替代燃料的燃料消耗量计算方法

文章介绍了碳平衡原理的两个方面,燃烧和稀释前后的碳质量不变。介绍了完全燃烧后的CO2理论浓度和稀释倍数以及用稀释倍数校正稀释排气的方法,介绍了由碳质量分数推导替代燃料碳质量分数和当量分子式的方法,最后推导得出了可用于替代燃料的燃料消耗量计算公式。     

浅析内河航道节能现状及技术应用

内河航道在施工建设和运营管理期间会产生大量的能源消耗,抓好航道的节能减排对发展绿色交通具有重要作用。本文总结概况了目前我国内河航道节能减排现状及采用的关键技术,相关技术的推广将引导交通运输行业优化用能结构、促进产业协调发展。     

车用柴油机NO_x形成及控制

相对汽油发动机污染物排放,柴油发动机CO和CH的排放较低,不到汽油机的10%,但NOX排放水平却高于汽油发动机。本文重点讨论柴油发动机排气污染物中NOx的成分及危害,分析了NO的生成机理及影响因素,提出了控制柴油机NO排放的技术和方法。     

Development and calibration of a long-distance passenger traffic assignment model

This paper studies the assignment of long-distance passenger traffic on a highway corridor network. First, we propose a traditional model for the long-distance traffic assignment considering interactions with local commuter traffic. It addresses the effect of local networks on highway corridors. An iterative algorithm is developed to solve for the exact solution. Then, to address the potential computational issues that arise therein, a decomposition method is proposed by introducing a new concept of corridor elasticity. An assignment procedure for long-distance passenger traffic is developed accordingly. Numerical tests show that the proposed decomposition method makes significant improvements in computational performance at a small loss of optimality. This decomposition method well approximates the exact assignment from the traditional formulation, especially when the highway corridors are near-saturation. The proposed decomposition method appears practical for application.     

熊洞湾隧道出口平导涌水处理探讨

在熊洞湾隧道工程中,针对在平行导洞实施超前地质钻探时出现的涌水现象,通过采取地形地貌考察、TSP超前地质预报、红外探水、超前地质钻探以及水质检验等措施,最终确定了该出水点水源性质及处理方案.文章介绍了工程背景和地质特征,对涌水的原因,以及采取的处理方案和技术措施进行了分析研究.     

基于灰色理论的隧道围岩收敛预测

文章根据隧道围岩收敛监测信息,应用灰色系统原理和方法,建立了GM(1,1)模型并进行了预测。预测结果表明,灰色模型预测值与实测值吻合程度较好,能为隧道的动态设计和信息化施工提供决策依据。     

硅油型制动液的研究及应用进展

硅油型制动液性能优异,能显著延长制动液更换周期,减少车辆维护成本。本文综述了国外硅油型制动液的研制进展、产品组成、美军产品规范MIL-PRF-46176B和SAEJ1705标准,以及硅油型制动液在车辆上的应用情况。     

Do parking requirements significantly increase the area dedicated to parking? A test of the effect of parking requirements values in Los Angeles County

Minimum parking requirements (MPRs) are the norm for urban and suburban development in the United States (Davidson et al., 2002). The justification for MPRs is that overflow parking will occupy nearby street or off-street parking. Shoup (1999a) and Willson (1995) provide cases where there is reason to believe that parking space requirements have forced parcel developers to place more parking than they would in the absence of parking requirements. However, to our knowledge the existing literature does not test the effect of parking minimums on the amount of lot space devoted to parking beyond a few case studies. This paper tests the hypothesis that MPRs bind for most land uses using data on suburban office, commercial, industrial and retail property sales from Los Angeles County using both direct and indirect approaches. Our indirect test of the effects of parking requirements is similar to the one used by Glaeser and Gyourko (2003). A simple theoretical model shows that the marginal value of additional parking to the sale price of a building should be equal to the cost of land plus the cost of parking construction. We estimate the marginal values of parking and lot area with spatial methods using a large data set from the Los Angeles area non-residential property sales and find that for most of the property types the marginal value of parking is significantly below that of the parcel area. In addition, we directly examine required and supplied parking and find that on average parking supplied is quite close to the required amount.     

我国汽车环保检测业的发展现状与出路

在汽车行业快速发展的今天,汽车环保检测业作为汽车市场的服务行业,也逐步发展起来。本文首先阐述了我国汽车环保检测业的发展现状,重点分析了行业存在的问题,最后提出了行业发展的对策。     

船舶燃油系统使用低硫油的应对新措施

随着全球环境保护需求的不断提高,使得有关船舶硫化物排放的国际标准日益严格,从而导致船用低硫柴油的应用量正在逐渐增加。然而,目前大多数柴油机和燃油系统是针对传统燃油而设计的,由于低硫油的特殊性质,在使用低硫燃油过程中必然会产生一些问题。本文就低硫油的性质总结出了最新应对措施,确保了船舶的安全营运。