迎风旋转——SSB风能系统公司的创新型变桨系统

对风能的利用是一项非常古老的技术,风磨早在几千年前就为人所用.古巴比伦人就已知道利用风能.然而在过去几十年,这项技术才得到了真正的发展.根据在航空领域所了解的知识,首先推进的是现代风电机的空气动力学技术.变桨系统则是过去30年最重大的成就之一.     

Combustion characteristics of hydrotreated vegetable oil – diesel blend under EGR and supercharged conditions

This paper investigates the effects of Hydrotreated vegetable oil-diesel blend to combustion characteristics under various ambient oxygen concentrations and ambient pressure. Combustion characteristics were investigated using heat release rate analysis, two color method, soot concentration measurement and NOx concentration measurement. The experiments were carried out on a rapid compression expansion machine to simulate the ambient condition of a CI engine at TDC. Synthetic gas with oxygen concentrations of 21 %, 15 % and 10 % were used to simulate EGR conditions. A single hole injector was used with five different fuels: commercial diesel, HVO-commercial diesel blends and HVO. The results showed that increasing HVO blending percentages decreased ignition delay, flame temperature, soot concentration and NOx concentration. Heat release at oxygen concentration of 10 % dramatically dropped due to a shortened ignition delay, which resulted in less combustion. A decreased oxygen concentration from applied EGR conditions not only increased ignition delay, heat release, flame temperature and NO_x concentration, but also increased soot concentration. A combination of EGR and supercharged conditions by increasing ambient pressure and decreasing oxygen concentrations resulted in increased heat release, decreased flame temperature, ignition delay and soot concentration, compared to EGR conditions.     

Socioeconomic Conditions and Perceptions of Environmental Risks in the Mekong Delta,Vietnam

This study investigates the effects of sociodemographic and economic status on the differences in environmental awareness, risk perception, and stewardship of the Mekong Delta residents based on a survey conducted in person with 1,006 households across the delta system. Spatial visualization and a multiple correspondence analysis (MCA) were performed on the survey results to discover underlying factors of the participants' responses. The study results revealed that public environmental awareness in the Mekong Delta is still limited. The level of environmental awareness, risk perception, and understanding of stewardship of local people varies by location. Furthermore, how the Mekong Delta dwellers perceive environmental risks and behave toward environmental protection is unlikely to be influenced by their demographic profiles. However, they are significantly affected by the economic status including income levels and sources. Poor economic status was found to significantly hamper pro-environmental behavior of Mekong Delta people regardless of their knowledge of environmental degradation and the related consequences. These findings provide key information to assist policymakers in developing a successful and sustainable disaster risk reduction mitigation plan for the Mekong Delta region. The implications may also be applicable for other coastal zones, which are composed of similar sociodemographic, economic, and environmental conditions.     

欧洲BR189型多流制式电力机车

1999年夏,德国联邦铁路货运公司订购了100台新型BR189电力机车用于货物运输。该新型机车在原BR152的基础上进行必要的改进和研究试验,能够适应4种不同的电流制式和满足跨国运输要求。     

汽车底盘系统零件的振动性能优化技术

汽车振动性能的优化要求对悬架系统的单个零件进行分析,同时考虑它们在振动系统中的相互作用。这一工作的最大挑战在于如何建立简单有效的动力学模型,以便获得用于对零件的性能要求进行详细定义的足够数据。