Emission of volatile organic compounds (VOC) from tropical plant species in India

Foliar emission of volatile organic compounds (VOC) from common Indian plant species was measured. Dynamic flow enclosure technique was used and the gas samples were collected onto Tenax-GC/Carboseive cartridges. The Tenax-GC/Carboseive cartridges were attached to the thermal disorber sample injection system and the gas sample was analysed using gas chromatography (GC) with flame ionisation detection (FID). Fifty-one local plant species were screened, out of which 36 species were found to emit VOC (4 high emitter; 28 moderate emitter; and 4 low-emitter), while in the remaining 15 species no VOC emission was detected or the levels of emission were below detection limit (BDL). VOC emission was found to vary from one species to another. There was a marked seasonal and diurnal variation in VOC emission. The minimum and maximum VOC emission values were < 0.1 and 87 microgg(-1) dry leaf h(-1) in Ficus infectoria and Lantana camara respectively. Out of the 51 plant species studied, 13 species are reported here for the first time. Among the nine tree species (which were selected for detailed study), the highest average hourly emission (9.69+/-8.39 microgg(-1) dry leaf) was observed in Eucalyptus species and the minimum in Syzygium jambolanum (1.89+/-2.48 microgg(-1) dry leaf). An attempt has been made to compare VOC emission from different plant species between present study and the literature (tropical and other regions).     

Climate change and changes in global precipitation patterns: what do we know?

The objective of this paper is to synthesize the large literature recording changing patterns of precipitation in the observed data, thus indicating that climate change is already a reality. Such a synthesis is required not only for environmental researchers but also for policy makers. The key question is the broad picture at major regional and continental levels. Some interesting conclusions for this survey are emerging. For example, the review shows increased variance of precipitation everywhere. Consistent with this finding, we observe that wet areas become wetter, and dry and arid areas become more so. In addition, the following general changing pattern is emerging: (a) increased precipitation in high latitudes (Northern Hemisphere); (b) reductions in precipitation in China, Australia and the Small Island States in the Pacific; and (c) increased variance in equatorial regions. The changes in the major ocean currents also appear to be affecting precipitation patterns. For example, increased intensity and frequency of El Ni?o and ENSO seem associated with evidence of an observed "dipole" pattern affecting Africa and Asia, although this time series is too short so far. But the changing pattern calls for renewed efforts at adaptation to climate change, as the changing precipitation pattern will also affect the regional availability of food supply.     

非煤矿山地下开挖工程安全等级评定方法研究

非煤矿山地下工程开挖中经常发生意外伤亡事故,对其安全性评价尚缺较好的方法。笔者借鉴类似行业的评价方法并结合多年地下工程安全经验,综合应用国内外岩体力学研究和测试的成果,建立了针对非煤矿山地下开挖工程的安全分级体系。以“火灾、爆炸危险指数评价法”(DOW法)和岩体工程分类法为建立模型的基础,根据影响地下开挖工程主要因素及其权重分析,导出了具有针对性的危险性的评价指数,并据此将工程分为Ⅰ~Ⅴ五个安全等级。以该方法对白银公司小铁山矿高分段胶结充填采矿法某试验采场的安全性进行分级,其结果和施工实际较为接近,说明分级方法有一定普适性。     

基于贝叶斯网络的一种事故分析模型

贝叶斯网络被认为是人工智能研究中不确定性知识表示和推理的重要工具。当前在系统安全领域中已开始运用贝叶斯网络技术进行故障诊断分析，然而故障只是诱发事故的因素之一，无法系统的评价事故背后的隐患，对事故后果的预测也甚少涉及。笔者将贝叶斯网络作为一种事故分析手段，在事故致因理论的基础上提出了一种基于危险因素-事故-事故危害的三层贝叶斯网络拓扑模型；阐述了网络模型层次间的因果关联关系、各层次的构成、节点的描述方法以及网络模型的构建方法；最后通过一个天然气球罐的分析案例验证了该模型分析方法的可行性和有效性。     

公路交通事故危险性与事故原因的灰色关联分析

交通安全既可以采用交通事故次数来评价，也可以根据交通事故的严重度进行衡量。不同的交通事故诱因，其事故后果的危险程度也不一致。运用灰色系统理论，以某段道路上交通事故多发点的“地点危险指数”为参考数列，以这些地点的不同事故诱因为比较数列，对“事故危险指数”和引发交通事故的各类事故原因之间作灰色关联分析，可以找出该路段上危害性最大的一些交通事故成因，在交通管理和交通安全宣传教育中有针对性地进行防治。本文以107国道1716—1883公里的交通事故数据为例给出了算例。     

煤矿火灾过程仿真模拟系统的研究

以煤矿火灾理论和仿真模拟理论为基础，建立了描述煤矿火灾烟流扩散和风流状态的数学模型。运用面向对象技术和三维虚拟现实技术，开发了煤矿火灾过程三维动态仿真模拟系统。该系统通过逼真、形象的三维可视化，模拟火灾发展趋势，实现了火灾数值模拟与灾害现象真实描述的有机结合，为煤矿火灾影响范围和危害程度的预测提供了切实可靠的决策依据。     

夹涤草堂旅游风景区资源开发与规划设计

在分析夹潦草堂旅游风景区背景要素和制约因素的基础上，遵循史学文化、知识、淳真自然的三大设计理念，采用圈层递进的总体布局构思，设计了7个主题区域的空间布局，开发出修学旅游、观光旅游、度假旅游、森林探险旅游等四大主导旅游产品。     

采煤沉陷对生态环境的影响及其修复措施——以邹城矿区为例

采煤沉陷区生态环境形势严峻，土地复垦势在必行。分析了采煤沉陷对邹城矿区生态环境的影响，并提出了疏干法、就地平整法、挖深垫浅法等实际的土地生态修复措施。     

微波处理造纸黑液滤渣及其开发与利用

利用微波处理酸析混凝沉淀法产生的造纸黑液滤渣，制成多孔状炭直接应用于造纸黑液的脱色，经脱色的溶液比原沉淀分离后的上清液脱色率提高38．5％，比市售活性炭脱色效果提高11．0％，比未加气孔引发剂微波烧制的炭脱色率提高3．5％。结果表明，采用微波处理造纸黑液滤渣制成的炭有明显的脱色效果，同时避免了造纸黑液滤渣对环境的二次污染。     

Prenatal diagnosis of Niemann–Pick diseases types A,B and C

Prenatal diagnosis of Niemann–Pick disease types A and B is routinely accomplished by sphingomyelinase assay. For Niemann–Pick type C disease, demonstration of an abnormal intracellular cholesterol trafficking is a complex procedure, and mutational analysis (NPC1 or NPC2/HE1 gene), whenever feasible, represents a major advance. Copyright © 2002 John Wiley & Sons, Ltd.