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61.
62.
63.
Kai Kang 《Fire Technology》2007,43(4):331-346
This paper presents an emergency evacuation analysis during a mid-platform train fire in an underground rail station. A time-based
evacuation scenario is developed taking into account the stairway inaccessibility due to smoke blockage. The calculation approach
in NFPA 130 is then applied to a parametric study of this time-based scenario and its reliability is examined using a micro-simulation
model. Both methods give consistent predictions of the exiting times. The results demonstrate that with the division of the
station into two zones, the exiting time could not meet the code requirements, whereas it does meet the required exiting time
without the division. Such division is due to smoke blockage and creates an uneven ratio of the occupant load to the available
exiting capacity. This shows that appropriate consideration of the fire and smoke effects is important for station egress
evaluation. Other issues such as the fire growth rate and the pre-evacuation time are also discussed. 相似文献
64.
65.
Open window buses without air-conditioning are a major mode of urban and inter-city transport in most countries. High occupancy
combined with hot and humid conditions makes travel in these buses quite uncomfortable. In this study air flow through a bus
has been studied that could be the basis for low cost and eco-friendly methods of increasing passenger comfort and possibly
reduce drag. The aerodynamics of such a road vehicle has not been studied as previous investigations have been confined to
vehicles with closed windows that present a smooth exterior to air flow. Using a 1:25 scaled Perspex model of an urban bus
in Delhi, flow visualization was performed in a water channel. The Reynolds numbers were one-tenth of a real bus moving at
10 m/s. Smoke and tuft visualizations were also performed on an urban bus at 40 km/h. Numerical simulations were performed
at the actual Reynolds number. Even though there were Reynolds number differences, the broad features were similar. Air enters
the bus from the rear windows, moves to the front (relative to the bus) and exits from the front windows. Inside air velocity
relative to the bus is about one-tenth of the free-stream velocity. The flow is highly three-dimensional and unsteady. 相似文献
66.
Hermann Knoflacher 《Sadhana》2007,32(4):293-307
Technological determinism has become a kind of religion for many people since it appears to offer solutions for societal problems
as never before in history. Transport is one of the fascinating technology branches developed during the last 200 years. Effortless
movement over long distances has become possible for car users as long as cheap fossil energy is available. However, the effect
of fast transport on urban structures and society was not taken into account when developing these technical means. Technologists
and economists have used indicators for expected benefits of these fast transport modes without taking into account the real
system effects on society and urban structures. Plausible assumptions and hopes instead of scientific understanding of the
complex system are used in practice. In contradiction to widely held beliefs of transportation planners, there is actually
no growth of mobility if counted in number of trips per person per day, no time saving by increasing speed in the system,
and no real freedom of modal choice. Modal choice is dependent on physical and other structures, the artificial environment
built by urban planners, transport experts and political decisions. The core hypothesis of traditional urban and transport
planning ‘growth of mobility’, ‘travel time saving by increasing speed’ and ‘freedom of modal choice’ are myths and do not
exist in the real urban and transport system. This is the reason why urban planning and transport planning based on traditional
non-scientific assumptions is creating continuously not only more transport problems, but also environmental and social as
well as economic problems all over the world, where these principals are applied. Urban transport planning in Europe, understanding
the transport system and the solutions are presented in this paper. 相似文献
67.
岩盐钻井水溶双井连通开采工艺的研究与推广 总被引:1,自引:0,他引:1
文章就全国井矿盐采区多年的开采工艺技术,进行了系统的研究与总结,并提出了岩盐钻井水溶开采双井连通的各种开采工艺及其关键技术,具有很强的适用性和推广价值。 相似文献
68.
重轨钢非铝脱氧工艺研究 总被引:6,自引:0,他引:6
介绍了攀钢重轨钢非铝脱氧工艺,在满足钢中脆性夹杂物控制的前提下,采取“预脱氧+终脱氧”的工艺,达到钢液脱氧良好,钢轨内部质量大幅提高,钢轨T[O],[Al]及氧化物夹杂评级完全满足200km/h高速铁路钢轨标准的要求。 相似文献
69.
详细阐述了滴注式直-压淬两用双排气体渗碳自动线的组成单元,渗碳气氛、工艺柔性化、设计特点以及工艺调试;生产实践证明:自动线运行可靠.稳定,主要技术性能和指标达到或优于国家标准。 相似文献
70.