oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
The Choice of AC Electricity Bridge Adjustment Parameters  [cached]
Zaiqi Fu,Changji Shan,Yuhui Luo,Xungang Yang
Modern Applied Science , 2009, DOI: 10.5539/mas.v2n6p143
Abstract: It is set forth that how to choose adjustment parameters in the plural plane coordinate figure by the relation of Electricity Bridge’s balance condition and adjustment parameters.
Delay Adjustment Method at Transfer Station of High-Speed Railway  [PDF]
Li Xiaojuan,Han Baoming,Zhang Qi
Advances in Mechanical Engineering , 2013, DOI: 10.1155/2013/752632
Abstract: Passenger transfer is one of the important research contents after the network operation of high-speed railway. Due to the high operation speed and high frequency, delays at transfer stations may occur frequently, leading to some potential safety problems. Main influence factors such as schedule time, transfer buffer time, waiting time, and delay time of delay and passengers classification during transfer were analyzed. A delay adjustment model of passengers at a transfer station was presented with minimal delay cost, waiting time cost, and adjustment cost as the optimization goal. Two adjustment strategies were proposed, including transfer passengers departure time adjustment and connecting trains departure time adjustment. And a delay adjustment algorithm at transfer station was designed for the optimal adjustment scheme. A case study proves the effectiveness of the method on optimal scheme design for passengers transfer based on the lowest delay cost of all passengers. 1. Introduction For the high-speed railway network, it is impossible to operate direct train between two stations, especially between the long distance lines and feeder lines. So the passenger transfer is an important research problem of transportation organization. The passenger delays will not only easily lead to safety problems and affect the normal transportation, but also cause the negative effects on society. So an effective delay adjustment method is very critical both for passengers and railway operators. In the past, much research has been dedicated to compute optimum railway timetables to research the train delays and reliability of timetables. Su and Nigel [1] mainly analyzed the frequent minor disruptions (usually last no longer than 10–20 minutes) caused by random disturbances. And they described an integrated real-time disruption control model for a single line on rail transit systems, which includes holding, expressing, and short-turning strategies. Vromans et al. [2] examined reliability in public railway systems. And they decreased the interdependencies between trains by reducing the running time differences per track section and by this creating more homogeneity of a timetable. Huisman et al. [3] discussed some recently developed topics such as shunting and reliability of timetables. And then many studies with a view to optimize timetable synchronization for rail transit and transfer optimization problem [4–7]. They researched the transfer optimization problem by minimizing the passenger transfer time or transfer waiting time of the public transport. Then, many
Structural Deformation Monitoring and Analysis of Highway Bridge Using Accurate Geodetic Techniques  [PDF]
Ashraf Abd El-Wanis Beshr
Engineering (ENG) , 2015, DOI: 10.4236/eng.2015.78045
Abstract: As the new materials and technologies are increasingly applied to construction of civil infrastructures such bridges, dam and tunnels, the need for structural monitoring systems, maintenance and restoration becomes more important and vital. Bridges are widespread in every society and affect its human, social, economical and cultural aspects. Measurements and monitoring of the structural deformation of highway bridges have an essential role in structural safety. This paper investigates an integrated monitoring system for estimation of the deformation behavior of one of the important reinforced bridges in Egypt. The applied data for analysing the deformation of any structure from geodetic observations are the coordinates of several monitoring points distributed on the structure itself. The coordinates of these points are calculated with respect to control fixed points. So any deviations in the control points coordinates between the two successive epochs of observations will affect the values of structural deformation. To overcome this shortage, applying the multi-parameter transformation will be studied in this paper for structural health monitoring of bridges. Statistical tests using F-Fisher criterion with a confidence level of 98% of the geodetic observations for bridge deformation values are also presented. The results of the practical measurements, analysis of the interesting deformation technique and traffic flow around the studied highway bridge are also presented. The resulting structural deformation values from statistical tests provide a significant improvement of understanding and prediction the structure deformation values of highway bridges.
盾构下穿铁路桥涵变形规律及控制技术研究
Rules and control technology of deformation caused by shield tunnel under-passing the railway bridge culvert
 [PDF]

王国富,王建,路林海
WANG Guofu
,WANG Jian,LU Linhai

- , 2016,
Abstract: 以济南轨道交通R1线玉符河站~王府庄站区间盾构隧道下穿京沪铁路框架桥涵为背景,采用FLAC3D软件进行数值模拟,分析下穿施工中桥涵结构应力变形和铁路轨道变形特征。结果表明:下穿过程中桥涵最大压应力位于盾构左线上方立柱,其值为5.06 MPa,最大拉应力位于桥涵右侧顶部,其值为1.00 MPa;穿越过程桥涵最大沉降值达到5.81 mm,均满足结构应力、变形控制标准;由桥涵上方各轨道的最终变形曲线与左、右线拱顶上方轨道的变形时程曲线得出靠近施工侧轨道先于其他轨道产生沉降,最终沉降值随开挖方向依次增大至3.76 mm。结合分析结果提出盾构下穿铁路桥涵施工控制技术及监测控制方案,确定了盾构下穿施工20 m范围为重点监测区,并提出适用于济南轨道交通建设的沉降控制标准。
In the engineering background of the Jinan rail transit line R1 line Yufu River Station ~Wangfu-zhuang station shield tunnel under-passing the Beijing-Shanghai railway frame bridge. With the help of FLAC3D,the deformation and stress of the bridge structure is simulated numerically and the characteristics of railway track deformation are analyzed. The calculation results show that the maximum compressive stress of bridge is 5.06 MPa in the position of the column above the left line of the shield at the process of under-passing bridge, and the maximum tensile stress of bridge is 1.00 MPa at the top of the bridge culvert right side; sedimentation value of the bridge culvert through the process reached 5.81 mm. These results all meet the stress and deformation control standards. Based on the final deformation curves of track structure above bridge culvert and deformation time history curves of track at the top of the left and right lines. It is concludecl that the rail track close to construction side get settlement before the other tracks, the final settlement value increases with the excavation direction to 3.76 mm. Combined with the results of the analysis,construction control technologies and monitoring and control schemes are proposed for the shield tunnel under-passing the railway bridge culvert. The scope of 20 m is determined as the key monitoring area and settlement control standards for the construction of Jinan rail transit are presented
Analytical Research on Deformation Monitoring of Large Span Continuous Rigid Frame Bridge during Operation  [PDF]
Aicheng Shan
Engineering (ENG) , 2015, DOI: 10.4236/eng.2015.78044
Abstract: Based on a large span continuous rigid frame bridge in Chongqing of China, the main pier vertical displacement and deviation, the bridge deck alignment and the expansion joint deformation are analytically researched during operation. Firstly, the monitoring content and method of the large span continuous rigid frame bridge are clearly stated. Secondly, by finite element software Midas Civil, the relevant deformation values of the bridge are calculated. Thirdly, in practice, the relevant deformation values of the bridge are measured. Finally, the measured values in practice are compared with the calculated ones by the finite element software Midas Civil, finding that the former is less than the latter, and it can be concluded that the bridge is basically in the normal working condition. In this paper, the analytical research on the deformation monitoring can provide the basis for similar bridges, which has good practical significance.
An Auto-Adjustment Video Mechanism for Steadily Monitoring of Remote Laboratory  [cached]
Jian-Wei Lin
International Journal of Online Engineering (iJOE) , 2009, DOI: 10.3991/ijoe.v5i4.977
Abstract: This work presents an auto-adaptable video streaming Web-based system, enabling on-line simultaneously monitoring of multiple instruments of remote experiment. The system is capability of not only handling multiple concurrent stream processes, but also automatically tuning encoding parameters of the running video streaming processes once overload so that the whole system can always keep in a smooth and steady circumstance.
Liquid bridge pinch off and satelite drop formation under thermocapillary effect in Japanese Experiment Module 'Kibo' aboard the International Space Station  [PDF]
Ichiro Ueno,Koichi Nishino,Mitsuru Ohnishi,Hiroshi Kawamura,Masato Sakurai,Satoshi Matsumoto
Physics , 2012,
Abstract: The long-duration fluid physics experiments on a thermocapillary-driven flow have been carried out on the Japanese experiment module 'Kibo' aboard the International Space Station (ISS) since 2008. In these experiments, various aspects of thermocapillary convection in a half-zone (HZ) liquid bridge of high Prandtl number fluid have been examined under the advantages of the long-duration high-quality microgravity environment. This fluid dynamics video introduce a pinch off of liquid bridge of 30 mm in diameter as a part of the on-orbit experiments. The effect of thermocapillary-driven flow on the pinch off and satellite drop formation is examined.
PARAMETER SENSITIVITY ANALYSIS OF THE EFFECT OF LONGITUDINAL RESTRAINT LENGTH OF OLD STATION ON DEEP PIT DEFORMATION OF TRANSFER METRO STATION
老车站纵向约束长度对换乘站基坑变形影响的敏感性分析

Yao Yanming,Sun Wei,Chen Xulu,Zhou Shunhua,
姚燕明
,孙巍,陈绪禄,周顺华

岩石力学与工程学报 , 2004,
Abstract: Due to the space restraint,new parallel transfer metro station will be built close to the old station. The divisional walls will divide the long strip pit into several small pits that will be excavated alternately to keep the old station stable and safe during deep pit excavation. The longitudinal length of the old station is several hundred meters and the nearby excavation range in the divisional walls is tens of meters,so the station deformation in the excavation is restrained by its two side longitudinal station structure. When the pit is analyzed by three-dimensional shell finite element,the longitudinal restraint length of old station is changed. The parameter sensitivity analysis is made on the effect and the reference value is proposed.
SEMIPARAMETRIC COMPENSATION METHOD FOR MODEL ERROR OF DEFORMATION ADJUSTMENT SYSTEM
变形平差系统模型误差的半参数补偿方法

Gao Ning,Cui Ximin,Gao Caiyun,Wang Guo,Zhao Wandong,
高宁
,崔希民,高彩云,王果,赵万东

大地测量与地球动力学 , 2012,
Abstract: In deformation data processing,due to various approximations existing in the process of building model,it is inevitable that the model errors exist in the adjustment system.We discusses some theoretical problems affecting parameters estimation,proposes that model error can be solved with semiparametric penalized least squares and discusses the choice of regular matrix R and smoothing parameter α affecting the forecasted results.Finally,an adjustment problem in dam safety monitoring is used to test the method and the semiparametric model,autoregressive model,grey model and grey wavelet analysis method are compared with each other.The results demostrate that the model errors can be compensated correctly by semiparemetric method.
Exposure of Petrol Station Attendants and Auto Mechanics to Premium Motor Sprit Fumes in Calabar, Nigeria  [PDF]
N. E. Udonwa,E. K. Uko,B. M. Ikpeme,I. A. Ibanga,B. O. Okon
Journal of Environmental and Public Health , 2009, DOI: 10.1155/2009/281876
Abstract: A population-based-cross-sectional survey was carried out to investigate the potential risk of exposure to premium motor spirit (PMS) fumes in Calabar, Nigeria, among Automobile Mechanics (AM), Petrol Station Attendants (PSA) and the general population. Structured questionnaire was administered on the randomly chosen subjects to elicit information on their exposure to PMS. Duration of exposure was taken as the length of work in their various occupations. Venous blood was taken for methaemoglobin (MetHb) and packed cells volume (PCV). Mean MetHb value was higher in AM (7.3%) and PSA (5.8%) than in the subjects from the general population (2.7%). PCV was lower in PSA (30.8%), than AM (33.3%) and the subjects from the general population (40.8%). MetHb level was directly proportional, and PCV inversely related, to the duration of exposure. The study suggested increased exposure to petrol fumes among AM, PSA, and MetHb as a useful biomarker in determining the level of exposure to benzene in petrol vapour.
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.