Exploring the Linkage between Land Use Type and Stream Water Quality of an Estuarine Island Applying GWR Model: A Case Study of Chongming, Shanghai

To understand the spatial correlations between land use type and water quality of an estuarine island is particularly essential to maintain its original ecological environment. Chongming Island is experiencing a rapid urbanization and agriculture land sprawl during the last decades, especially with the growth of agro-industry and the extension of old style residences. As a consequence, surface run-off from agricultural activities and domestic sewage discharge has a various linkage with stream water quality on the island. This study applied ageographical weight regression model approach to recognize the significance of the relationship between water quality and multiple land use. We also evaluated their spatial correlations which normally hidden from other traditional regression methods. The results reveal that the water quality of less-developed areas on Chongming Island was easily affected by land use types compared with other regions, TN, TP, BOD5, COD were shown as the most significant responses among all the water quality indicators. Green land and water area had a reduced effect on nutrients, expansion of industrial land would continuously make a contribution of pollutants to the water environment. Suggestions should therefore be taken into consideration during the process of development planning, in order to prevent water contamination.

单圆盾构法错缝隧道结构变形的健康评估综合分析（英文）

结构变形是隧道结构性能评估的重要依据,然而由于隧道结构具有纵向线性、横向截面大的特点,难以通过室内模型试验或者远行试验来研究结构变形与结构损伤的关系。以长三角某单圆盾构法错缝隧道事故案例为依托,通过研究结构变形、管片裂缝、接缝变形等病害特点及与隧道截面椭圆度的相关性,综合分析了隧道病害类型及检测方法。研究结果表明,椭圆度与各隧道病害指标均表现出很强的相关性,可以用来描述隧道病害程度的重要指标。若椭圆度小于0.5%,则隧道可以被认为处于完全健康的状态。但是如果椭圆度超过0.77%,则隧道处于严重的破坏状态。成果对完善盾构隧道相关规范,以及对形成运营期隧道维修养护标准有重要的意义。

A simple permanent deformation model of rockfill materials

Existing experimental results have shown that using a semi-log linear relationship between the permanent volumetric strain and cyclic number underestimates the volumetric deformation of rockfill materials with a large cyclic number, and that the error increases with the confining pressure. The existing permanent deformation models are not suitable for the seismic safety analysis of high dams during strong earthquakes. In this study, a series of large-scale triaxial cyclic loading tests of rockfill materials were performed, and a new permanent deformation model of rockfill materials was developed and validated with three kinds of rockfill materials. The results show that the proposed model can properly reflect the general features of the permanent deformation of rockfill materials. The main features of the model are as follows:(1) relations between the cyclic number and permanent volumetric/shear strain are described by hyperbolic functions, which can avoid underestimating the volumetric deformation occurring during strong earthquakes;(2) the model can capture the effect of the mean effective stress on the permanent volumetric strain, with greater confining pressure correlating to greater permanent volumetric deformation, and the permanent volumetric strain under low confining pressure near the dam crest can be well represented; and(3) the model can reflect the effect of the consolidation stress ratio on the permanent shear strain.

Co-pyrolysis characteristics of typical components of waste plastics in a falling film pyrolysis reactor

Waste plastics mainly come from MSW and usually exist in the form of mixed plastics. During the co-pyrolysis process of mixed plastics, various plastic components have different physicochemical properties and reaction mechanisms. Considering the high viscosity and low thermal conductivity of molten plastics, a falling film pyrolysis reactor was selected to explore the rapid co-pyrolysis process of typical plastic components(PP, PE and PS).The oil and gas yields and the compositions of pyrolysis products of the three components under different ratios at pyrolysis temperatures were analyzed to explore the co-pyrolysis characteristics of PP, PE, and PS. The study is of great significance to the recycling of waste plastics.

Study on degradation mechanism of aniline solution by potassium ferrate

研究了高铁酸钾投加量、初始pH及苯胺初始浓度对苯胺降解效果的影响。结果表明，苯胺废水的COD去除率照高铁酸钾投加量和苯胺初始浓度的增大而升高，而初始pH对COD去除率影响不明显。对高铁酸钾降解苯胺废水后的产物进行了气相色谱／质谱（GC／MS）分析，在此基础上详细探讨了高铁酸钾降解苯胺的机制。

信号处理及支持向量机在沥青路面横缝检测中的应用

基于振动的路面状况监测应用越来越广泛,然而,该类方法多关注平整度及明显异常,缺乏针对不显著的横向裂缝的研究。因此,本文借助信号处理技术及支持向量机(SVM),提出一种新颖的基于车辆振动的横向裂缝识别方法。对横向开裂路段和无裂缝路段的车辆振动信号在时域、频域和小波域进行了分析,旨在找到可以区分路面开裂与否的振动信号参数。这些参数共形成了8个SVM分类模型,保留具有最高准确度和F1分数的分类模型,该模型考虑的特征参数包括车辆速度、加速度极差、相对标准差、最大傅里叶系数和小波系数,据此建立了一个开裂-未开裂的分类器。然后在2292个路段上应用了该分类器,结果显示,识别准确度和F1分数分别为97.25%和85.25%。本文提出的横缝识别方法与已有的基于智能手机识别IRI和其他路面病害的方法可形成一个综合路面状况识别系统。

Effect of PCEs with Different Functional Groups on the Performance of Cement Paste

The adsorption behaviors and dispersing properties of polycarboxylate superplasticizer(PCE) with different functional groups were systematically analyzed to reveal the theory and methods of modifying PCE molecular structures and regulating PCE performances. By substituting carboxylic groups with sulfonic groups, ester groups or acylamino groups, respectively, modified PCEs with different functional groups were synthesized. Results show that introducing low amount of ester groups or sulfonic groups into the PCE molecules has no negative effects on the fluidity of cement paste, while introducing acylamino groups into PCE molecules significantly weakens the fluidity of cement paste. At low amount(when the molar ratio of sodium methallyl sulfonate to TPEG is lower than 0.4), the rapid adsorption of sulfonic groups onto the cement particles contributes to the high dispersing performance of the sulfonic group modified PCEs. When the substitution ratio of acrylic acid by sulfonic acid is higher than 0.4, the viscosity and the yield stress of cement paste increases sharply. Redundant sulfonic groups lead to the excessive charge density of the PCE, which contributes to the inhomogeneous adsorption on the cement grains and hence results in the decline of the dispersing performance. Substitution of carboxylic group by acylamino group or ester group slightly changes the viscosity as well as the yield stress of cement paste. Introducing sulfonic group into PCE molecule improves the adsorption behavior of PCEs, while introducing ester group or acylamino group into PCE depresses the adsorption properties.

Effects of Different States of Fe on Anaerobic Digestion:A Review

Anaerobic digestion is widely used in the treatment of industrial wastewater,excess activated sludge,municipal waste,crop straw and livestock manure,with the functions of environmental protection and energy recovery. This review summarizes and evaluates the present knowledge of effects of different states of Fe( ZVI,Fe( II),Fe( III)) on hydrogen and methane production in anaerobic digestion process. The potential promotion effects of iron oxides nanoparticles( IONPs),especially magnetite nanoparticles on anaerobic digestion are also mentioned. Fe plays important role in transporting electron,stimulating bacterial growth and increasing hydrogen and methane production rate by promoting enzyme activity. Adding Fe with different morphologies and valence states in anaerobic digestion to increase biogas( hydrogen and methane) production and enhance organic matter degradation simultaneously,which has attracted many scientists' attention in recent years. Rapid progress in this area has been made over the last few years,since Fe is essential to the fermentative hydrogen and methane production,while few is known about how Fe affects the fermentative biogas production. This review is significant to maintain the stable operation of the biogas project.

Influence of Polycarboxylate Superplasticizer on Rheological Behavior in Cement Paste

Molecular structures of polycarboxylate（PCE） superplasticizer significantly affect the rheological properties of cement paste. Consequently, we employed self-synthesized PCE copolymers with different carboxylic densities to investigate their influence on the rheological behavior of cement paste. Three typical rheological models were applied to analyze the rheological properties, including Power-law model, Bingham model as well as Herschel-Buikley model. In addition, the thixotropical performances of cement paste in the presence of PCE with different carboxylic densities were investigated. The results show that the carboxylic density of PCE greatly influences the dispersing performance of PCE superplasticizers. As carboxylic density increases, the dispersing capability of PCE improves, and P（PEG1-AA6） possesses the strongest dispersing capability, the initial fluidity and 1 h fluidity of cement paste are both the highest, and cement paste has the lowest viscosity and the smallest hysteresis loop.

Photolysis of H_2S with interior microwave discharge electrodeless lamps

微波的光性质解除与低集中在氢硫化物的反响的洞和光分解作用以内被点燃的无电极的水银灯(MDEL-Hg ) 在这份报纸被学习。实验结果显示内部 MDEL-Hg 能被最大可能利用精力利用和 H2S 的光分解作用的效率在有 7.9 mg m 的起始的 H2S 集中的试验性的条件下面是很重要的 ? 3。与 1.5 s 的住处时间，氢硫化物的移动效率是 91% ，绝对移动数量(ARA ) 是 3.24 渭 g s ? 1 并且精力消费是 58.23 mg (kW h )? 1。

Effect of aggregate gradation on low temperature performance of asphalt paving mixtures

Low temperature cracking has become one of the important factors that diminish asphalt pavement's ride quality and service life.Especially in cold region,cracking caused by low temperature is the main distress form.This paper discussed the effect of aggregate gradation on the low temperature performance in asphalt paving mixtures.A total of 11 asphalt mixtures with 11 different aggregate gradations and one asphalt binder content were studied.Volumetric properties of the coarse aggregate and asphalt mixtures showed aggregate grading has a significant impact on the degree of aggregate interlock in asphalt mixtures.A trend is existed in the low temperature performance with the change of gradation.With the aid of mathematic statistics,it indicates gradation affects the low temperature performance significantly.The findings also indicate the relationship between the degree of aggregate interlock in asphalt mixtures and the low temperature performance:With the stone-to-stone contact developed,the mixture has a high energy to resist contract and deformation at low temperature.The properties of fine aggregate and asphalt play an important part in resisting low temperature cracking in floating structure.But it provides lower energy to resist low temperature cracking compared to the skeleton structure.

Modified origin-based algorithm for traffic equilibrium assignment problems

Key tactics of origin-based user equilibrium (OUE) algorithm was studied,which involved the algorithm procedure and several implementation issues.To speed up the convergence,update policies of flows,costs and bushes were proposed.The methods of step-size searching and bush construction are proved to be practical.The modified OUE algorithm procedure was also optimized to take the advantage of multi-thread process.Convergence performances were compared with those of other algorithms by different sizes of urban transportation networks.The result shows this modified OUE algorithm is more efficient and consumes less time to achieve the reasonable relative gap in practical applications.

Impact of the Rainfall Intensity and Seepage on Slope Stability in Loess Plateau

In recent years,with the increase of traffic construction in mountainous areas in China,road slope traffic accidents have become more and more common.In addition,natural disasters such as landslides,collapses and subgrade settlements caused by rainfall,driving load,seasonal variation and groundwater distribution are frequent.In particular,rainfall is one of the most common factors leading to slope instability(landslide).Therefore,this paper proposes the seep module based on the application software Geo-studio,and analyzes the slope soil parameters and slope stability under five types of rainfall conditions:light rain(10 mm/d),moderate rain(25 mm/d),heavy rain(50 mm/d),rainstorm(100 mm/d),and torrential rain(250 mm/d).The critical safety factor under rainfall intensity is fitted with nonlinear curve by sine function.The results show that the fitting curve of rainfall intensity and safety factor on the upper slope is excellent.The residual points are evenly distributed in the belt area of±0.1,and the data basically conform to the nonlinear sine model,indicating that the curve plays an essential role in slope health diagnosis.

Effects of Organosilane-modified PCE on the Fluidity and Hydration Properties of Cement-Fly Ash Composite Binder

Effects of organosilane-modified PCE (OS-PCE) on the fluidity and the hydration properties of cement-fly ash (FA) composite binder were systematically analyzed.The experimental results show that OS-PCE possesses respectively 36.98% and 36.67% higher saturated adsorption amount on cement and FA,in comparison with ordinary PCE,and can contribute to higher fluidity of cement-FA composite binder.The addition of OS-PCE retards hydration process of cement-FA composite binder proportionally with the dosage of OS-PCE,but promotes the hydration kinetics of the composite binder.The reactivity enhancement is attributed to the well-dispersed FA by OS-PCE,which provides more nucleation sites for the reaction of heterogeneous C-S-H and enhances the contact with water to react with CH forming pozzolanic C-S-H.Well-distributed hydration products are exhibited in the hardened binder added with OS-PCE,with a large number of hydrated gels uniformly fill in the pores and gaps,which improves the compaction of the hardened structure.

Heat transfer characteristics of molten plastics in a vertical falling film reactor

The heat transfer efficiency during the pyrolysis process is a key factor to be considered in the design of pyrolysis reactors. In this study, the average apparent heat transfer characteristics of molten plastic pyrolysis in a vertical falling film reactor were explored by experiments and numerical simulation and the apparent heat transfer coefficients were determined. In addition, the temperature distribution and the thickness of the liquid film in the reactor were predicted and the influences of pyrolysis temperatures on the average apparent heat transfer coefficients were discussed.

Comparison of Geotextiles by Aeration Vacuum Rapid Dewatering Technique on Dredged Sludge

In order to accelerate the consolidation of the dredged sludge and look for an effective material for mud-water separation,the study on the comparison of geotextiles is carried on. It is based on the laboratory model test of aeration vacuum rapid mud- water separating( AVMWS) technique and evaluated by the cumulative weight of pumping water,the decrease of moisture content and the stable pumping speed. The results show that woven fabric is the best anti- clogging aeration vacuum material,followed by machine-woven fabric and non-woven fabric is the worst. The analysis has been proposed from two aspects of geotextile weaving technology and aeration vacuum condition.

From landscape urbanism to ecological urbanism:Origin and development

Based on the origin and development of landscape urbanism,with several representative cases,this paper introduces the origin of ecological urbanism,as well as the main concepts and strategies,and then compared the changes from Landscape Urbanism to Ecological Urbanism.At last,this paper discusses its enlightenment on China’s urban construction and landscape development with the focus on the actual situation in China.

SEEPAGE ANALYSIS OF LANDFILL FOUNDATIONS IN SHANGHAI LAOGANG LANDFILL PHASE IV

A complex seepage flow field with unknown free surface was formed in the Shanghai Laogang Municipal Solid Waste （MSW） Landfill by the perimeter cut-off wall around the landfill site and the Prefabricated Vertical Drains （PVD） in the foundation of landfill. First, the equivalent vertical permeability was presented based on the drainage mechanism of PVD and the related calculation method was studied to macroscopically reflect the impact of PVD on the seepage flow status of the landfill foundation. With the influence of the cut-off wall and the PVD on the infiltration of groundwater, the total inflow was classified into two parts： the lateral inflow through the cut-off wall outside the landfill, and the upward infiltration through the PVD from the foundation of the landfill. Seepage analysis was conducted using the finite element method according to the actual scenario of Laogang Landfill, and the lateral infiltration and the upward infiltration were calculated, respectively. The results show that the total inflow into the landfill area was mostly supplied by the upward infiltration through the PVD and the perimeter cut-off wall was significantly effective to depressurize the seepage pressure and to reduce the flow rate.