商业综合体中楼梯、自动扶梯和电梯多通道耦合疏散策略研究*

为选择最优疏散模式,提高商业综合体应急疏散效率,运用Pathfinder仿真软件,求解最优自动扶梯与楼梯双通道耦合模式,并探讨自动扶梯、楼梯与电梯多通道耦合疏散模式实效性。结果表明:自动扶梯与楼梯双通道耦合疏散模式中,自动扶梯双下行与楼梯耦合疏散模式疏散效果最好,疏散时间最短,总疏散时间465.95 s,比单一楼梯疏散模式缩短16.24%;自动扶梯、疏散楼梯与电梯多通道3重耦合疏散模式,比自动扶梯与楼梯双通道耦合疏散模式中最优组合方式疏散时间减少10.45 s,减少了2.24%;通过电梯疏散人数86人,占总疏散人数1.30%,表明电梯疏散效果提升不明显。研究结果可为紧急情况下自动扶梯反转时间确定以及密集场所应急预案编制提供理论参考。     

机场火灾旅客安全态度、风险感知与非适应性疏散行为的关系研究*

为减少旅客非适应性疏散行为,提高机场火灾疏散效率,基于态度-行为过程模型,剖析机场火灾旅客安全态度对非适应性疏散行为的作用机理。构建包含安全态度(安全认知、安全情感、安全行为倾向)、风险感知（概率感知、控制感知、损失感知）和非适应性疏散行为的理论模型,并依据507份有效数据进行实证检验。研究结果表明:安全情感对非适应性疏散行为有直接显著的负向作用,安全认知和安全行为倾向通过风险感知的中介作用对非适应性疏散行为产生负向影响,且安全情感对非适应性疏散行为的总效应最大。     

High efficiency of the NH4H2PO4/Mg(OH)2 composite for guaranteeing safety of wood production

Currently, China's timber industry is in high demand with the development of real estate. However, there is a certain fire hazard in the production process of wood manufacturing. Once a fire occurs, the fire is violent and the spread is rapid. Therefore, to improve the safety of its production process, ammonium dihydrogen phosphate and magnesium hydroxide were selected to prepare a new composite superfine dry powder, which was denoted as the NH₄H₂PO₄/Mg(OH)₂ composite. Furthermore, to figure out dry powders' extinction effect on Class A fire, the wood-crib fire suppression effect of the NH₄H₂PO₄/Mg(OH)₂ composite was test, and then compared with that of ultrafine dry powder (UDP) and commercial ABC dry powder (C-ABC) in a 1 m³ chamber. Three parameters of the fire extinguishing process, namely flame extinction time, powder consumption and temperature drop were adopted to measure the fire suppression performance. The results demonstrated that UDP and C-ABC both had a larger flame extinction time and powder consumption than the NH₄H₂PO₄/Mg(OH)₂ composite. Besides, a fire (wood cribs) can be extinguished by the NH₄H₂PO₄/Mg(OH)₂ composite with the fastest temperature drop and a much-improved toxic gas suppression ability. In short, the NH₄H₂PO₄/Mg(OH)₂ composite can better guarantee the safety of the wood processing production process. Moreover, the reasons for performance advantages of the NH₄H₂PO₄/Mg(OH)₂ composite were discussed.     

地铁站事故疏散时间计算方法对比研究

为提高我国地铁站事故疏散时间计算结果的准确性和可信度,通过对国内外事故疏散时间计算的方法、参数设置、结果可信度的对比分析,总结各种地铁站事故疏散时间计算方法的优缺点。结果表明:我国地铁站事故疏散时间的计算方法存在计算参数设置不合理,安全疏散判定标准和事故状态通行能力不明确,折减系数偏大等问题,同时也忽略了建筑特征、人员属性和火势蔓延对疏散过程的影响;而性能化事故疏散时间计算方法能够很好的解决上述问题。建议摒弃公式计算法,积极推行性能化事故疏散设计方法。     

Posttreatment Tree Mortality After Forest Ecological Restoration,Arizona, United States

Pine–oak forests are of high ecological importance worldwide, but many are threatened by uncharacteristically severe wildfire. Forest restoration treatments, including the reintroduction of a surface fire regime, are intended to decrease fire hazard and emulate historic ecosystem structure and function. Restoration has recently received much management attention and short-term study, but little is known about longer-term ecosystem responses. We remeasured a replicated experimental restoration site in the southwestern United States 5 years after treatments. Basal area, tree density, and canopy cover decreased in the treated units at a faster rate than in controls. Delayed mortality, not evident right after treatment, decreased density modestly (13% in treated units and 10% in controls) but disproportionately affected large trees (“large” ponderosa pines were those with diameter at breast height [dbh] ≥37.5 cm; other species dbh ≥20 cm). In treated units, 10.9 large trees ha^–1 died, whereas 6.2 trees ha^–1 died in control units. Compared with reference conditions, the experimental blocks remained higher in pine density and, in three of the four blocks, in basal area. Pine trees grew significantly faster in treated units than in controls, enough to reach the reference level of basal area in 6 years. Although mortality of large trees is a concern, the treated units have vigorous growth and low density, indicating that they will be relatively resistant to future drought and fire events. Similar treatments may be beneficial in many areas of the United States and in related pine-oak ecosystems elsewhere.     

Some basic principles of grassland fire management

Fire management of grasslands is best executed based on an understanding of the fundamental properties of grassland components, structures, and environments, and the nature of fire behavior in grassland fuels. The art of controlled burning combines experience, practicality, empirical knowledge, and sensitivity, with the effects of fire, the role of fire (particularly under natural conditions), inherent climatic conditions, and sound ecological management objectives. Some of the properties, effects, roles, conditions, experiences, and objectives of grassland burning are presented.     

The dissolution of cooperative groups: mechanisms of queen mortality in incipient fire ant colonies

In several species of ants, queens often form temporary cooperative associations during colony foundation. These associations end soon after the eclosion of the first workers with the death or expulsion of all but one of the queens. This study examined competition between foundress queens of the fire ant Solenopsis invicta. Although attacks by the workers contributed to queen mortality, queens gained no advantage by producing more workers than their co-foundresses. Restriction fragment length polymorphism analysis of mitochondrial DNA showed that the queen producing more workers during colony founding was no more likely to survive than the less productive queen. In experimentally manipulated colonies in which all the workers were daughters of only one of the queens, the mother of the workers was no more likely to survive than the unrelated queen. Queens producing diploid males reared fewer offspring but were as likely to survive as queens producing only workers. These results suggest that workers do not discriminate between related and unrelated queens within colonies. Aggressive encounters between queens were common. Queens were more likely to die or be expelled if paired with heavier queens or if they lost more weight than their co-foundress during the claustral period. Finally, when queens were separated by screens through which workers could pass, the workers usually attacked and killed the queen farther from the brood. These results suggest that queen survival is promoted by a high fighting ability relative to co-foundresses, rather than by increased worker production, and that workers respond to queen differences that are independent of kinship. Received: 8 September 1995/Accepted after revision: 5 March 1996     

火灾时人员安全疏散可靠性评估

本文给出了一个计算人员安全疏散概率的算法，用以评价火灾时室内人员的危险程度。算法假定影响安全疏散的变量为随机变量，以逃生概率做为疏散评价指标，文中附有算例。     

火灾情况下疏散心理和行为在不同层次起点学生中的差别研究

为了研究火灾条件下疏散心理和行为在不同层次起点学生中的差别,有针对性地进行消防安全教育和管理,完善消防安全应急预案,采用现场实验的方法对不同层次起点的高职生群体进行问卷对比研究。采用世界先进统计软件SPSS12.0forWindows进行对比分析,其结果显示:在火灾情景下,起点较高的学生较之起点较低的学生存在较弱的恐惧心理,能做到就近逃生,而非局限于安全通道,相互救助心理和行为较弱;起点较高的学生较之起点较低的学生消防意识强,掌握的消防知识较多,重返心理和行为较弱,灭火心理和行为也较弱。该研究方法科学、先进,结果可信。不仅为密集场所的消防工作提供了参考,而且对充实我国的消防心理学、火灾心理学、社会心理学等学科也有理论意义。