Numerical simulation of small-scale pool fires of LNG

Liquefied natural gas (LNG) has been largely indicated as a promising alternative solution for the transportation and storage of natural gas. In the case of accidental release on the ground, a pool fire scenario may occur. Despite the relevance of this accident, due to its likelihood and potential to trigger domino effects, accurate analyses addressing the characterization of pool fires of LNG are still missing.In this work, the fire dynamic simulator (FDS) has been adopted for the evaluation of the effects of the released amount of fuel and its composition (methane, ethane, and propane), on the thermal and chemical properties of small-scale LNG pool fire. More specifically, the heat release rate, the burning rate, the flame height, and thermal radiation, at different initial conditions, have been evaluated for pool having diameter smaller than 10 m. Safety distances have been calculated for all the investigated conditions, as well.Results have also been compared with data and correlations retrieved from the current literature. The equation of Thomas seems to work properly for the definition of the height over diameter ratio of the LNG pool fire for all the mixture and the investigated diameters.The addition of ethane and propane significantly affects the obtained results, especially in terms of radiative thermal radiation peaks, thus indicating the inadequacy of the commonly adopted assumption of pure methane as single, surrogate species for the LNG mixture.     

基于改进TOPSIS的受灾点需求紧迫性分级研究

地震发生初期,各受灾点对物资需求的紧迫性存在差异。在应急资源有限的情况下,为提高救援效率,应急资源需要按照受灾点需求紧迫性优先级进行分配和调度。首先,构建了受灾点需求紧迫性评价指标体系,并采用博弈论方法将熵权法和层次分析法相结合,确定权重组合系数及各评价指标综合权重。其次,利用马氏距离和灰色关联分析改进TOPSIS方法,建立了受灾点应急物资需求紧迫性分级模型。最后,将模型应用于受灾点应急物资需求紧迫性分级研究,并将该评价结果与传统TOPSIS法的评价结果进行比较,结果表明,该评价方法可以科学、客观地确定权重组合系数,消除指标间相关性,使评价结果符合实际情况,表明该评价方法科学、可行、有效,能为应急救援物资配送提供有效支持和决策。     

陆上原油长输管道泄漏爆炸事故情景构建研究

以某陆上原油长输管道为例,设定了陆上原油长输管道泄漏爆炸事故情景背景信息及演化过程,从预防、准备、预警、响应、恢复等阶段,梳理分析了事故情景应对全过程的任务及职责主体;针对各项任务从计划预案、人员队伍、装备物资、培训演练、运行机制等方面开展了情景应对能力评估;并针对存在的差距和不足,从企业和政府2个层面提出了针对此类情景的应急能力提升对策建议。该研究可为相关政府及企业加强油气长输管道事故应急准备能力建设提供参考。     

生态旅游区不同距离带上植物群落的结构对比

通过对芦芽山自然保护区植物群落的结构分析 ,揭示旅游活动和群落演替的内在机理 ,为景区植被保护和旅游管理提供依据 .结果表明 :不同地段上各植被层由于各种因素的影响而有所不同 ,大部分景区的植被生长良好 .不同距离带上各植被层大致表现出近距离 <中距离 <远距离的格局规律 ,但其明显度不尽一致 ,说明各植被层反映旅游活动对群落结构作用程度的能力大小依次为乔木层 <灌木层 <苔藓层 <草本层 .5个旅游影响因子的变化趋势 ,反映了旅游活动对群落生态环境的结构作用的规律 .距游径的水平距离愈远 ,垃圾量愈少 ,林下死枝下高愈高 ,枯层愈厚 ,树桩量愈多 ,幼苗量也愈多 .不同距离带上的变化规律客观地描绘了旅游活动的规律性变化 ,近距离处旅游活动强度最大 ,中距离处次之 ,远距离处则最小 .图 1表 1参 8     

Does information of predators influence general wariness?

Antipredator behavior includes several qualitatively distinct activities, but few studies have determined the degree to which these activities are independent. If behaviors are not independent, then the nature of the relationship would illustrate potential performance constraints. We studied crimson rosellas (Platycercus elegans) and first focused on acoustic predator discrimination. We measured time allocation before and after playback of one of three experimental treatments (peregrine falcons—Falco peregrinus, wedge-tailed eagles—Aquila audax, and crimson rosellas) to determine whether or not rosellas discriminated predators from non-predators, and specifically whether or not they discriminated large from small predators. We then focused on the decision to flee. We experimentally approached subjects and measured the distance at which they oriented to us (alert distance) and the distance at which they fled (flight initiation distance; FID). We found that rosellas could distinguish among predators; however, there was no effect on general wariness as measured by FID. These two processes of antipredator behavior may, thus, be independent.     

基于放射源理论的区域生态系统评价方法

研究区域生态系统定量评价方法对区域生态系统的建设与保护具有十分重要的意义。从放射源理论出发,首次将生态影响距离、生态源及生态影响效应的概念引入分析评价中,提出了区域生态系统的定量评价方法,并建立了基于景观空间格局的区域生态系统生态影响的定量计算公式。甘垛镇新庄片和横泾镇沿荡片的应用实例表明,该方法原理简明、结果直观,为区域生态系统的科学评价提供了定量评价方法。     

The effect of ambient temperature on forager sound production and thoracic temperature in the stingless bee, <Emphasis Type="Italic">Melipona panamica</Emphasis>

Foragers of the stingless bees genus Melipona may produce intranidal sounds that are correlated with food location and quality. In this study, we provide the first detailed analysis of pulsed sounds produced by Melipona panamica foragers while feeding on a carbohydrate food source. We trained foragers to a 2.5-M sucrose feeder under normal, ambient temperature (23–33°C) and lower temperature (11–25°C) conditions. We recorded forager sounds under both conditions and tested the effect of temperature of the thorax, feeder plate, and air on sound temporal characteristics. Forager energetic expenditure and the number of pulses per visit were significantly higher in the cold condition than in the normal condition. Foragers spent a longer time at the feeder under the cold condition than during the normal condition. Interpulse durations were significantly shorter in the cold condition than in the normal condition and became progressively and significantly shorter at the end of each performance. Thus, pulse production increased before departure. Foragers increased their thoracic temperatures above ambient at all experimental air temperatures. Under chilled conditions, foragers had a significantly greater difference between thorax temperature and ambient air temperature than under normal conditions. Foragers must achieve a minimum flight muscle temperature before take-off, and thus forager sounds may be linked to muscle warm-up.     

湿式煤气柜施工安全措施的制订

针对正在运行的湿式煤气柜防火间距不够的位置动火建造大10倍的湿式煤气柜的实际情况,采取现场调查、安全系统分析,制订切实可行的措施,顺利完成施工任务。