Managing transportation during highway reconstruction: A recommended process

Major highway reconstruction can cause significant disruptions to existing travel patterns and economic activity. Reducing these impacts on travelers, shippers, businesses and residents requires that innovative and effective transportation management actions be developed and implemented. This paper reports the major findings and recommendations of a research study on managing transportation during highway, reconstruction. The primary objectives of the study were

乙二醇机组的温度模糊控制器设计与仿真

针对我国通信行业和计算机行业大型机房耗电量大的现状,提出了一种乙二醇机组控制系统。介绍了它的工作原理,阐述了它的总体控制方案,并重点阐述了采用温度模糊PID控制器对室内温度进行调节。仿真和实验结果表明：采用温度模糊控制器的系统运行稳定、可靠性高、节能效果明显,具有广阔的应用前景。     

野三关隧道DK 124+602突水相关水文地质分析

研究目的:野三关隧道出口突发性大涌水,造成灾害。研究与分析施工资料、既有水文地质资料及现场观测资料,探究其原因,总结其规律,有效地确定其设计、施工整治方案,规避施工风险。研究结论:志留系碎屑岩组成的山地分水岭与栖霞组、茅口组灰岩组成的山地斜坡之间的地貌交界处和岩性界面处是汇水富集的地方;P1q+m富水地层中发育3#暗河,存在3个不同类型的充水层,它们都与3#暗河有不同程度的联系,隧道突水将暗河导入隧道;改道后的暗河继承、保留了原3#暗河的管道流特征、径流流量动态变化特征、降雨-流量关系特征等;暗河改道将对环境产生一定影响、大流量水流突出的泥石和随带的泥沙对施工和营运养护将造成困难。     

铁路建设项目环境影响后评价指标体系初步研究

在目前国内外研究现状的基础上,结合铁路建设项目的特点,初步建立了以生态环境、噪声与振动环境、电磁环境、水环境、大气环境、固体废弃物和社会环境等7个互为关联和补充环境因子构成的铁路建设项目环境影响后评价指标体系,并利用构建的指标体系对成都至都江堰铁路环境影响后评价进行了分析。     

工程车辆FOPS冲击试验中落锤塑性变形研究

为了对工程车辆的落物保护装置(FOPS)进行可靠性试验提供理论依据,采用冲击动力学的塑性波两侧的动量平衡理论对工程车辆FOPS受冲击时落锤的动态响应进行了研究,建立了锤头变形的基本方程,绘制了方程相应曲线;建立了锤头在冲击过程中任一瞬时变形长度和非变形长度的数学模型,找到了工程应变和冲击速度之间的曲线对于塑性大变形的突变点及影响落锤变形的各个因素和控制变形的依据。为减小落锤的蘑菇形尺寸,降低锤头的材料成本,多次重复使用落锤,进行合理的落锤结构设计指明了方向。     

An Exploration of the Relationship between Timing and Duration of Maintenance Activities

The timing and duration of an activity episode are two important temporal aspects of activity-travel behavior. Understanding the causal relationship between these two variables would be useful in the development of activity-based travel demand modeling systems. This paper investigates the relationship between these two variables by considering two different causal structures – one structure in which time-of-day choice is determined first and influences duration and a second structure in which activity duration is determined first and affects time-of-day choice. These two structures are estimated within a discrete-continuous simultaneous equations framework employing a full-information maximum likelihood methodology that allows error covariance. The estimation is performed separately for commuter and non-commuter samples drawn from a 1996 household travel survey data set from the Tampa Bay area in Florida. The results of the model estimation effort show that the causal structure in which activity duration precedes or affects activity timing (time of day choice) performs better for the non-commuter sample. For the commuter sample, the findings were less conclusive with both causal structures offering equally good statistical measures of fit. In addition, for the commuter sample, all error correlations were found to be zero. These two findings suggest that time of day choice and activity episode duration are only loosely related for the commuter sample, possibly due to the relatively non-discretionary and inflexible work activity and travel.     

汽车侧翻和滚翻事故建模研究

分析汽车在侧翻和滚翻过程中的受力状态和轮胎或车身与路面的相互作用方式,建立汽车侧翻和滚翻的运动学和动力学模型,揭示汽车临界侧翻碰撞力与持续作用时间等参数的关系,推导侧翻车辆侧向速度的范围,确定滚筒模型中关键参数的选取方法。事故案例表明模型在实际应用中效果良好、定量准确、直观性强。     

快速公交专用车道及站台布设模式选择

专用车道和站台是快速公交系统（BRT）重要的设施要素,对其布设模式进行了研究。从3种典型的布设模式入手,即中央专用车道＋岛式站台、中央专用车道＋侧式站台、路侧专用车道＋侧式站台,分析其规划设计要点、模式优缺点、适用性等。总结快速公交系统规划过程中影响专用车道及站台布设模式选择的因素,包括BRT在城市中的功能定位、道路条件、交通量等方面。以南宁市快速公交线网规划中专用车道及站台的规划设计为例,对其布设模式选择、专用车道及站台的布设进行分析。     

重质液货晃荡载荷作用下薄膜型VLEC液货围护系统响应研究

随着美国页岩气中乙烷的大量出口,VLEC(超大型乙烷运输船)将成为新造船市场的热点,而薄膜型液货围护系统(CCS)的超大型乙烷运输船(VLEC)应该是大势所趋。高密度货物和大尺寸液舱造成了液货静压力和晃荡冲击压力的增加,提出了新的问题,VLEC液货围护系统的强度能否抵抗增加的晃荡冲击载荷。本文首先利用非线性有限元法计算分析液货围护系统在不同边界条件下的极限强度。然后运用CFD分析法对液舱晃荡问题进行数值分析,确定危险晃荡区域和晃荡载荷。最后对液货围护系统在液舱晃荡分析确定的危险工况进行响应分析,验证了围护系统的可靠性并归纳了一些重要结论。     

铁路噪声预测计算方法

根据声学基本理论和有关有限长运动线声源指向性、等效时间等声学特性研究成果,结合铁路噪声的特点,总结了比例法和模式法两种主要的噪声预测方法,并给出了相应的计算公式,可供铁路建设项目环境影响评价中预测铁路噪声时参考。