Size fractionation of organic matter and heavy metals in raw and treated leachate

This study characterized the organic matter and heavy metals in the leachate from two typical municipal solid waste (MSW) sanitary landfills in China, the recently established (3-year-old) Liulitun landfill and the mature (11-year-old) Beishenshu landfill, using a size fractionation procedure. The organic matter of all raw and treated leachate samples primarily existed in a truly-dissolved fraction with an apparent molecular weight (AMW) of <1 kDa, and its percentage decreased with an increase in overall AMW. The leachate from the newer landfill had a higher percentage of truly-dissolved organic matter. After anaerobic treatment, this leachate had a similar size fraction of organic matter to that seen for the raw leachate of the mature landfill. Biochemical processes had different removal efficiencies for various types of AMW organic matter, and the concentration of moderate AMW organic matter appeared to increase throughout these processes. Most of the heavy metals existed in a colloidal fraction (AMW >1 kDa and particle size <0.45 μm). The behaviors of different species of heavy metals had large variations. The size fractions of heavy metal species were significantly affected by treatment processes and landfill age, except for Zn. The concentration ratio of heavy metals to organic matter was maximal in the colloidal fraction and showed an inverse change to that seen for organic matter concentration changes caused by biochemical processes. Consequently, the pollution levels of heavy metals were substantially increased by treatment processes, although their concentrations decreased.     

Comparison among filter-based,impactor-based and continuous techniques for measuring atmospheric fine sulfate and nitrate

Filter-based methods for sampling aerosols are subject to great uncertainty if the gas–particle interactions on filter substrates are not properly handled. Sampling artifacts depend on both meteorological conditions and the chemical mix of the atmosphere. Despite numerous of studies on the subject, very few have evaluated filter-based methods in the Asian environments. This paper reports the results of a comparison of the performances of two filter-based samplers, including a Thermo Anderson Chemical Speciation Monitor (RAAS) and a honeycomb denuder filter-pack system, a Micro Orifice Uniform Deposit Impactor (MOUDI) and a real-time ambient ion monitor (AIM, URG9000B) in measuring atmospheric concentrations of PM_2.5 sulfate and nitrate. Field studies were conducted at an urban site in Jinan, Shandong province, during the winter of 2007 and at a rural site near Beijing in the summer of 2008. The AIM was first compared with the honeycomb denuder filter-pack system which was considered to have minimal sampling artifacts. After some modifications made to it, the AIM showed good performance for both sulfate and nitrate measurement at the two sites and was then used to evaluate other instruments. For the un-denuded RAAS, the extent of sampling artifacts for nitrate on quartz filters was negligible, while that on Teflon filters was also minimal at high nitrate concentrations (>10 μgm^?3); however, loss through evaporation was significant (～75%) at low nitrate concentrations under hot summer conditions. The MOUDI using aluminum substrates suffered a significant loss of nitrate (50–70%) under summer conditions due to evaporation. Considering that the aluminum substrates are still being widely used to obtain size-resolved aerosol compositions because of their low cost and accurate mass weighed, caution should be taken about the potential significant under determination of semi-volatile components such as ammonium nitrate.     

Atmospheric emission of polychlorinated biphenyls from multiple industrial thermal processes

In this study, field measurements were conducted to estimate and characterize the atmospheric emission levels and profiles of polychlorinated biphenyls (PCBs) from multiple industrial thermal processes. The emission levels and profiles of PCBs from five types of thermal processes at twenty-three plants were studied and compared with eight processes reported in our previous studies. Correlation analysis was preformed to identify a marker congener for emission of ΣPCB. A significant correlation was observed between congener CB-118 and ΣPCB (R² = 0.65 and p < 0.01), which suggests that CB-118 is a good marker congener for emission of ΣPCB. The profiles of PCBs emitted from the thirteen thermal processes were compared, and this information could be used for studying source–receptor relationships and identifying the specific sources of PCBs. To prioritize the sources for control, the concentrations of PCBs from thirteen industrial thermal sources were compared. The PCB concentrations from secondary zinc smelting and thermal wire reclamation were about one to three order magnitude higher than those of other sources, which suggests that these two sources be given priority in PCB source control. Finally, the atmospheric emission factors of PCBs from the thirteen industrial sources were summarized, and these data will be useful for developing an integrated emission inventory of PCBs.     

An inexact-stochastic with recourse model for developing regional economic-ecological sustainability under uncertainty

Effective planning of resources management is important for facilitating socio-economic development and eco-environmental sustainability. Such a planning effort is complicated with a variety of uncertain, dynamic and nonlinear factors as well as their interactions. In this study, an inexact-stochastic quadratic programming with recourse (ISQP-R) method is developed for reflecting dynamics of system uncertainties based on a complete set of scenarios as well as tackling nonlinearities in the objective function to reflect the effects of marginal utility on system benefits and costs. Moreover, since penalties are exercised with recourse against any infeasibility, the ISQP-R can support the analysis of various policy scenarios that are associated with different levels of economic consequences when the promised targets are violated. The developed method is applied to a case study of planning resources management and developing regional ecological sustainability. The results have been generated and are helpful for decision makers in not only identifying desired resources-allocation strategies but also gaining insight into the tradeoff between economic objective and eco-environment violation risk.     

浅谈雷电流效应在雷电防护设计中的应用

对雷电流在雷击点和雷电流流经金属体阶段的热效应和机械效应进行计算分析,重点计算分析各金属材料截面积对导体温升的影响。计算在雷击点雷电流对铝、钢、铜等金属材料的熔化破坏效应,指出雷电流的温升效应对金属结构自身不具备伤害性且可逆;而雷电流在雷击点对金属体会有明显的熔化破坏效应,故具有承重、受力等结构力学性质的金属构件不适合作为接闪器直接承受雷击。对雷击的电磁感应效应进行实例分析,说明其在电子信息系统电磁屏蔽中的应用。     

Efficient degradation of drug ibuprofen through catalytic activation of peroxymonosulfate by Fe3C embedded on carbon

Ibuprofen(IBU),a nonsteroidal anti-inflammatory drug,is becoming an important member of pharmaceuticals and personal care products(PPCPs)as emerging pollutants.To degrade IBU,magnetic Fe_3C nanoparticles embedded on N-doped carbon(Fe_3C/NC)were prepared as a catalyst by a sol–gel combustion method.As characterized,the Fe_3C/NC nanoparticles were composed of a NC nano-sheet and capsulated Fe_3C particles on the sheet.The Fe_3C/NC nanoparticles were confirmed an efficient catalyst for peroxymonosulfate(PMS)activation to generate sulfate radicals(SO_4~(·-)),single oxygen(~1O_2)and hydroxyl radicals(·OH)toward the degradation of IBU.The added IBU(10 mg/L)was almost completely removed in 30 min by using 0.1 g/L Fe_3C/NC and 2 g/L PMS.The catalyst was confirmed to have good ability and excellent reusability through leaching measurements and cycle experiments.A catalytic mechanism was proposed for the catalytic activation of PMS on Fe_3C/NC,which involves both Fe_3C reactive sites and N-doped carbon matrix as reactive sites in Fe_3C/NC.Moreover,the degradation pathway of IBU in the Fe_3C/NC-PMS system was proposed according to the detections of degradation intermediates.     

建筑物震害的类比预测方法研究

在“同一场地上相似的两幢建筑物,未来具有相似的震害程度”的假设前提下,提出了如何利用一个地区的部分建筑物单体的震害预测结果,对这一地区的其它建筑物单体的震害进行预测的方法,并从结构抗震角度研究了如何用加权Ｈａｍ－ｍｉｎｇ距离度量两幢建筑物的相似程度。     

全球和中国变暖特征及未来趋势

自小冰期在上世纪末结束以来，全球气温波动上升，至本世纪８０年代全球平均上升了０．４５±０．１５℃。２０～３０年代的强烈升温（＞０．３℃）归因于自然回暖，６０年代至７０年代初出现北半球为主的一度降温，８０年代又强烈升温至今未息，这次升温以冬季和夜间变暖为主，高纬度地区又大于中低纬度地区，可认为是人为的ＣＯ２等温室气体增加起了重要作用。中国２０～３０年代升温，６０年代降温和８０年代北部地区升温均大于全球平均值。全球降水变化远比温度变化复杂，总趋势略有上升，中国基本处在中纬度降水减少带中，呈现暖干化趋势。在２０年代和６０年代有两次变旱的气候跃变，相伴着旱灾的加重，但降水变率很大，洪涝灾害更为严重。未来气候主要取决于ＣＯ２及其它微量气体增加所加犟的温度效应，全球继续并持久变暖。根据政府间气候变化委员会（ＩＰＣＣ）预测的下世纪温室气体排放，Ｈｕｌｍｅ等（１９９２）综合新近若干模式研究结果，预期全球平均升温最佳估计值到２０５０年为１．２℃（低限与高限范围为０．８℃和１．８℃），而到２１００年为２．５℃（变化范围１．６～３．８℃），中国到２０５０年升温值在东部和东南部为１．０～１．５℃，在东北、华北和西部为１．５～２     

人类住区可持续发展

改善人居环境，是经济和社会发展中必须重视的一个问题。本文以人类住区发展为出发点，分析了我国人居环境的现状和住区发展面临的问题，指出改善人类住区环境，实现可持续发展，需要走一条科技、经济、社会和人口、资源、环境协调行动的可持续发展的道路。