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291.
基于美国气垫登陆艇(LCAC)的研制实情及其最近的延寿计划(SLEP)和其未来替代者——舰岸连接器(SSC)的发展趋势,对LCAC的快速性等总体性能进行计算和分析,并追踪LCAC有关新技术在芬兰T-2000艇与韩国LSF-II艇上的应用情况。 相似文献
292.
This study attempts to present an urban road transportation strategy focusing on the mitigation of both GHGs emission and public health damage, taking Xiamen City as a case study. We developed a Public Health and GHGs Emission model to estimate the impacts of direct energy-consumption-related GHGs emissions and public health damage in Xiamen’s road transportation strategies from 2008 to 2025, considering the environmental benefits and economic costs. Two scenarios were designed to describe future transportation strategies for Xiamen City, and mitigation potentials for both GHGs emission and public health costs were estimated from 2008 to 2025 under a series of options. The results show that enacting controls on private vehicles would be most effective to GHGs mitigation, while enacting controls on government and rental vehicles would contribute the most to NO2 and PM2.5 reductions. Compared with the Business as Usual scenario, the Integrated scenario would achieve about a 68% energy consumption reduction and save 0.23 billion yuan (95% CI: 0.16, 0.32) in health costs in 2025. It is clear that integrated and advisable strategies need to mitigate the adverse impacts of urban road vehicles on GHGs emissions and public health and economic costs, particularly in regions of rapid urbanization. 相似文献
293.
As goods movement continues to increase it is expected to outpace infrastructure capacity in the United States. Moving a larger share of goods by rail rather than truck is a potentially cost effective part of a solution. Freight rail not only offers a substitute for truck trips but is a cleaner, more energy efficient, and safer alternative. Recently a number of private freight rail projects have received public funding. The public funds are aimed at increasing freight rail capacity with the goal of diverting some goods currently moved by truck to rail. While the benefits of moving goods by rail are relatively clear, it is unclear if public decision makers can effectively identify strategic rail investments that will achieve their policy goals. This study critically examines the analytical methods, models, and data that are commonly used to support decisions to provide public funds for private freight rail projects. This is accomplished through a case study of California’s Trade Corridors Improvement Fund program which provided $680 million for 11 freight rail projects. The study’s contributions include identifying critical analytical flaws and challenges affecting the benefit estimates that public funding decisions rely on. Improvements to current evaluation methods are also identified as are regulatory reforms and policy interventions that may offer more effective and reliable outcomes. 相似文献
294.
陶金忠 《南通航运职业技术学院学报》2005,4(4):43-46
文章阐述了汽车空气悬架的结构类型和工作原理,汽车空气悬架的特性(可变刚度、低固有频率、准等频特性),汽车空气悬架的优缺点以及汽车空气悬架的发展趋势. 相似文献
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为寻求真正理想的现代船舶舱室空气调节再生技术,对特种氧化物法、氧烛法、高压氧瓶法、电解水法等现有技术的原理及应用情况进行了简要介绍,在此基础上进一步综合分析了这些技术均无法满足空气清新度的要求,而且还存在其它各自固有的一些问题。为此,创造性地提出了基于特定海洋生物的船舶舱室空气再生的新思想,已取得的初步研究成果表明它既能保证舱室内O2和CO2的合适浓度,又能保证整个舱室环境空气的清新度,还可望带来其它一些明显优势,体现了潜在的重大现实意义。 相似文献
298.
骨架密实型沥青混合料设计 总被引:6,自引:0,他引:6
提出一种新的基于计算的设计方法,按照新规范关键筛孔的定义,将粗集料分3档进行二级填充的干捣实试验,确定最佳骨架。油石比确定参照林绣贤教授的油石比计算法。假定细料、矿粉、沥青形成的胶浆完全填充入骨架间隙中,确定设计空隙率,选择适宜的粉胶比,结合具体矿料的筛分结果,直接计算得最佳骨架密实型沥青混合料的级配。试验结果表明,该设计方法简单易行,所得级配经济合理、且各项性能符合技术要求。 相似文献
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分析大粒径AM基层的特点、材料技术指标及性能。通过大型马歇尔试套,确定AM基层材料配合比,提出应通过对AM混合料进行车辙试验、浸水马歇尔试验、冻融劈裂试验来确定路基性能。 相似文献