华北南部重污染城市周边区域二次气溶胶的化学特征及来源解析

为探究华北南部地区重污染城市邯郸市北部地区冬季大气颗粒物的化学组分及来源,于2020年11月23日至12月12日采集了 PM1 和PM2.5样品并进行了分析.观测期间日平均ρ(PM1)和ρ(PM2.5)分别为114.53 μg·m-3和124.25μg·m-3,PM1/PM2.5比值的变化范围为83.3％～95.3％,...     

Assessment of New Vehicles Emissions Certification Standards in the Metropolitan Area of Mexico City

Light duty gasoline vehicles account for most of CO hydrocarbons and NOx emissions at the Metropolitan Area of Mexico City (MAMC). In order to ameliorate air pollution from the beginning of 2001, Tier 1 emission standards became mandatory for all new model year sold in the country. Car manufacturers in Mexico do not guarantee the performance of their exhaust emissions systems for a given mileage. The purpose of this study was to assess whether the Tier 1 vehicles will stand the certification values for at least 162000 km with the regular fuel available at the MAMC. Mileage accumulation and deterioration show that certified carbon monoxide emissions will stand for the useful life of the vehicles but in the case of non-methane hydrocarbons will be shorter by 40%, and nitrogen oxides emissions above the standard will be reached at one third of the accumulated kilometers. The effect of gasoline sulfur content, on the current in use Tier 1 vehicles of the MAMC and the impact on the emissions inventory in year 2010 showed that 31000 extra tons of NOx could be added to the inventory caused by the failure of the vehicles to control this pollutant at the useful life of vehicles.     

微生物絮凝剂产生菌的筛选及其絮凝特性

采用常规的微生物学方法,从垃圾渗滤液中筛选到一株高效微生物絮凝剂产生菌LB1,根据其形态学和生理生化特征初步鉴定该菌株属于假单胞菌属,命名为Pseudonomas sp. LB1。LB1所产微生物絮凝剂的絮凝特性的研究结果表明,LB1的最佳产絮凝时间为96 h,所产絮凝活性物质主要是其生长过程中的胞外分泌物和细胞生长后期的次级代谢产物,菌体细胞本身具有一定的助凝作用。LB1所产絮凝剂最佳加样量为3％（体积分数V/V）;对pH的适应范围较宽,在4～10之间具有较高的絮凝活性,均大于75％;温度为25℃时絮凝率为86.3％,在25～60℃之间,絮凝率基本保持稳定;LB1所产絮凝剂对几种废水具有较好的絮凝效果。     

灰色Elman神经网络在火灾事故预测中的应用研究

针对我国火灾事故现状,结合灰色理论和神经网络的特点,提出灰色Elman神经网络火灾事故预测模型。依据我国1998—2007年火灾事故统计数据,分别选用GM(1,1)模型和灰色Elman神经网络模型对1998—2005年数据(火灾起数)进行拟合,对2006年、2007年数据进行(火灾起数)预测。结果表明:灰色Elman神经网络火灾事故预测模型符合火灾事故的特点;有效地解决了传统灰色预测模型在火灾事故预测中误差大稳定性差的缺陷,提高了预测精度;可对火灾事故进行预测与分析,为消防安全管理提供依据,以最大限度地减少火灾事故的发生。     

HDNPTT与镉显色反应的研究

应用合成的新试剂 1- (2 -羟基 - 3 ,5 -二硝基苯 ) - 3 - (4 -苯基 - 2 -噻唑 ) -三氮烯 (HDNPTT) ,研究了在表面活性剂TritonX - 10 0存在下 ,它与Cd2 的显色反应。结果表明 ,在 pH 8 0～ 10 0范围内 ,Cd2 与该试剂形成的配合物 ,其最大吸收峰位于 5 35nm处 ,摩尔吸光系数为 1 89× 10 5L·mol-1·cm-1。Cd2 在 0mg/L～ 0 32mg/L范围内符合比尔定律。此法用于环境水样和人发样品中微量镉的测定 ,结果满意。     

基于灰色BP网络的火灾事故预测

将BP网络模型与灰色系统预测方法相结合,利用人工神经网络对GM(1,1)模型进行残差修正,建立了火灾事故预测模型.该模型兼具灰色系统与BP网络的优点,不但能体现火灾复杂的灰色系统行为,又能根据每次学习误差的不同调整学习速率,加快收敛速度.与单一的GM(1,1)模型相比,该模型预测结果具有更高的精度.     

公共聚集场所防火设计中的火灾场景设计研究

在对公共聚集场所性能化防火设计的基础上,介绍火灾场景设计的内容和方法,通过对火灾荷载和火灾热释放速率的计算,得到火灾发展的变化情况和热释放速率曲线,进而构建适合公共聚集场所等大空间建筑的火灾设定模型。并应用该计算方法和模型对某超市进行火灾场景设定来确定该火灾场景的最大热释放速率,并对其火灾蔓延可能性进行讨论,为火灾危害性评估以及火灾探测和扑救系统的有效性评估提供依据。     

硫化矿石堆自燃的灰色预测研究

采用灰色预测模型GM(1,1)对硫化矿石堆的自燃进行预测.根据相同间隔时间的矿石温度,通过灰色计算得出下一个或以后几个时间段的温度,将预测的温度与已有试验数据进行比较;参照硫化矿的发火周期,预测几天后矿石堆的自热状态,从而指导工作人员采取相应的防、灭火措施.实例验证表明,GM(1,1)适用于硫化矿的自燃预测.本研究对矿山安全建设工作具有一定的参考价值.     

Indoor Air Quality at Rural and Urban Sites in Pakistan

In the developing world, the vast majority of people rely on solid biomass fuels for cooking and heating which results in poor indoor air quality. The present study determined indoor air quality in some rural and urban areas of Pakistan. Measurements were made of particulate mass (PM10, PM2.5 and PM1), number concentration and bioaerosols in different micro environments. PM10 concentrations of up to 8,555 μg/m³ were observed inside the kitchens where biofuels were used as energy source. Cleaning and smoking was identified as a major source of indoor particulate pollution and concentrations of more than more than 2,000 μg/m³ were recorded in the living room during these activities. Indoor number concentrations in Lahore were typically greater than those observed outdoors in European cites. At a rural site the highest Colony Forming Units (CFUs) were in the 0.5 μm–2 μm size fraction, while at the urban location CFUs were dominant for 2 μm–16 μm. It was observed that CFUs(Colony Forming Units) counts were higher inside living rooms than kitchens. It is important to note that women and children were exposed to extremely high levels of particulates during cooking. Overall, indoor air quality in Pakistan was poor and there is a dire need to take a serious step to combat with it.     

降解甲基叔丁基醚的PM1生物膜培养及性能研究

在pH值7.2～8.5、温度25℃、DO≥5 mg/L的条件下,用含有甲基叔丁基醚（MTBE）的模拟废水对Methylibium petroleiphilum PM1进行富集培养并在陶粒表面挂膜,进而对其特性、性能等进行了研究。填料表面生物膜MTBE降解的序批实验和电镜照片分析均表明陶粒表面已成功附着PM1高效降解菌形成的生物膜。在挂膜后期,当起始MTBE浓度为100～110 mg/L时,经过24 h,MTBE的去除率达到65%以上并基本稳定,其中挥发占4.6%,生物降解起主导的作用。