公路建设环境影响评价软件分析及开发新思路

为提高公路建设环境影响评价软件系统的实用性和精确度,通过对目前常用的环境影响评价软件如Sound-PLAN、EIAA、EIAW和、RoadEIA进行分析,提出了它们在用于公路建设环境影响评价时的特点。并在此基础上,结合调研工作提出了开发公路建设环境影响评价系统的新思路,为进一步开发系统提供了现实和理论依据。     

冻融作用下水分迁移对压实黄土强度影响的宏微观试验研究

在季节性冻土区,冻融作用下土体的水分迁移及其伴生现象会诱发黄土路基发生病害,探明冻融作用下水分迁移对压实黄土强度的影响及其机制,对于黄土地区路基工程冻融病害防治非常必要.采用大尺寸设备对洛川黄土开展单向冻结-双向融化作用下的冻融循环试验,对土体温度场、水分场均加以监测,并在此基础上进行直剪试验和电镜扫描试验.结果表明:...     

高速铁路弓网检测监测体系研究

良好的弓网关系是保障列车高速安全运行的基础,为确保弓网系统长期服役的可靠性,有必要建立高速铁路弓网检测监测体系.在梳理高速铁路弓网系统检测监测需求的基础上,吸收供电6C系统成果,构建高速铁路弓网检测监测体系框架,从感知、传输、数据、分析和应用5个层面进行分析描述,论述弓网检测监测系统的关键技术与实现方法,阐述体系在弓网...     

汽车按钮式开关寿命试验装置的研制

利用汽车雨刮器电机为动力,设计制造了一种低成本的汽车按钮式开关寿命试验装置。该装置有合理的调整点和润滑措施,在汽车按钮式和翘板式开关寿命试验中,调整方便,能进行可靠性的测试评价。     

轿车底盘零部件耐久性虚拟试验方法研究

针对轿车开发过程中传统耐久性试验周期长费用高的缺点,以实车道路载荷谱采集试验为基础,应用多体系统动力学(MBS)和有限元(FEA)仿真技术建立整车的虚拟仿真模型,通过耐久性虚拟试验实现整车开发过程中底盘零部件疲劳寿命的有效预估。将疲劳寿命的仿真值与试验值进行对比分析,结果表明两者具有较高的一致性,说明耐久性虚拟试验可以有效地实现关键零部件的疲劳寿命预测。     

生命周期评价及其在汽车排放领域的应用

介绍了生命周期评价(LCA)的定义、评估对象、范围、评价思路、步骤及其体系框架,说明了汽车排放分析中存在的两种循环(燃料循环和车辆循环)。通过分析汽车生命周期排放模型及其在CATCH(Clean A ccessible Transport for Community Health)研究中的一个实际应用案例,进一步阐明了生命周期评价在对各种燃料进行排放分析过程中的实际应用价值,最后介绍了生命周期评价在国外汽车企业中的研究发展情况、实际产品以及应用前景。     

Development and Theoretic Validation of Model of Drum Level Sloshing

In order to develop a feasible model of drum level sloshing, the mechanism of drum level sloshing was analyzed, and the model of drum level sloshing was developed on the Easy5 software flat. The thermodynamic property of the model was validated by using the reference model, which was set up by using the method of lump parameter. The results indicate that the model can precisely reflect the phenomena of thermodynamic property inside drum, and the numeric error is within 1%. And the hydraulic property of the model was validated by the analytical theory of liquid sloshing, and the results indicate that the hydraulic property inside drum can also be correctly reflected by the model, and the sloshing period error is within 5%. The important work was done for exploring modeling for drum level sloshing, research of drum level sloshing and precision controlling of drum level.     

Modal analysis of real-time,real world vehicular exhaust emissions under heterogeneous traffic conditions

This study presents the characteristics of real world, real time, on-road vehicular exhaust emission namely, carbon monoxide (CO), nitric oxide (NO), hydrocarbons (HC), and carbon dioxide (CO₂) emitted under heterogeneous traffic conditions. Field experiments were performed on major category of vehicles in developing countries, i.e. two-wheelers, auto-rickshaws, cars and buses. The on-board monitoring was carried out on different corridors with varying road geometry. Results revealed that the driving cycle was dependent on the road geometry, with two lane mixed flow corridor having lot of short term events compared to that of arterial road. Vehicular emissions during idling and cruising were generally low compared to emissions during acceleration. It was also found that emissions were significantly dependent on short term events such as rapid acceleration and braking during a trip. Also, the standard emission models like COPERT and CMEM under predicted the real world emissions by 30–200% depending upon different driving modes. The on-road emissions measurements were able to capture the emission characteristics during the micro events of real world driving scenarios which were not represented by standard vehicle emission measured at laboratory conditions.     

A Value-at-Risk (VAR) approach to routing rail hazmat shipments

Hazardous materials (hazmat) accidents are rare though the consequences could be disastrous. Given the possibility of low probability – high consequence event, a risk-averse routing hazmat shipment is necessary. We propose a value-at-risk (VaR) approach to route rail hazmat shipments, using the best train configuration, over a given railroad network with limited number of train services such that the transport risk as measured by VaR is minimized. Freight train derailment reports of the Federal Railroad Administration were analyzed to develop expressions that would incorporate characteristics of railroad accidents, and then to estimate the different inputs. The proposed methodology was used to study several problem instances generated using the realistic network of a railroad operator, and to demonstrate that it is possible to develop different routes for shipments depending on the risk preference of the decision maker.