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Development of Features for Early Detection of Defects and Assessment of Bridge Decks

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structural Durability & Health Monitoring 2023年第4期17卷 257-281页

作者： Ahmed Silik Xiaodong Wang Chenyue Mei Xiaolei Jin Xudong Zhou Wei Zhou Congning Chen Weixing hong Jiawei Li Mingjie Mao Yuhan Liu Mohammad Noori Wael A.Altabey Nanjing Zhixing Information Technology Co. Ltd.NanjingChina Jiangsu Advance Transportation Institute NanjingChina Suzhou Highway Development Center SuzhouChina Guangdong Communications Group Co. Ltd.GuangzhouChina department of Mechanical engineering California Polytechnic State UniversitySan Luis ObispoCA93405USA School of civil engineering University of LeedsLeedsLS29JTUK department of civil {2. Faculty of Engineering SciencesNyala UniversityNyala092Sudan department of Mechanical engineering Faculty of EngineeringAlexandria UniversityAlexandria21544Egypt

Damage detection is an important area with growing interest in mechanical and structural *** of the critical issues in damage detection is how to determine indices sensitive to the structural damage and insensitive to the surrounding environmental *** damage identification indices commonly focus on structural dynamic characteristics such as natural frequencies,mode shapes,and frequency *** study aimed at developing a technique based on energy Curvature Difference,power spectrum density,correlation-based index,load distribution factor,and neutral axis shift to assess the bridge deck *** addition to tracking energy and frequency over time using wavelet packet transform,in order to further demonstrate the feasibility and validity of the proposed technique for bridge condition assessment,experimental strain data measured from two stages of a bridge in the different intervals were *** comparative analysis results of the bridge in first and second stage show changes in the proposed feature *** is concluded,these changes in the values of the proposed features can be used to assess the bridge deck performance.

关键词： structural health monitoring strain monitoring distribution factor wavelet packet transform

车辙对大空隙沥青路面横向排水影响的室内模拟测试

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东南大学学报（自然科学版） 2016年第3期46卷 584-588页

作者：陈俊孔燕黄晓明徐艳 Wang Linbing 河海大学土木与交通学院南京210098 东南大学交通学院南京210096 The Via department of civil and Environmental {2. Virginia Polytechnic Institute and State University

为了研究纵向车辙对大空隙沥青路面横向排水的影响,研发了大空隙沥青混合料渗水系数的室内测试仪,该仪器可模拟路面横坡和雨水在大空隙沥青混合料中的流动过程.采用车辙试验仪对8种类型的OGFC沥青混合料试件进行往复荷载作用来模拟车辙... 详细信息

为了研究纵向车辙对大空隙沥青路面横向排水的影响,研发了大空隙沥青混合料渗水系数的室内测试仪,该仪器可模拟路面横坡和雨水在大空隙沥青混合料中的流动过程.采用车辙试验仪对8种类型的OGFC沥青混合料试件进行往复荷载作用来模拟车辙变形,并利用研发的渗水系数测试仪,测试具有不同车辙深度的沥青混合料横向渗水系数,计算得到因车辙引起的混合料渗水系数衰减度.结果表明:车辙会明显降低大空隙沥青混合料的横向渗水系数;动稳定度与渗水系数衰减度无明显关系,而大空隙沥青混合料的车辙深度与渗水系数衰减度具有一定的线性关系,因此可作为控制渗水系数衰减的指标;增大集料的公称最大粒径、使用高黏改性沥青、增大混合料空隙率能有效降低车辙引起的排水系数衰减程度.

关键词：大空隙沥青路面车辙渗水系数测试仪渗水系数

MODELLING OF THE WAVE-CURRENT INTERACTION IN THE PEARL RIVER ESTUARY

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MODELLING OF THE WAVE-CURRENT INTERACTION IN THE PEARL RIVER...

Process Window Determination for Biofiltration by the Taguchi Method

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作者： WAI Wing-hong,Onyx LI Yok-sheung department of civil and {2. engineering The Hong Kong Polytechnic UniversityHong Kong department of civil and {2. engineering The Hong Kong Polytechnic UniversityHong Kong

＜正＞A wave propagation model based on the wave action conservation theory was developed and applied to the modelling of wave characteristics and the interaction of wave and current in the Pearl River Estuary, by coupling with a three-dimensional hydrodynamics model. The modelling results show that waves propagating from the open sea would be attenuated significantly because of sheltering by islands and shoaling. Waves incoming from the south can propagate further upstream. The tidal current generally increases the wave heights and the effect of the ebbing flow on waves is significant.

关键词： pearl river estuary 3-D modelling wave propagation wave-current interaction

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Journal of Water Resource and Protection 2012年第10期4卷 831-837页

作者： Man Chung Law hong Chua Ka Po Cheng Chi Wai Kan department of civil and Structure {2. The Hong Kong Polytechnic University Hong Kong Chin department of civil and Structure {2. The Hong Kong Polytechnic University Hong Kong China department of Industrial Centre The Hong Kong Polytechnic University Hong Kong China department of Institute of Textiles and Clothing The Hong Kong Polytechnic University Hong Kong China

Raw water from the Yantian Reservoir in Southern china was used for this study. Several process parameters of biofiltration, temperature, media, empty bed contact time, ozone dosage and concentration of geosmin and MIB, were adopted in order to determine their effects. Experiments were conducted using the Taguchi method and 9 experiments were needed to obtain the best process parameter settings and parameter effects. The results of these experiments indicate the use of biological filtration as a method of geosmin and MIB removal, to be satisfactory. In addition, the results show that temperature impacts the removal rate of both geosmin and MIB. Useful insights into the effects of the filter media on such as, empty bed contact time, ozone dosage and concentration of geosmin and MIB were also obtained.

关键词： Taste and Odor Water Quality Design of Experiment Taguchi Method

Comparative investigations of pressure waves induced by trains passing through a tunnel with different speed modes

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Journal of Central South university 2022年第8期29卷 2639-2653页

作者： ZHOU Miao-miao LIU Tang-hong XIAYu-tao LIWen-hui CHEN Zheng-wei Key Laboratory of Traffic Safety on Track of Ministry of Education School of Traffic&Transportation EngineeringCentral South UniversityChangsha 410075China Joint International Research Laboratory of Key Technology for Rail Traffic Safety Central South UniversityChangsha 410075China National&Local Joint engineering Research Centre of Safety Technology for Rail Vehicle Central South UniversityChangsha 410075China department of civil and Environmental {2. The Hong Kong Polytechnic UniversityHung HomKowloonHong KongChina

Pressure waves induced by high-speed trains passing through a tunnel have adverse effects on train structures and passenger comfort. These adverse effects can be alleviated when the train passing through the tunnel with a speed mode of deceleration. Thus, to investigate the effect of speed modes on pressure waves, three-dimensional compressible unsteady Reynolds-averaged Navier-Stokes simulations and the sliding mesh are used to simulate pressure waves on train surfaces and tunnel walls when trains passing through a tunnel with three different speed modes(a constant speed at350 km/h, a uniform deceleration from 350 to 300 km/h, and another uniform deceleration from 350 to 2.0 km/h).Compared with the constant speed, the peak-to-peak of the train surface pressure under the other two speed modes reaches a maximum difference of 11.0%. The maximum positive pressure difference of the tunnel wall under different speed modes is caused by the different attenuation of the friction effect when the train enters the tunnel, and the maximum difference is 12.8%. The difference of the maximum negative pressure on the tunnel wall is caused by the different speed and pressure wave intensity of the train arriving at the same measuring point in different speed modes,and the maximum difference is 15.8%. Hence, it can be concluded that a speed mode of deceleration for trains passing a tunnel can effectively alleviate the aerodynamic effect in the tunnel, especially for the pressure on the tunnel wall.

关键词： high-speed trains tunnel aerodynamics pressure wave deceleration

合作经济、集体劳动与农村妇女——一个华南村落的乡村旅舍实践案例

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妇女研究论丛 2017年第6期 36-47页

作者：闫红红郭燕平古学斌中山大学社会学与社会工作系广东广州510275 华南师范大学教育信息技术学院广东广州510631 香港理工大学应用社会科学系香港999077

本文通过回顾毛泽东时代集体经济的历史经验,对照改革开放以来中国农村妇女组织与合作经济的发展现状,以L社工机构(1)在一个华南农村推动的乡村旅舍项目为例,探讨新型合作经济中妇女组织培育与妇女增权的路径。文章分成三个部分:集体化... 详细信息

本文通过回顾毛泽东时代集体经济的历史经验,对照改革开放以来中国农村妇女组织与合作经济的发展现状,以L社工机构(1)在一个华南农村推动的乡村旅舍项目为例,探讨新型合作经济中妇女组织培育与妇女增权的路径。文章分成三个部分:集体化时期农村妇女的组织状况、改革开放之后中国妇女组织与合作经济的发展现状以及广东某一村庄妇女组织与合作经济的当代实践。文章认为,扎根于农村社区,采用优势资产视角以发展新型本土合作经济,将有助于实现妇女的劳动合作及妇女增权。

关键词：农村妇女合作经济妇女组织乡村旅舍妇女增权

Dynamic behaviors and mitigation measures of a train passing through windbreak transitions from ground to cutting

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Journal of Central South university 2022年第8期29卷 2675-2689页

作者： CHEN Zheng-wei LIU Tang-hong GUO Zi-jian HUO Xiao-shuai LIWen-hui XIAYu-tao department of civil and Environmental {2. The Hong Kong Polytechnic UniversityHung HomKowloonHong KongChina Key Laboratory of Traffic Safety on Track of Ministry of Education School of Traffic&Transportation EngineeringCentral South UniversityChangsha 410075China Joint International Research Laboratory of Key Technology for Rail Traffic Safety Changsha 410075China National&Local Joint engineering Research Center of Safety Technology for Rail Vehicle Changsha 410075China

In this paper,the effects of a right-angle windbreak transition(RWT)from the flat ground to cutting on train aerodynamic and dynamic responses were investigated,then a mitigation measure,an oblique structure transition(OST)was proposed to reduce the impact of RWT on the train aerodynamic and dynamic *** results showed that in the RWT region,the airflow was divided into two *** part of the airflow induced a strong backflow in the flat ground position,and the other part of the airflow induced a strong backflow in the cutting ***,there were two lateral impacts on the *** the head car with the OST,the drop ratios of the peak-to-peak values compared with RWT were 47%,40%,and 52.for the side force coefficient C_(Fy),lift force coefficient C_(Fz) and overturning moment coefficient C_(Mx),*** the peak-to-peak value of the dynamic parameters,the drop ratios of OST compared with RWT were all larger than 50%.The maximum dynamic overturning coefficients for RWT and OST were 0.75 and 0.3,respectively.

关键词： high-speed train windbreak wall crosswind CFD train aerodynamics vehicle system dynamics

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分形城市研究进展:从几何形态到网络关联

地球信息科学学报 2020年第4期22卷 827-841页

作者：张红蓝天李志林华东师范大学城市与区域科学学院上海200062 西南交通大学地球科学与环境工程学院成都611756 香港理工大学土地测量与地理资讯系香港999077

城市是人类文明最主要的聚集地,也是一个开放复杂演化巨系统,认识其空间复杂性成为城市科学研究的热点和前沿。城市研究正呈现“从位置和场所向关联和流,从物质空间向城市网络空间”的转向。人类对城市的认识也从“空间是机器”转向“... 详细信息

城市是人类文明最主要的聚集地,也是一个开放复杂演化巨系统,认识其空间复杂性成为城市科学研究的热点和前沿。城市研究正呈现“从位置和场所向关联和流,从物质空间向城市网络空间”的转向。人类对城市的认识也从“空间是机器”转向“城市有机生命体”。分形是大自然的语言和地理学第四代语言,是挖掘城市空间自组织规律的有效工具,在揭示城市有机体复杂演化机制方面发挥重要作用。目前分形城市研究以指标构建和实证分析为主,缺乏系统的梳理和回顾;内容上侧重几何分形,复杂城市网络视角下的结构分形研究薄弱。本文简要回顾了近30余年来分形城市研究的发展历程,梳理了分形城市研究脉络:从城市形态的几何分形到城市结构与关联的网络分形,从静态分形特征到动态异速生长,并展望了分形城市未来研究方向。

关键词：分形城市形态城市网络几何分形网络分形分形维异速生长

3D Numerical Simulation Analysis of Passive Drag near Free Surface in Swimming

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china Ocean engineering 2015年第2期29卷 265-273页

作者：詹杰民李天赠陈学彬李毓湘韦永康 department of Applied Mechanics and engineering Sun Yat-sen University department of civil and Environmental {2. The Hong Kong Polytechnic University

The aim of this work is to build a 3D numerical model to study the characteristics of passive drag on competitive swimmers taking into account the impact of the free surface. This model solves the 3D incompressible Navier-Stokes equations using RNG k-ε turbulence closure. The volume of fluid（VOF） method is used to locate the free surface. The 3D virtual model is created by Computer Aided Industrial Design（CAID） software, Rhinoceros. Firstly, a specific posture of swimming is studied. The simulation results are in good agreement with the data from mannequin towing experiments. The effects of a swimmer＇s arms and legs positions on swimming performance are then studied. Finally, it is demonstrated that the present method is capable of simulating gliding near the free surface.

关键词： swimming passive drag VOF method numerical simulation