Particulate air quality model predictions using prognostic vs. diagnostic meteorology in central California

Comparisons were made between three sets of meteorological fields used to support air quality predictions for the California Regional Particulate Air Quality Study (CRPAQS) winter episode from December 15, 2000 to January 6, 2001. The first set of fields was interpolated from observations using an objective analysis method. The second set of fields was generated using the WRF prognostic model without data assimilation. The third set of fields was generated using the WRF prognostic model with the four-dimensional data assimilation (FDDA) technique. The UCD/CIT air quality model was applied with each set of meteorological fields to predict the concentrations of airborne particulate matter and gaseous species in central California. The results show that the WRF model without data assimilation over-predicts surface wind speed by ～30% on average and consequently yields under-predictions for all PM and gaseous species except sulfate (S(VI)) and ozone(O₃). The WRF model with FDDA improves the agreement between predicted and observed wind and temperature values and consequently yields improved predictions for all PM and gaseous species. Overall, diagnostic meteorological fields produced more accurate air quality predictions than either version of the WRF prognostic fields during this episode. Population-weighted average PM_2.5 exposure is 40% higher using diagnostic meteorological fields compared to prognostic meteorological fields created without data assimilation. These results suggest diagnostic meteorological fields based on a dense measurement network are the preferred choice for air quality model studies during stagnant periods in locations with complex topography.     

灭菌预处理污泥及其滤液产氢发酵的比较研究

剩余污泥中的固态物质包含大量的蛋白质和多聚糖等有机质,一直被认为是一种具有潜力的生物制氢原料。灭菌预处理的剩余污泥会释放出大量的有机质,真空抽滤后去除掉污泥中固态物质得到滤液。将预处理污泥与滤液分别作为底物,接种产氢菌Pseudomonas sp. GZ1后产氢发酵。测定2种不同底物发酵反应过程中氢气的产量,以及底物的变化（SCOD、可溶性蛋白质、总糖、pH值）。实验结果表明,利用预处理后的污泥滤液作为底物能够有效提高氢气产量。滤液发酵的产氢量达到了4.44 mg H₂/g COD,比预处理污泥直接发酵提高了近3.3倍。本实验证明污泥中的固态物质在发酵过程中能释放出更多的营养物质,但实际上并不能被产氢菌有效地利用产生更多的氢气,并对其原因进行了探讨。     

一体式光催化－膜分离三相流化床反应器膜污染特性

通过利用颗粒状 TiO2催化剂(平均粒径0.258/μm)对酸性红 B 模拟废水的催化降解实验,对一体式光催化氧化-膜分离三相流化床反应器的膜污染特性进行了研究.结果表明,TiO2是造成膜污染的主要污染物,且 TiO2浓度愈大,膜污染愈严重;本实验体系TiO2的适宜浓度为 2g/L.反应区曝气量在 3.6m3/h 时膜污染最小;膜组件底部曝气装置可大大减轻膜污染,且其曝气量以 0.6 m3/h 为宜.表面冲洗、气体反冲洗和碱洗均可有效地清除膜表面和膜孔内的污染物,使膜通量恢复至90%以上;"表面冲洗 碱洗"和"表面冲洗 碱洗 气体反冲"可进一步提高膜通量的恢复,但不十分明显.     

国内外灾害数据信息共享现状研究

以互联网灾害数据库节点资料为基础,系统调研国内外已建成的40多个灾害数据库,从灾害数据库名称、数据尺度、灾害类型、维护机构、时间跨度、检索条件、数据来源、查询结果、收录标准等方面加以分类、对比,研究灾害数据信息共享建设现状.研究表明:国外尤其是发达国家灾害数据信息共享程度较高,灾害数据库建设较为规范;国内灾害数据信息共享在数据来源可靠性控制、收录数据标准界定、数据管理范式研究等方面有待改善.未来我国灾害数据共享建设应在对数据管理的体制、机制和法制等全面部署基础上,充分利用地理数据互操作技术、计算机网格技术、基于互联网的分布式地理信息、数据共享模式及基于Web Service的数据共享模式等新技术,以提高我国防灾减灾技术水平.     

基于层次分析和模糊数学的电解铝生产安全评价

影响电解铝生产安全状况的因素很多,相互之间具有不确定性和模糊性。建立电解铝生产安全模糊综合评价指标体系,运用层次分析法确定各指标权重,通过专家给出第3层次的模糊关系综合矩阵,对电解铝生产安全性进行模糊综合评价。     

Occurrence and distribution of triclosan in the German Bight (North Sea)

The potential of triclosan (TCS) acting as an endocrine disruptor has led to growing concern about the presence of TCS in the environment. In this study, seawater samples were collected from the German Bight during sampling campaigns conducted with the German research ships Gauss and Ludwig Prandtl. TCS was determined both in the dissolved phase and in the suspended particulate matters with concentrations ranging 0.8-6870 pg L⁻¹ and <1-95 pg L⁻¹, respectively. High concentrations of TCS were present in the estuaries of the Elbe and the Weser, indicating significant input of TCS by the river discharge. The correlation coefficient (R²) between the dissolved concentration and salinity was 0.79 for the data obtained from the Gauss cruise, showing an obvious declining trend from the coast to the open sea.     

水热条件下碳酰肼分解二噁英的研究

研究了保温温度为245、260℃水热条件下使用碳酰肼分解垃圾焚烧飞灰中二噁英的分解效果.结果表明,在高温水热条件下使用碳酰肼作为添加剂有利于二噁英的分解;在245、260℃下保温1 h,二噁英的分解率分别达到80%和90%以上,但二噁英毒性当量因2,3,7,8-TCDD的再生成减小很少,甚至增大;同时,在水热条件下,垃圾焚烧飞灰中的重金属取得了良好的稳定效果.     

几种阴阳离子对磷钨酸光催化降解甲基橙的影响

以磷钨酸为光催化剂,在紫外灯照射下,对甲基橙溶液进行光催化降解,考察了几种阴阳离子对磷钨酸光催化降解甲基橙溶液的影响。结果表明：Mg²⁺、Ca²⁺、NO^-₃、SO^2-₄和CO^2-₃均对催化活性有促进作用,其中Mg²⁺和Ca²⁺仅有微弱的促进作用;NO^-₃和SO^2-₄随着浓度的增加促进作用也有所增加;CO^2-₃则随着浓度的增加促进作用呈下降趋势;Mn²⁺、Al³⁺和Cl^-对光解反应存在较强的抑制作用,且Al³⁺和Cl^-随着其浓度的增加,抑制作用增强。     

钻井环境污染过程控制技术综述

钻井环境污染控制是实现清洁钻井的必要手段,文章介绍了钻井过程中的污染物和钻井作业环境污染控制措施,重点综述了钻井废水、废气、固体废物和噪声等环境污染控制技术。通过钻井环境污染过程控制将钻井作业对环境影响和危害的程度降至最低。     

生态环境脆弱地区油气田开发生态保护措施探讨

我国许多油气田处于生态环境脆弱地区,石油开采以及油气集输、储运等工程对生态环境的影响非常突出。文章依据生态保护的原则提出了油气田开发规划、设计、施工以及施工后几个阶段应当采取的生态保护措施,同时还提出了施工结束后的一些生态恢复措施,以供借鉴。