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401.
可燃物表面积和厚度对建筑物内火灾载荷的影响   总被引:1,自引:0,他引:1  
火灾载荷是判断建筑物室内火灾危险程度的依据,以前人们对火灾载荷的研究局限于只考虑可燃物的种类和量,并没有考虑到可燃物的形状、厚度和摆放位置对火灾载荷的影响。该文建立了简单的模型讨论了可燃物的表面积和厚度对火灾载荷的影响,并应用这种模型对三个典型的建筑房间进行了火灾载荷的研究,取得了较好的结果。  相似文献   
402.
火对人类生存和繁衍具有历史性的变革作用 ,同时火灾事故的发生又给人类带来了威胁。笔者以有关文献数据为依据 ,以现有的省域为地理界限并以规定的时间段为基础 ,对中国历史上的火灾事故及其原因进行简要统计分析 ,其中的数据来源难免有一定的局限性 ,要从中得出一些规律确实很难 ,但至少可总结出 :①中国历代火灾多发区的变迁过程 ,基本上是随中国经济和文化中心的迁移而迁移的 ;经济越发达地区 ,同期火灾事故明显居多 ;火灾的直接受害者主要是平民百姓和宗教人士。②在已知的火灾事故原因中 ,战争是第一位的。上述分析的结论 ,对当代人们了解过去的火灾史 ,具有帮助与启迪。  相似文献   
403.
改革开放和社会进步,给消防工作的发展提供了难得的机遇和挑战。强化政府消防行政职能,改善消防安全环境,构建服务型消防管理新模式成为社会发展的必然。本文分析了当前政府在消防行政管理中存在的问题,从消防行政管理理念、消防监督模式以及消防工作机制等方面给出了构建服务型消防行政管理模式的对策。  相似文献   
404.
本文简析了甘肃省武威市凉州区西营灌区饮水安全工程的管理、水质监测和水源地保护等方面采取的措施,并就出现的问题提出了一些对策,以期促进该灌区饮水安全工程的科学发展。  相似文献   
405.
This study analyses the influence of gift giving, geographical location, political regime, and trade openness on disaster donation decisions, using five severe earthquakes that occurred between 2008 and 2012 as case studies. The results show that global disaster donation is not dominated by only philanthropy or trade interests, and that the determinants of donation decisions vary with the scale of the natural disaster and the characteristics of the disaster‐affected countries. While gift giving exists in the case of middle‐size earthquakes, political regimes play a very important part in the overall donation process. Countries with higher perceived corruption may donate more frequently, but those that are more democratic may be more generous in their donations. Generosity based on geographical proximity to the calamity is significant in the decision‐making process for most natural disasters, yet it may have a negative effect on donations in Latin America and the Caribbean.  相似文献   
406.
The aging of many of the installations in the oil and gas industry may increase the likelihood of loss of containment of flammable substances, which could lead to major accidents. Flame temperatures in a typical hydrocarbon fire may reach 1100–1200 °C, which are associated with heat flux levels between 250 and 350 kW/m2. To limit or delay the escalation of an initial fire, passive fire protection (PFP) can be an effective barrier. Additionally, both equipment and piping may require thermal insulation for heat or cold conservation. Previous studies have investigated whether thermal insulation alone may protect the equipment for a required time period, e.g., until adequate depressurization is achieved. The present study entails the development of a numerical model for predicting the heat transport through a multi-layer wall of a distillation column exposed to fire. The outer surface is covered by stainless-steel weather protective cladding, followed by PFP, thermal insulation, and finally an inner column of carbon steel of variable thicknesses. The model for the breakdown of thermal insulation is based on observed dimensional changes and independent measurements of the thermal conductivity of the insulation after heat treatment. The calculated temperature profiles of thermally insulated carbon steel during fire exposure are compared to fire test results for carbon steel with thicknesses of 16, 12, 6 and 3 mm. The model's predictions agree reasonably well with the experiments. The degradation of the thermal insulation at temperatures above 1100 °C limits its applicability as fire protection, especially for low carbon-steel thickness. However, the model predicts that adding a 10-mm layer of more heat-resistant insulation (PFP) inside the fire-exposed cladding may considerably extend the time to breakdown of the thermal insulation.  相似文献   
407.
Climate change models for California's Sierra Nevada predict greater inter-annual variability in precipitation over the next 50 years. These increases in precipitation variability coupled with increases in nitrogen deposition from fossil fuel consumption are likely to result in increased productivity levels and significant increases in forest understory fuel loads. Higher understory plant biomass contributes to fuel connectivity and may increase future fire size and severity in the Sierra Nevada. The objective of this research was to develop and test a model to determine how changing precipitation and nitrogen deposition levels affect shrub and herb biomass production, and to determine how often prescribed fire would be needed to counter increasing fuel loads. Model outputs indicate that under an increasing precipitation scenario significant increases in shrub and herb biomass occur that can be counteracted by decreasing the fire return interval to 10 years. Under a scenario with greater inter-annual variability in precipitation and increased nitrogen deposition, implementing fire treatments at an interval equivalent to the historical range of 15–30 years maintains understory vegetation fuel loads at levels comparable to the control.  相似文献   
408.
409.
Responding differentially to kin and non-kin is known to be adaptive in many species. One example is the inclusive fitness benefits of reducing aggression toward closer relatives. Little is known, however, about the ability of animals to assess differential degrees of genetic relatedness and to respond accordingly with differential levels of aggression. In the present study, we tested whether aggressiveness between body mass-matched pairs of fire salamander (Salamandra infraimmaculata) larvae covaried with the genetic similarity between them. We quantified aggressiveness at three levels of genetic similarity by selecting pairs within and across pools from recently genotyped populations. We also assessed aggression between pairs of siblings. Aggression and associated injuries decreased as genetic similarity increased across the groups. These findings suggest that cannibalistic salamanders can assess their degree of genetic relatedness to conspecifics and vary their behavioral responses depending on the degree of similarity between them along a genetic relatedness continuum.  相似文献   
410.
Assessing drought-related ecological risk in the Florida Everglades   总被引:6,自引:0,他引:6  
In the winter-spring of 2001, South Florida experienced one of the worst droughts in its recorded history. Out of a myriad of ecological concerns identified during this time, the potential for catastrophic peat fire and negative impacts to wading bird reproduction emerged as critical issues. Water managers attempted to strike a balance between the environment and protection of water supplies for agriculture and urban interests. It became evident, however, that a broad-scale, integrated way to portray and prioritise ecological stress was lacking in the Florida Everglades, despite this being considered a necessary tool for addressing issues of environmental protection. In order to provide a framework for evaluating various water management operations using real-time information, we developed GIS-based indices of peat-fire risk and wading bird habitat suitability. These indices, based on real physical, chemical, and biological data, describe two ecological conditions that help define the physical and biological integrity of the Everglades. In addition to providing continuous, updated assessments throughout the drought period, we incorporated predictive models of water levels to evaluate how various water management alternatives might exacerbate or alleviate ecological stress during this time.  相似文献   
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