A cradle-to-grave life cycle assessment is done to identify the environmental impacts of chromated copper arsenate (CCA)-treated timber used for highway guard rail posts, to understand the processes that contribute to...A cradle-to-grave life cycle assessment is done to identify the environmental impacts of chromated copper arsenate (CCA)-treated timber used for highway guard rail posts, to understand the processes that contribute to the total impacts, and to determine how the impacts compare to the primary alternative product, galvanized steel posts. Guard rail posts are the supporting structures for highway guard rails. Transportation engineers, as well as public and regulatory interests, have increasing need to understand the environmental implications of guard rail post selection, in addition to factors such as costs and service performance. This study uses a life cycle inventory (LCI) to catalogue the input and output data from guard rail post manufacture, service life, and disposition, and a life cycle impact assessment (LCIA) to assess anthropogenic and net greenhouse gas (GHG), acidification, smog, ecotoxicity, and eutrophication potentially resulting from life cycle air emissions. Other indicators of interest also are tracked, such as fossil fuel and water use. Comparisons of guard rail post products are made at a functional unit of one post per year of service. This life cycle assessment (LCA) finds that the manufacture, use, and disposition of CCA-treated wood guard rails offers lower fossil fuel use and lower anthropogenic and net GHG emissions, acidification, smog potential, and ecotoxicity environmental impacts than impact indicator values for galvanized steel posts. Water use and eutrophication impact indicator values for CCA-treated guard rail posts are greater than impact indicator values for galvanized steel guard rail posts.展开更多
开发标准轨距54E1钢轨9号单开道岔,是为了开拓海外市场、通过欧盟铁路互联互通技术规范(Technical Specification for Interoperability,TSI)认证而研制的满足欧洲标准(European Norms,EN)的道岔产品。介绍该道岔产品的设计参数和结构特...开发标准轨距54E1钢轨9号单开道岔,是为了开拓海外市场、通过欧盟铁路互联互通技术规范(Technical Specification for Interoperability,TSI)认证而研制的满足欧洲标准(European Norms,EN)的道岔产品。介绍该道岔产品的设计参数和结构特点,检算道岔的安全参数、尖轨转换参数,并验证岔枕强度。该道岔的转辙器采用弹性可弯尖轨,尖轨跟端设置限位器结构,基本轨内侧采用弹性夹弹性扣压,设置辊轮滑床板以减少尖轨转换阻力;辙叉采用焊接式高锰钢整铸辙叉,护轨选用33 kg·m^(-1)的槽型护轨,护轨垫板处基本轨内侧采用弹性夹弹性扣压。展开更多
为了进一步系统地研究新型护轨在小半径曲线段的减振、防磨效果,考虑新型护轨结构特点及其与车轮、钢轨之间相互作用,建立曲线段轮轨接触模型,并分析其受力特性。以某地铁小半径曲线安装护轨段为研究基础,对安装新型护轨和没有安装护轨...为了进一步系统地研究新型护轨在小半径曲线段的减振、防磨效果,考虑新型护轨结构特点及其与车轮、钢轨之间相互作用,建立曲线段轮轨接触模型,并分析其受力特性。以某地铁小半径曲线安装护轨段为研究基础,对安装新型护轨和没有安装护轨的近似线路进行不同速度的在线测试、锤击试验及波磨测试,通过对比试验得到:安装有护轨的线路,钢轨的垂向振动加速度级降低了2.2 d B、横向振动减小了3.1 d B。当列车速度从40 km/h提高到55 km/h,有/无护轨的钢轨振动加速度级都逐渐增大,但有护轨的横向振动可降低3.4 d B;有护轨线路的在波长约50mm的波磨明显减低。新型护轨减振效果通过轨道不连续支撑特征频率理论得到进一步验证。理论分析和测试结果表明,安装新型防脱护轨在抑制钢轨振动和减缓钢轨波磨增长等方面起到很好的效果。展开更多
文摘A cradle-to-grave life cycle assessment is done to identify the environmental impacts of chromated copper arsenate (CCA)-treated timber used for highway guard rail posts, to understand the processes that contribute to the total impacts, and to determine how the impacts compare to the primary alternative product, galvanized steel posts. Guard rail posts are the supporting structures for highway guard rails. Transportation engineers, as well as public and regulatory interests, have increasing need to understand the environmental implications of guard rail post selection, in addition to factors such as costs and service performance. This study uses a life cycle inventory (LCI) to catalogue the input and output data from guard rail post manufacture, service life, and disposition, and a life cycle impact assessment (LCIA) to assess anthropogenic and net greenhouse gas (GHG), acidification, smog, ecotoxicity, and eutrophication potentially resulting from life cycle air emissions. Other indicators of interest also are tracked, such as fossil fuel and water use. Comparisons of guard rail post products are made at a functional unit of one post per year of service. This life cycle assessment (LCA) finds that the manufacture, use, and disposition of CCA-treated wood guard rails offers lower fossil fuel use and lower anthropogenic and net GHG emissions, acidification, smog potential, and ecotoxicity environmental impacts than impact indicator values for galvanized steel posts. Water use and eutrophication impact indicator values for CCA-treated guard rail posts are greater than impact indicator values for galvanized steel guard rail posts.
文摘为了进一步系统地研究新型护轨在小半径曲线段的减振、防磨效果,考虑新型护轨结构特点及其与车轮、钢轨之间相互作用,建立曲线段轮轨接触模型,并分析其受力特性。以某地铁小半径曲线安装护轨段为研究基础,对安装新型护轨和没有安装护轨的近似线路进行不同速度的在线测试、锤击试验及波磨测试,通过对比试验得到:安装有护轨的线路,钢轨的垂向振动加速度级降低了2.2 d B、横向振动减小了3.1 d B。当列车速度从40 km/h提高到55 km/h,有/无护轨的钢轨振动加速度级都逐渐增大,但有护轨的横向振动可降低3.4 d B;有护轨线路的在波长约50mm的波磨明显减低。新型护轨减振效果通过轨道不连续支撑特征频率理论得到进一步验证。理论分析和测试结果表明,安装新型防脱护轨在抑制钢轨振动和减缓钢轨波磨增长等方面起到很好的效果。
