material is considered. The coexistence of these conditions renders numerical earthquake analysis of concrete dams challenging. Herein, a finite element model for a comprehensive nonlinear seismic simulation of concrete gravity dams, including realistic soil–structure interactions, is introduced. A semi-infinite medium is formulated based on the domain reduction method in conjunction with standard viscous boundaries. Accurate representation of radiation damping in a half-space medium and wave propagation effects in a massed foundation are verified using an analytical solution of vertically propagating shear waves in a viscoelastic half-space domain. A rigorous nonlinear finite element model requires a precise description of the material response. Hence, a microplane-based anisotropic damage–plastic model of concrete is formulated to reproduce irreversible deformations and tensorial degeneration of concrete in a coupled and rate-dependent manner. Finally, the Koyna concrete gravity dam is analyzed based on different assumptions of foundation, concrete response, and reservoir conditions. Comparison between responses obtained based on conventional assumptions with the results of the presented comprehensive model indicates the significance of considering radiation damping and employing a rigorous constitutive material model, which is pursued for the presented model.

关键词： soil–structure interaction     massed foundation     radiation damping     anisotropic damage    

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quantification of stability and damage detection parameters of coupled hydrodynamic-ground motion in concrete gravity

Nazim Abdul NARIMAN, Tom LAHMER, Peyman KARAMPOUR

《结构与土木工程前沿（英文）》 2019年 第13卷 第2期   页码 303-323 doi: 10.1007/s11709-018-0462-x

摘要： In this paper, models of the global system of the Koyna dam have been created using ABAQUS software considering the dam-reservoir-foundation interaction. Non coupled models and the coupled models were compared regarding the horizontal displacement of the dam crest and the differential settlement of the dam base in clay foundation. Meta models were constructed and uncertainty quantification process was adopted by the support of Sobol’s sensitivity indices considering five uncertain parameters by exploiting Box-Behnken experimental method. The non coupled models results determined overestimated predicted stability and damage detection in the dam. The rational effects of the reservoir height were very sensitive in the variation of the horizontal displacement of the dam crest with a small interaction effect with the beta viscous damping coefficient of the clay foundation. The modulus of elasticity of the clay foundation was the decisive parameter regarding the variation of the differential settlement of the dam base. The XFEM approach has been used for damage detection in relation with both minimum and maximum values of each uncertain parameter. Finally the effects of clay and rock foundations were determined regarding the resistance against the propagation of cracks in the dam, where the rock foundation was the best.

关键词： massed foundation     hydrodynamic pressure     Box-Behnken method     meta model     Sobol’s sensitivity indices    

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uncoupler, 3,3′,4′,5-tetrachlorosalicylanilide addition for sludge reduction and fouling control in a gravity-driven

An Ding, Yingxue Zhao, Huu Hao Ngo, Langming Bai, Guibai Li, Heng Liang, Nanqi Ren, Jun Nan

《环境科学与工程前沿（英文）》 2020年 第14卷 第6期 doi: 10.1007/s11783-020-1275-4

摘要： Abstract • Effects of metabolic uncoupler TCS on the performances of GDMBR were evaluated. • Sludge EPS reduced and transformed into dissolved SMP when TCS was added. • Appropriate TCS increased the permeability and reduced cake layer fouling. • High dosage aggravated fouling due to compact cake layer with low bio-activity. The gravity-driven membrane bioreactor (MBR)system is promising for decentralized sewage treatment because of its low energy consumption and maintenance requirements. However, the growing sludge not only increases membrane fouling, but also augments operational complexities (sludge discharge). We added the metabolic uncoupler 3,3′,4′,5-tetrachlorosalicylanilide (TCS) to the system to deal with the mentioned issues. Based on the results, TCS addition effectively decreased sludge ATP and sludge yield (reduced by 50%). Extracellular polymeric substances (EPS; proteins and polysaccharides) decreased with the addition of TCS and were transformed into dissolved soluble microbial products (SMPs) in the bulk solution, leading to the break of sludge flocs into small fragments. Permeability was increased by more than two times, reaching 60–70 L/m2/h bar when 10–30 mg/L TCS were added, because of the reduced suspended sludge and the formation of a thin cake layer with low EPS levels. Resistance analyses confirmed that appropriate dosages of TCS primarily decreased the cake layer and hydraulically reversible resistances. Permeability decreased at high dosage (50 mg/L) due to the release of excess sludge fragments and SMP into the supernatant, with a thin but more compact fouling layer with low bioactivity developing on the membrane surface, causing higher cake layer and pore blocking resistances. Our study provides a fundamental understanding of how a metabolic uncoupler affects the sludge and bio-fouling layers at different dosages, with practical relevance for in situ sludge reduction and membrane fouling alleviation in MBR systems.

关键词： Gravity-driven membrane (GDM)     Energy uncoupling     Permeability     Sludge reduction     Membrane fouling     Fouling layer    

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标题 作者 时间 类型 操作

High-gravity intensified iron-carbon micro-electrolysis for degradation of dinitrotoluene

期刊论文

卫星重力梯度数据用于精化地球重力场的研究

宁津生,罗志才,陈永奇

期刊论文

Stability analysis on Tingzikou gravity dam along deep-seated weak planes during earthquake

Weiping HE, Yunlong HE

期刊论文

A comprehensive simulation approach for pollutant bio-transformation in the gravity sewer

Nan Zhao, Huu Hao Ngo, Yuyou Li, Xiaochang Wang, Lei Yang, Pengkang Jin, Guangxi Sun

期刊论文

Evaluation of seismic reliability of gravity dam-reservoir-inhomogeneous foundation coupled system

Hamid Taghavi GANJI, Mohammad ALEMBAGHERI, Mohammad Houshmand KHANEGHAHI

期刊论文

mechanism of nitrobenzene degradation by hydroxyl radicals-based ozonation process enhanced by high gravity

Weizhou Jiao, Shengjuan Shao, Peizhen Yang, Kechang Gao, Youzhi Liu

期刊论文

Hazard potential of zones of weakness in gravity dams under impact loading conditions

Herbert LINSBAUER

期刊论文

Earthquake analysis of arch and gravity dams including the effects of foundation inhomogeneity

LIN Gao, DU Jianguo, HU Zhiqiang

期刊论文

New method for efficient control of hydrogen sulfide and methane in gravity sewers: Combination of NaOH

期刊论文

Seismic analysis of semi-gravity RC cantilever retaining wall with TDA backfill

Il-Sang AHN, Lijuan CHENG

期刊论文

High-gravity-assisted emulsification for continuous preparation of waterborne polyurethane nanodispersion

Weihong Zhang, Dan Wang, Jie-Xin Wang, Yuan Pu, Jian-Feng Chen

期刊论文

Several issues to be considered for long-term better behavior of concrete gravity dams

Jinsheng JIA,

期刊论文

of seismic wave propagation in massed medium on rate-dependent anisotropic damage growth in concrete gravity

Alireza DANESHYAR, Hamid MOHAMMADNEZHAD, Mohsen GHAEMIAN

期刊论文

quantification of stability and damage detection parameters of coupled hydrodynamic-ground motion in concrete gravity

Nazim Abdul NARIMAN, Tom LAHMER, Peyman KARAMPOUR

期刊论文

uncoupler, 3,3′,4′,5-tetrachlorosalicylanilide addition for sludge reduction and fouling control in a gravity-driven

An Ding, Yingxue Zhao, Huu Hao Ngo, Langming Bai, Guibai Li, Heng Liang, Nanqi Ren, Jun Nan

期刊论文