CaCl2高温热处理垃圾焚烧飞灰中重金属的挥发特性

以深圳市某垃圾焚烧厂飞灰为原料,采用高温管式电阻炉,研究了在0．6L／minN,气氛下,CaCl2在不同添加量、处理温度及处理时间下对飞灰中重金属Pb、Cd、Zn和Cu挥发特性的影响,并对收集到的二次飞灰进行成分及物相分析。结果显示,X射线衍射仪和EDS分析表明,二次飞灰主要是由NaCl、KCl和部分SiCl4组成,zn主要以K2ZnCl4形式挥发,而Pb则主要以氧化物PbO和Pb3SiO5的形式挥发。最终得到CaCl2热处理飞灰的最佳二次气化条件：以0．6L／minN,为载气,添加14wt％的CaCl2,在1100℃高温下处理2．5h。经CaCl2热处理后的剩余飞灰,其浸出毒性达到了《生活垃圾填埋场污染控制标准》要求。     

Trust in Citizen Science Research: A Case Study of the Groundwater Education Through Water Evaluation & Testing Program1

Thornton, Teresa and Jessica Leahy, 2012. Trust in Citizen Science Research: A Case Study of the Groundwater Education Through Water Evaluation & Testing Program. Journal of the American Water Resources Association (JAWRA) 48(5): 1032‐1040. DOI: 10.1111/j.1752‐1688.2012.00670.x Abstract: Data collected by citizen scientists, including K‐12 students, have been validated by the scientific community through quality assurance/quality control tests and publication of results in peer‐reviewed journal articles. However, if citizen science data are to be used by local communities, research is needed to determine which factors contribute to local community member trust in citizen science data, and how to increase the benefits and use of citizen science programs. This article describes the Groundwater Education Through Water Evaluation & Testing (GET WET!) program that employs middle and high school students, state and local government employees, environmental nongovernmental organization leaders, business representatives, college faculty and students, and other volunteers as citizen scientists to create a database of groundwater quality for use as a baseline for local water resources management. Data were gathered through semi‐structured interviews pre‐ and post‐involvement from 40 participants in this citizen science program conducted in five states in the northeastern United States. Results indicate that factors of trust are largely based on interpersonal trust and familiarity. We conclude with recommendations and future research that may improve local community member willingness to trust citizen science data generated by students.     

关于编制“十二五”环保规划的思考

围绕新形势下创建环保工作新道路这一主线,抓住十二五时期重大环境问题做了深刻思考,提出编制十二五环保规划应建立六个机制,即环境现状的评估机制、总量控制的扩项机制、污染减排的拓展机制、专项规划的环评机制、规划项目的筛选机制、规划执行力的保障机制,对基层工作具有借鉴作用。     

Stable isotope signatures reflect competitiveness between trees under changed CO2/O3 regimes

Here we synthesize key findings from a series of experiments to gain new insight on inter-plant competition between juvenile beech (Fagus sylvatica) and spruce (Picea abies) under the influence of increased O₃ and CO₂ concentrations. Competitiveness of plants was quantified and mechanistically interpreted as space-related resource investments and gains. Stable isotopes were addressed as temporal integrators of plant performance, such as photosynthesis and its relation to water use and nitrogen uptake. In the weaker competitor, beech, efficiency in space-related aboveground resource investment was decreased in competition with spruce and positively related to Δ¹³C, as well as stomatal conductance, but negatively related to δ¹⁸O. Likewise, our synthesis revealed that strong belowground competition for water in spruce was paralleled in this species by high N assimilation capacity. We suggest combining the time-integrative potential of stable isotopes with space-related investigations of competitiveness to accomplish mechanistic understanding of plant competition for resources.     

Tetrasomy 12p—unusual presentation in CVS

CVS direct preparations usually achieve limited resolution and are better at detecting numerical rather than structural abnormalities. A CVS direct preparation analyzed using G-banding revealed a 47,XY,+G karyotype in 5 of 11 cells and was reported as mosaic for trisomy 21. Subsequent analysis of the CVS culture found only normal male cells. Amniocentesis revealed both normal male cells and cells with an extra F-group chromosome. Fluorescence in situ hybridization (FISH) identified this chromosome to be an isochromosome from the short arm of chromosome 12 [i(12)(p10)]. The amniocyte karyotype was reported as 47,XY,+i(12)(p10)[12]/46,XY[8].ish i(12)(p10)(wcp12+), which is associated with Pallister–Killian syndrome. Reexamination of the CVS direct preparation by FISH with a chromosome 12 centromere probe confirmed the karyotype of this tissue to be 47,XY,+mar[5]/46,XY[6].nuc ish 12cen(D12Z3 × 3)/12cen(D12Z3 × 2). Thus, multiple studies, including amniocentesis and fluorescence in situ hybridization, may be required to fully and accurately evaluate abnormalities detected by CVS. This case also indicates that mosaicism for supernumerary isochromosomes may have a complex origin. Copyright © 2003 John Wiley & Sons, Ltd.     

A model of radiocesium cycling in a sand hills—Turkey Oak (Quercus laevis) ecosystem

Digital simulation models of radiocesium cycling in Turkey Oaks were developed from in situ ¹³⁴Cs tagging studies. Predictions of ¹³⁴Cs steady-state distribution for 3-, 4- and 5-compartment, donor-controlled models were compared with the estimated fallout ¹³⁷Cs distribution as a measure of model validation; output from the 5-compartment model compared best. Sensitivity analysis demonstrated that Turkey Oak burden of ¹³⁴Cs was equally sensitive to the output rate from the tree compartment and the availability of ¹³⁴Cs for uptake (i.e., presence in the root zone) but not the rate of uptake by Turkey Oaks. Observed distribution and model predictions indicate that radiocesium is readily bioaccumulated by Turkey Oaks (～13% of the ecosystem burden) from the soil and is cycled within the sand hills—Turkey Oak ecosystem.     

蚀坑等效为初始裂纹的疲劳寿命预测方法适用性分析

目的 分析将主导蚀坑等效成初始裂纹进行疲劳寿命预测的适用性。方法 选取LY12CZ航空铝合金试验件为研究对象,进行预腐蚀试验,对试样的腐蚀损伤情况进行观测和对比研究。应用ANSYS软件对不同腐蚀损伤情况的试验件进行有限元分析,分析试验件应力分布的变化。结果 随着腐蚀时间的延长,主导蚀坑附近区域其他点蚀坑的数量和尺寸呈上升趋势。以蚀坑间距离与蚀坑半径之比d/r为指标,d/r<4时,主导蚀坑处的应力分布受到其他蚀坑的影响较大,与试验结果相比,点蚀模型计算得到的疲劳寿命的平均相对误差为19.94%。d/r>4时,主导蚀坑处的应力集中系数基本恢复到单蚀坑时的大小,平均相对误差为3.74%。结论 d/r>4时,可以忽略其他蚀坑对主导蚀坑应力分布的影响,此时将主导蚀坑作为唯一疲劳源进行寿命计算是合理的。d/r<4时,主导蚀坑处的应力分布受到其他蚀坑的影响,此时将主导蚀坑作为唯一疲劳源进行寿命计算时将出现较大误差。     

两性修饰磁化炭对紫色土吸附菲的增强作用

为了验证两性修饰磁化炭材料对紫色土吸附菲的增强作用,采用共沉淀负载Fe_3O_4法和湿法有机负载分别制备了磁化炭(MC)和不同十二烷基二甲基甜菜碱(BS-12)修饰比例的两性修饰磁化炭(BS+MC),将其以1%的质量比加入到紫色土(PS)中,分别形成PS_(MC)和PS_(BS+MC)混合样品,批处理法研究各混合样品对菲的等温吸附和热力学特征,并对比了不同温度、离子强度和pH值对菲吸附的影响。结果表明:(1) MC和BS-MC材料的添加均增强了PS对菲的吸附能力,菲吸附量呈现PS_(200BS+MC)> PS_(150BS+MC)> PS_(100BS+MC)> PS_C> PS_(MC)> PS_(50BS+MC)> PS_(25BS+MC)> PS的趋势,PS_(BS+MC)对菲的吸附量随着添加材料上BS-12修饰比例的增加而增加。(2)菲在各供试土样上的吸附均表现为增温负效应(物理吸附),溶液pH值变化仅对PS_(150BS+MC)和PS_(200BS+MC)吸附菲有显著影响。离子强度增大不利于各供试土样对菲的吸附。(3) Henry模型适用于描述菲在供试土样上的等温吸附,且该过程呈现自发的、焓减和熵增的特征。从PS_C到PS_(MC)再到PS_(BS+MC),吸附过程呈现自发性、放热量和混乱度均增大的特征。