Assessing sensitivity of source term estimation

Source term estimation algorithms compute unknown atmospheric transport and dispersion modeling variables from concentration observations made by sensors in the field. Insufficient spatial and temporal resolution in the meteorological data as well as inherent uncertainty in the wind field data make source term estimation and the prediction of subsequent transport and dispersion extremely difficult. This work addresses the question: how many sensors are necessary in order to successfully estimate the source term and meteorological variables required for atmospheric transport and dispersion modeling?The source term estimation system presented here uses a robust optimization technique – a genetic algorithm (GA) – to find the combination of source location, source height, source strength, surface wind direction, surface wind speed, and time of release that produces a concentration field that best matches the sensor observations. The approach is validated using the Gaussian puff as the dispersion model in identical twin numerical experiments. The limits of the system are tested by incorporating additive and multiplicative noise into the synthetic data. The minimum requirements for data quantity and quality are determined by an extensive grid sensitivity analysis. Finally, a metric is developed for quantifying the minimum number of sensors necessary to accurately estimate the source term and to obtain the relevant wind information.     

Biosorption and degradation of decabromodiphenyl ether by <Emphasis Type="Italic">Brevibacillus brevis</Emphasis> and the influence of decabromodiphenyl ether on cellular metabolic responses

There is global concern about the effects of decabromodiphenyl ether (BDE209) on environmental and public health. The molecular properties, biosorption, degradation, accumulation, and cellular metabolic effects of BDE209 were investigated in this study to identify the mechanisms involved in the aerobic biodegradation of BDE209. BDE209 is initially absorbed by wall teichoic acid and N-acetylglucosamine side chains in peptidoglycan, and then, BDE209 is transported and debrominated through three pathways, giving tri-, hepta-, octa-, and nona-bromodiphenyl ethers. The C–C bond energies decrease as the number of bromine atoms on the diphenyl decreases. Polybrominated diphenyl ethers (PBDEs) inhibit protein expression or accelerate protein degradation and increase membrane permeability and the release of Cl^?, Na⁺, NH₄ ⁺, arabinose, proteins, acetic acid, and oxalic acid. However, PBDEs increase the amounts of K⁺, Mg²⁺, PO₄ ^3?, SO₄ ^2?, and NO₃ ^? assimilated. The biosorption, degradation, accumulation, and removal efficiencies when Brevibacillus brevis (1 g L^?1) was exposed to BDE209 (0.5 mg L^?1) for 7 days were 7.4, 69.5, 16.3, and 94.6 %, respectively.     

富含活性氯与Al13水处理药剂对铜氰络合物去除效能

含重金属铜离子与氰离子（CN）的络合物广泛存在于电镀、冶金等工业废水中,是一种较难处理的污染物。富含活性氯和Al13聚合体的水处理药剂（PACC）兼具氧化和絮凝效能,在处理含重金属氰络合物（[Cu（CN）3]2-）废水方面具有良好的应用前景。研究PACC与[Cu（CN）3]2-的反应计量学、动力学,考察了pH、反应时间和投药量等影响因素,确定PACC的最佳工作参数。结果表明,PACC可同时实现对CN的氧化和对Cu2＋的絮凝,有效去除水中[cu（CN）3]2-使用PACC对[Cu（CN）3]2-的无害化处置过程分为2个阶段：CN-首先被氧化成氰酸根（OCN）;然后OCN-被进一步氧化并生成碳酸氢根和氮气,同时所释放的游离态铜离子被絮凝去除。这2个阶段反应的最佳pH分别为11和8,去除1tool[Cu（CN）3]2-的最佳投药量为9．35molCl2的PACC;在此条件下反应43min后,其出水中CN-和Cu2＋的浓度均达到排放标准（GB21900—2008）要求。     

A two-step approach for relating tapered element oscillating microbalance and dichotomous air sampler PM2.5 measurements

A method for transforming continuous monitoring (CM) fine particulate matter (aerodynamic diameter <2.5 μm; PM_2.5) data (i.e., by tapered element oscillating microbalance [TEOM]) obtained from the Canadian National Air Pollution Surveillance (NAPS) program to meet the data quality objective (DQO) of R² > 0.8 against the co-located federal reference method (i.e., dichotomous air sampler) is described. By using a two-step linear regression to account for the effect of the ambient temperature, 16 out of the 23 examined sites met the common model adequacy threshold of R² > 0.8. After the transformation, 20 out of the 23 examined sites met the DQO of R² > 0.7, as recommended by the U.S. Environmental Protection Agency (EPA). A combined two-step statistical approach was also examined and revealed similar results. The methods described herein show that the CM data can be successfully transformed to meet DQOs for representative sites across Canada using year-round (both summer and winter) data.

Implications:This study provides a transformation approach to correct ambient TEOM data against the federal reference method without dividing the ambient data according to warm and cold seasons. This transformation approach will significantly improve the correlation coefficient between TEOM and dichotomous air sampler data. It is possible that TEOM data at many Canadian locations can be transformed to meet the EPA data quality objective, thus making this transformation approach useful for comparisons of ambient PM data across jurisdictions.     

燃煤飞灰颗粒物中元素分布规律的研究

利用ICP-AES光谱仪和TOC总碳分析仪对不同粒级下的飞灰颗粒进行了元素测定,对元素分布规律的形成原因进行了分析.分析结果表明:煤经旋流燃烧器燃烧而未经过除尘设备的飞灰中300目以下小颗粒含量较高.随着燃烧温度的升高,大颗粒的含碳量增加,小颗粒的含碳量减少,元素Al、Mg、Cr在各个粒级中含量变化不大,Ti、Ba、V在大于280目的小颗粒中含量有下降趋势,其他大部分痕量元素在大于300目的小颗粒中得到富集.     

燃煤飞灰中痕量元素的研究

综述了煤中痕量元素的含量分布、煤燃烧过程中痕量元素的分布转化规律,总结了痕量元素在飞灰中的富集规律和赋存状态,以及痕量元素的释放控制方法和技术,并探讨了今后的研究方向.     

外来植物入侵力主要理论与展望

外来植物入侵是全球性环境问题.我国植物入侵态势严峻,随着全球化的提速,这一威胁将加剧.总结外来种入侵力的主要理论,分析其生态学机制、常见的理解误区,剖析入侵力的主要表现形式和产生的机制,可为进一步明确未来研究方向,提高预测、预警、预防和治理工作效率提供参考.通过总结分析发现:理论间存在部分包含、支持、相悖等逻辑关系,并...     

鄱阳湖生态经济区土地生态安全警情研究

土地生态安全研究是当前土地可持续利用研究的前沿课题。为了确保土地生态安全,就必须对土地生态安全系统预警进行研究。结合预警理论,从压力 状态 社会响应3方面构建了土地生态安全预警指标体系,运用物元模型对鄱阳湖生态经济区2001~ 2008年的土地生态安全的警情进行分析。结果显示：2001年鄱阳湖生态经济区土地生态安全警情为轻警状态;2002~ 2004年处于中警状态;2005~ 2006年下降为重警状态;2007~ 2008年土地生态安全警情状况有所好转,处于中警状态。通过研究表明,利用物元模型进行区域土地生态安全预警研究是可行的,具有计算简便、意义明确、评价精度高等优点,可为土地生态安全预警研究提供了另一种途径     

新一代环保型燃料——水煤浆

本文通过水煤浆在工业锅炉、电站锅炉及窑炉上的燃烧应用,说明水煤浆是新型清洁环保燃料。     

论竞技武术套路新规则及动作的创新

本文运用文献资料、调查访问等方法,对竞技武术套路新旧竞赛规则进行对比,并分析探讨新规则的实施对武术套路训练的影响,提出对此所应采取的训练方法和策略,同时对竞技武术套路动作创新的科学性、新颖性、针对性、技击、美学等原则与难度递进法、组合法、象形法等方法进行了论述,以拓宽武术动作创新的思路,为竞技武术套路动作的创新提供理论依据。