Rural environment stakeholders and policy making: Willingness to pay to reduce road transportation pollution impact in the Western Pyrenees

In spite of the strategic national and regional development importance of transportation infrastructures, road transportation is one of the major sources of externalities worldwide. Using data collected from 900 residents living in 14 rural towns near the roads crossing the Spanish Pyrenees, we model citizens’ willingness-to-pay (WTP) to reduce noise and air pollution. We collect the data adopting a contingent valuation method (CVM) design and we analyze the data employing a Zero-Inflated Ordered Probit (ZIOP) model, which allows us to account for an excessive number of zero observations. Our results are in contrast with previous studies’ results with regard to environmental attitudes and socio-economic profiles of residents. Our findings indicate that the stakeholders living near major roads have higher incentives to offset environmental costs. Also, younger, better educated, and more environmentally-aware citizens are willing to pay more to reduce externalities, as they are influenced by their values and environmentally friendly sub-culture, possibly fostered during the past 30 years of green movement worldwide campaigning.     

重卡提升桥控制系统对比及应用

提升桥的使用,可减轻车辆的自重,降低油耗,减少轮胎的磨损,能为用户带来良好的经济效益。由于通过气囊将提升桥提升,气囊具有良好的非线性弹性特性,用于车辆悬架装置中可以明显改善车辆的操纵稳定性和行驶平顺性,同时可以减轻重载车辆对路面的破坏,在重卡上得到广泛的应用。本文对提升桥悬架结构形式进行简述,对比分析了目前几种提升桥控制系统各自优缺点。     

Violent water-structure interaction: Overtopping features and vertical loads on a fixed structure due to broken incident flows

This paper presents an alternative experimental study of the interaction of broken flows with a fixed structure, concerning the overtopping features and vertical loads over its deck. Wet dam-break tests were carried out to generate incoming flows. Synchronized measurements provided by high-speed cameras, water elevation and force sensors, were used to investigate the influence of tank length in overtopping behaviour and the patterns and loads formed by wet dam-break flows generated by different conditions. During some of the overtopping events analysed, large scale plunging waves were observed, hitting the deck directly and forming large air cavities. These events generated violent interactions with the structure, causing significant loads and chaotic behaviour over the deck, due to the combination of air cavity collapse, reactive splash and run-down. The present approach could be employed as an alternative to study interactions of broken incident flows with different types of fixed structures, allowing the acquisition of detailed data to compare analytical or numerical models.     

大连地铁车站风道风井设置简介

地铁车站风道风井的合理设置对于车站施工工法、地面风井规划、车站规模及工程造价都有很大的影响,详细介绍了大连地铁风道风井设置及环控系统的组成。     

怎样正确使用和保养汽车空调

随着汽车工业的发展和人民生活水平的日益提高,汽车已走进了千家万户。人们不但追求汽车的安全性、可靠性、更注重它的舒适性,汽车空调也就成为现代汽车上的一项基本配置了。因此,车主们对汽车空调的正确使用,如何养等方面知识的需求越来越高多。根据车主们的需求,本文以通俗易懂的形式讲述了调的工作原理、正确使用和维护保养。     

气囊用于大型平底分段合拢的研究

本文就利用气囊进行大型平底分段合拢的方法进行了研究,并就大型分段利用气囊进行工艺合拢的方法进行了设计与方案论证,给出了气囊选型的方法及与其配合的牵引系统的安全工作负荷计算方法.根据现场实际情况,对气囊的受力进行了分析,指出利用气囊技术能够较好的解决大型分段场内搬运与工艺合拢分段间的位置校准问题.为大型分段的制造、场地移动以及分段总组的合拢提供了一种有效的工艺方法.     

车用空气滤清器减声量优化研究

针对某车用空气滤清器分别设计了导流管、1/4波长管和穿孔板结构,并以减声量为评价指标对各种措施的应用效果进行了分析.结果表明,在原空气滤清器上增加3种消声措施后,在保持原空气滤清器宽频带较高消声效果的同时,有效提高了频率在295 Hz、620 Hz和750 Hz下的减声量;改进后空气滤清器的整体减声量为87 dB,比原型提高14dB,对空气滤清器的结构改进达到了较为满意的效果.     

石英砂特性对内燃机空气滤清器原始过滤效率测试结果的影响

对用于内燃机空气滤清器性能评价的A、B、C 3种270目石英砂的粒径分布和形态特性进行了分析,并分别以其为试验尘对空气滤清器的原始过滤效率进行了测试。结果表明,使用石英砂A、B、C作为试验尘时,同一滤清器的原始过滤效率分别为99.30%、99.55%与99.70%。分析了空气滤清器过滤效率和发动机磨损的关系,并得出空气滤清器的灰尘透过率对汽车大修里程有着重大影响的结论。     

微米木纤维发动机空气滤芯过滤机理与试验

介绍了微米木纤维过滤体材料及其过滤机理,分析了微米木纤维空气滤芯的特性.对微米木纤维空气滤清器在稳态和非稳态工况下的过滤效率和过滤阻力进行了数值模拟,并结合空气滤清器模拟试验台进行了试验研究.结果表明,数值模拟与试验结果吻合较好;微米木纤维发动机空气滤清器过滤效率高,过滤阻力小,可满足汽车行业和机械行业标准要求.     

小松EC210Z—1空气压缩机的使用与修理

本文简要介绍了日本小松公司 EC210Z-1空气压缩机的参数、工作原理及特点,着重对故障进行了分析,介绍了修复方法.