天然气管道泄漏火球事故后果模拟评价

天然气管道发生泄漏时,大约90%的气体产生燃烧并形成火球,遇火源即发生危害性非常大的火球爆炸事故。本文针对城市天然气管道泄漏事故,综合考虑天然气泄漏后可能发生的火球燃烧和爆炸,利用爆炸冲击波和火球热辐射模型对天然气管道(完全破裂)在发生泄漏时发生火球爆炸进行计算,结果表明:2分钟内泄漏天然气云团超压爆炸的死亡半径和热辐射的火球半径分别高达39.44m和92.93m。因此,通过计算天然气泄漏火球事故爆炸和热辐射范围,对天然气火球爆炸事故预防与应急救援具有一定的意义。     

Sleepwalking into lock-in? Avoiding wrongs to future people in the governance of solar radiation management research

ABSTRACT

Arguments are advanced for two ways in which we can avoid the reckless endangerment of future people in the governance of solar radiation management (SRM) research, which could happen through lock-in to SRM deployment from research. SRM research is at an early stage, one at which the mechanisms of lock-in could start to operate. However, lock-in fit to endanger future people could be slowed or stopped through targeted governance. Governance of SRM research that does not include provisions to detect, slow, or stop lock-in fails the test of an intergenerationally adequate precautionary principle, and research governed without these provisions cannot itself be justified as a precaution against the impacts of climate change.     

Sensitivity of modelled gross primary productivity to topographic effects on surface radiation: A case study in the Cotter River Catchment, Australia

Gross primary productivity (GPP) is a critical response variable for many environmental problems, including terrestrial carbon accounting and the calculation of catchment water balances. Various approaches for modelling GPP have been developed and applied at continental and landscapes scales, but little attention has been given to the sensitivity of GPP to the spatial scale of its driving variables. A key driving variable is surface radiation (R_s) which is influenced by both meso-scale factors (latitude, time of year, cloudiness) and the topographic variables of slope, aspect and horizon shading. We compared the sensitivity of modelled GPP to two different sources of surface radiation (R_s): (1) the ANUCLIM method which only captures the meso-scaled factors; and (2) the SRAD method which incorporates the topographic effects GPP was calculated using the radiation use efficiency (RUE) model (Roderick et al., 2001) to discern general patterns of vegetation productivity at a sub-catchment (i.e. sub-water shed) scale. The radiation use efficiency approach uses the normalized difference vegetation index (NDVI) derived from satellite data (MODIS TERRA), along with estimates of solar radiation at the top of the atmosphere (R_o) and canopy (R_s). In this approach, R_o and R_s capture the influence of diffuse irradiance in canopy photosynthesis and vegetation productivity respectively. This research showed that R_s calculated using the SRAD program provides important discrimination of GPP regimes at a sub-catchment scale, as the result of minimum and maximum daily radiation varying between shaded and exposed surfaces. However, mean daily radiation at a whole-of-catchment scale did not differ between the two sources as the differences in the minimum and maximum daily values tend to cancel each other out. Applications of GPP models therefore need to consider whether topographic factors are important and select the appropriate source of R_s values. GPP models should also reflect understanding of radiation use efficiency. However, further research is required especially with respect to the influence of water stress on plant response.     

核应急辐射环境监测的准备和响应

日本核泄漏事故引发的核危机为人类安全和平地利用核能又一次敲响了警钟.核事故应急工作作为减小核电站危害环境和公众安全的最后屏障,将起到重要的作用,必须做好相关的准备和响应工作.核应急辐射环境监测工作是核应急工作的重要组成部分,在对核应急辐射环境监测进行准备和响应时主要遵循实用性、适用性和适度性并兼顾常规和应急监测的“平战...     

核与辐射事故防范与安全战略措施研究

针对核与辐射事故防范与安全战略措施研究问题,介绍了中国核与辐射安全现状,分析了核安全,是国家安全的重要组成部分,为最大限度降低公众辐射受照水平,保护公众的身体健康与生活环境,要确保核的应用与辐射安全,中国已将核与辐射安全纳入国家安全的公共安全体系,并进行战略规划研究。本文通过分析中国核与辐射安全现状及发展趋势,提出了核与辐射事故防范和救治的发展目标,相对应的提出有关核与辐射事故防范与救治安全战略措施及建议。     

泡沫-细水雾对变压器油池火的冷却及热辐射阻隔特性研究

泡沫-细水雾在全尺寸变压器灭火实验中展现出高效灭火性能。纯水细水雾具有冷却效果好、热辐射阻隔能力强的特点,但添加泡沫灭火剂后对其冷却及热辐射阻隔特性的影响机制尚不明确。对泡沫-细水雾和纯水细水雾的冷却与热辐射阻隔特性进行了对比实验,并基于雾特性测试结果对相应性能的差异进行了分析。发现添加泡沫灭火剂后能降低水雾的粒径,从而令泡沫-细水雾的冷却和热辐射阻隔性能优于纯水细水雾。此外,泡沫灭火剂中的阻燃物质也是加速火焰熄灭的重要因素。研究结果可为变压器灭火系统选择、泡沫-细水雾系统工况参数优化等方面提供理论指导。     

中国省域碳排放强度的集聚效应和辐射效应研究

估算了中国1997—2013年30个省(市、自治区)的碳排放强度数据,并利用全局Moran's Ⅰ指数、局域Moran's Ⅰ指数以及莫兰散点图从集聚效应和辐射效应两个角度考察了我国区域碳排放强度空间分布特征.结果显示:1集聚效应:我国省域碳排放强度具有明显的空间集聚特征,碳排放强度水平相似区域倾向于相邻分布;另外,碳排放强度空间分布呈现不断优化的趋势,即"低-低"集聚不断增加,"高-高"集聚逐渐减少.2辐射效应:内蒙古、宁夏和山西等省对周边地区的碳排放强度具有明显的正向辐射效应,广东、福建和浙江等省对周边地区碳排放强度具有明显的负向辐射效应.最后,据此提出政策建议.     

辐射板强化喷管换热与红外抑制效果试验研究

试验研究了在发动机喷管中加装金属辐射板前后,喷管壁面温度、热喷流温度与喷管红外辐射特征的变化。结果表明,加装金属辐射板后,热喷流与喷管壁面之间的热量传递显著增强,热喷流中心温度降低,壁面温度明显升高,在90°方向上,热喷流3～5μm波段的红外辐射强度降低了38.5%。文中从热喷流、喷管壁面以及金属辐射板等相关部件的温度变化情况对红外辐射强度的变化原因进行了解释。      

紫外辐射对腐殖酸化学稳定性影响机制研究

腐殖酸广泛存在于各类地表水体中,分子结构对其物化性质有着显著影响.为探明紫外辐射过程对腐殖酸化学稳定性的影响途径,本研究采用光谱学和电化学技术考察了酚羟基和羧基等活性位点含量、胶体Zeta电位及其平均粒径等结构参数在辐射前后的变化特征.研究发现,未经辐射的水样,混凝过程对腐殖酸无明显去除效果.随着辐射时间的增加,腐殖酸的去除率大幅提高.照射3 h后,腐殖酸的去除率在80%以上.光谱分析结果表明,紫外辐射后腐殖酸分子中部分具有荧光效应的基团可能发生脱落或重排,但其芳香结构并未发生明显变化.胶体的Zeta电位和平均粒径均呈下降趋势,不利于腐殖酸的聚集沉淀;然而,腐殖酸分子中的羟基含量在辐射后略有下降,并伴随羧基和羰基等官能团的形成.活性位点数量及其反应活性的改善是腐殖酸化学稳定下降的主要原因.     

新疆某测井公司非密封放射源应用的辐射水平调查与评价研究

文章将非密封放射源^131 Ba的应用过程分为贮存、分装、运输及测井阶段,开展不同阶段放射性水平状况调查,对调查结果进行剂量估算与现状评价,掌握新疆某测井公司非密封放射源^131 Ba的应用过程对环境和人员造成的辐射危害。贮存、分装、运输及测井阶段的分阶段辐射环境影响评价方法的提出,为今后开展放射性同住素测井辐射环境影响评价提供方法借鉴。