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381.
The effects of off-road vehicles (ORVs) on the dune system of Fire Island National Seashore, New York, USA, were examined through a detailed, two-year field study. The experimental approach was adopted in order to evaluate the environmental effects of ORVs in this zone. Adjacent control and impact sites were established in two locations. Vehicle impacts were applied at the equivalent rate of one vehicle pass per week. Monitoring of foredune vegetation through sequential quadrat surveys and construction of sea-ward limit maps showed a significant loss of vegetation resulting from ORV impacting. Loss of vegetation resulted in an alteration of the natural foredune profile, which could increase dune erosion during storm wave attack. 相似文献
382.
采场调压数学模型在煤矿火区治理中的应用 总被引:1,自引:0,他引:1
采场调压可改变采场内气体流动的状况,抑制采空区自然发火。笔者采用Ward 非线性运动方程,建立采场调压数学模型,利用有限元法对其进行求解。通过对小恒山煤矿东正巷出口的调压进行计算机模拟,从而掌握火区内部参数的变化趋势,及时预测调压潜力及效果,指导调压措施的进一步实施。 相似文献
383.
受限空间烟气运动盐水模拟研究的现状和展望 总被引:1,自引:0,他引:1
回顾了受限空间火灾烟气运动盐水实验模拟研究的发展历史;介绍了盐水实验模拟的理论基础及其在火灾烟气运动研究领域的应用情况和最新进展;分析和讨论了模拟研究过程中所存在的主要问题及其可能的解决方法。所有这些研究和探索,对于受限空间火灾烟气运动盐水实验模拟研究方法的创新和完善有重要的启发作用。 相似文献
384.
运用系统安全工程方法对火灾事故危险源的辩识、评价及控制进行分析,提出火灾事故危险源辩识、评价及控制的方法。 相似文献
385.
The present study introduces an innovative approach to the detailed simulation of the pressure build-up in equipment containing saturated liquids when exposed to fire. The approach is based on the adoption of a fully three-dimensional (3D) computational fluid dynamics (CFD) model of the inner fluid. Experimental data gathered from literature studies were used to validate the model considering vessels of several scales and geometries exposed to a full engulfing pool fire. The comparison between the results of the 3D CFD model developed and those of two-dimensional (2D) literature models was also carried out. This enabled deriving precise indications on the selection of the most suitable approach based on the type of accidental scenario to reproduce, confirming 2D models as sound and reliable tools to model the fluid behaviour when homogeneous heat exposure conditions are present. On the other side, limitations of 2D approaches in capturing edge effects on i) temperature profiles, ii) recirculation patterns, and iii) energy accumulation in the vessel lading during fire exposure were identified and discussed. The results obtained represent a valuable source of information to support risk management and emergency response planning. 相似文献
386.
火焰锋面的追踪是建立林火蔓延模型及预测锋面位置的关键环节。基于水平集法追踪锋面具有求解灵活稳定、易于处理锋面拓扑结构变化的特点。针对传统水平集法重新初始化过程复杂、计算量较大的问题,根据距离函数定义,提出通过形态学膨胀的方法以锋面点为圆心向外膨胀,获得锋面附近窄带内每个点距离锋面的最近距离,重建窄带内的水平集函数,物理意义明确,有效减小了计算量,在此基础上基于林火速度场经验模型模拟了单火源及双火源的锋面蔓延情况。结果表明,该方法能够有效模拟坡度、风速等因素对火焰锋面的影响,为其在林火蔓延模型中的应用提供了基础。 相似文献
387.
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389.
In this research, we constructed a three-dimensional fire risk analysis technique (3D-FRAT) for common building fires. To demonstrate its effect, the 3D-FRAT employed a self-developed 3D risk-calculating module in combination with the Fire Dynamics Simulator (FDS) software to simulate the Welcome Restaurant accident that happened on February 15, 1995 in Taichung City, Taiwan. This study only focuses on thermal radiation and provide a preliminary method to quantify a fire risk. Different firefighting equipment that comply with the related building and fire-preventive regulations have been used in the simulations to test their mitigating effectiveness on the accident. The results were shown by animation, 3D pictures, and sliced pictures to facilitate the researchers’ understanding of human hazards caused by thermal radiation or smoke in a specific fire accident. The minimal personnel escaping times for different hazardous factors were estimated; various firefighting designs that can reduce loss of human life and property were also perused. According to the simulation results, the individual risk values in Welcome Restaurant were between 3.108 × 10−9 to 2.719 × 10−5 (deaths/year). It is foreseeable that the 3D-FRAT can become a useful tool for related organizations to choose better fire-resistant buildings or fire-fighting equipment in the future. 相似文献
390.