火灾模型对钢交错桁架结构性能化抗火设计的适用性分析

对目前性能化防火设计中常用的4种火灾作用模型进行了分析和总结,并运用这4种模型对钢结构交错桁架在火灾时的热环境进行了模拟,分析不同火灾作用模型下该体系的结构响应,研究不同火灾作用模型对交错桁架结构性能化抗火设计的适用性。研究表明:火源功率、火灾载及火灾持续时间等因素对钢结构交错桁架的抗火分析具有重要影响。国际标准升温曲线和参数化室内升温曲线不考虑火源功率、建筑通风口等因素,缺乏针对性,分析结果偏于保守;区域模型所得温度偏低,不宜用于交错桁架结构的性能化抗火设计;场模型考虑了火源功率及环境温度分布的不均匀性,和实际火灾较接近,计算结果相对较为准确,可用于结构的性能化防火设计。     

火灾环境下多层建筑的人员疏散路径模型研究

针对公共路段人员交汇出现的疏散速度减缓问题,构建了一个多层建筑的人员疏散最优路径模型。该模型以优先满足疏散时间较长的楼层为前提,保证任意时刻任意路径的人员流量不为零,同时优先使最短路径达到人员流量饱和,在此基础上对其算法步骤进行了改进。最后结合实例进行验证,结果表明,本模型可以更加准确地预估疏散所需时间。     

不同坡度对正庚烷流淌火燃烧特性的影响

针对液体燃油储运过程中泄漏引发的火灾爆炸事故,设计并搭建流淌槽坡度可调式液体燃油流淌火燃烧试验平台,开展连续泄漏正庚烷流淌火试验。选择水平表面(0°)流淌试验作为基准,改变流淌槽的坡度(0.5°,1°和3°),研究分析不同泄漏速率下连续泄漏正庚烷流淌火的燃烧面积、燃烧速率等燃烧特征参数的变化规律。结果表明:1)连续泄漏正庚烷流淌火燃烧特征参数均随泄漏速率增加而明显增加;2)坡度对连续泄漏正庚烷流淌火燃烧特性影响显著,即使流淌槽坡度增加0.5°,其燃烧特性即发生明显改变;3)连续泄漏正庚烷流淌火的平均稳定燃烧速率随流淌槽坡度的增加反而减小。     

楼梯间电动车火灾数值模拟研究

楼梯井电动车火灾呈典型的烟囱效应现象,短暂燃烧,浓烟迅猛,往往危害很大。模拟结合全尺寸实验结果,基于FDS软件对电动车在楼梯井内燃烧进行动态仿真,相关数据进行对比分析。研究结果表明:物理实验数据与数值模拟数据比较吻合,楼梯间平均温度370℃左右,最高温度超过1 000℃,楼梯间浓烟毒性很大;火焰卷吸处上方的无量纲温度随楼梯井竖直高度的增加而减小,同一区域的近墙处温度较高;火灾后期在喷淋作用下,CO浓度在火灾熄灭阶段有所增加。     

一种基于数据融合的林火火线动态蔓延预测方法的研究

准确预测林火蔓延对于有效防治野火危害具有重要意义。传统林火蔓延速度场经验模型需要可燃物特性、坡度、温度及湿度等众多实测参数,由于参数均具有不同的时空分布,限制了模型的实际应用。因此提出速度场实时测量及水平集法模拟林火蔓延两种技术相结合的方法,通过测定火蔓延锋面的位置获取当前时刻锋面处的速度场分布并对此速度场在未燃烧区域进行延拓,结合水平集法预测林火蔓延,并使用数值模拟及实验数据验证了该方法能够有效预测短期内林火蔓延趋势,得出基于速度场的数据融合方法可满足实际林火蔓延建模的需求。     

城市消防安全影响因素及评估体系研究——以海南某沿海城市为例

在前人评估重点研究公共消防基础、灭火救援力量的基础上,增加消防安全形势、火灾防控工作对城市消防安全影响因素的研究,以海南某沿海城市为例,采用层次分析法构建城市消防安全评估体系,设置定量化评分判定基准,运用模糊集值统计法计算得分。评估结果表明体系更真实地反映了该市消防安全现状及火灾防控薄弱环节,最后针对高风险项提出具体改进措施。该体系模型丰富了评估指标数量;宏观考虑了该市热带气候、旅游型城市特征、火灾情况对消防安全形势的影响;更重要的是,提出将社会面火灾防控工作纳入评估体系。研究对于城市消防安全评估的宏观化、系统化、地域化、实用化、定量化都有一定参考意义。     

高层建筑电气火灾隐患因子定量分析方法研究

为了对高层建筑电气火灾隐患排查进行定量化分析,采用解释结构模型构建高层建筑电气火灾隐患因子的复杂逻辑模型;在利用德尔菲法确定隐患因子初始概率的基础上,经过交叉影响分析法求解交叉影响概率矩阵;引入马尔科夫链修正各隐患因子交叉影响后的概率,得到火灾隐患因子的稳态概率矩阵。研究结果表明:各隐患因子的马尔科夫链校正概率比德尔菲法测定的初始概率更加准确,该计算排序结果可明确高层电气火灾隐患排查和管控的重点。     

Is being a leader a mixed blessing? A dual‐pathway model linking leadership role occupancy to well‐being

Recent leadership research has drawn greater attention to how the well‐being of leaders influences leadership behaviors, follower performance and well‐being, and overall leadership effectiveness. Yet little attention has been paid to the relationship between occupying leadership positions and job incumbents' well‐being. This research addresses this question by developing and testing a dual‐pathway model. Our model proposes that incumbency in leadership positions is positively related to high levels of both job demands and job control, whereas job demands and job control have offsetting effects on well‐being. Results based on a longitudinal sample revealed that employees who transitioned from nonleadership positions to leadership roles showed trajectories of increasing job demands and job control, whereas such trends were weaker among those who remained in nonleadership positions. Findings from three additional samples generally demonstrated that leadership role occupancy was indirectly related to various indices of psychological and physiological well‐being through job demands and job control. Because the signs of the indirect effects through job demands and job control differed in expected ways, the overall relationship between leadership role occupancy and the well‐being outcomes was generally small and nonsignificant. We discuss research and practical implications of our framework and findings for organizations, employees, and leaders.     

A meta‐analysis of the antecedents of work–family enrichment

This study meta‐analytically examined theoretically derived antecedents of both directions of work–family enrichment (sometimes labeled facilitation or positive spillover), namely, work–family enrichment and family–work enrichment. Contextual and personal characteristics specific to each domain were examined. Resource‐providing (e.g., social support and work autonomy) and resource‐depleting (e.g., role overload) contextual characteristics were considered. Domain‐specific personal characteristics included the individuals' psychological involvement in each domain, the centrality of each domain, and work engagement. Results based on 767 correlations from 171 independent studies published between 1990 and 2016 indicate that several contextual and personal characteristics have significant relationships with enrichment. Although those associated with work tend to have stronger relationships with work–family enrichment and those associated with family tend to have stronger relationships with family–work enrichment, several antecedent variables have significant relationships with both directions of enrichment. Resource‐providing contextual characteristics tend to have stronger relationships with enrichment than do resource‐depleting characteristics. There was very little evidence of gender being a moderator of relationships between contextual characteristics and enrichment. Lastly, meta‐analytic structural equation modeling provided evidence that a theoretical path model wherein work engagement mediates between several contextual characteristics and enrichment is largely generalizable across populations.     

Feeling interrupted—Being responsive: How online messages relate to affect at work

Being constantly connected to others via e‐mail and other online messages is increasingly typical for many employees. In this paper, we develop and test a model that specifies how interruptions by online messages relate to negative and positive affect. We hypothesize that perceived interruptions by online messages predict state negative affect via time pressure and that perceived interruptions predict state positive affect via responsiveness to these online messages and perceived task accomplishment. A daily survey study with 174 employees (a total of 811 day‐level observations) provided support for our hypotheses at the between‐person and within‐person level. In addition, perceived interruptions showed a negative direct association with perceived task accomplishment. Our study highlights the importance of being responsive to online messages and shows that addressing only the negative effects of perceived interruptions does not suffice to understand the full impact of interruptions by online messages in modern jobs.