Seasonal and spatial character of PCBs in a chemical industrial zone of Shanghai,China

As one of China’s great metropolises, Shanghai is suffering from the impact of manufacture and the use of chemical industrial products, and it faces serious pollution from polychlorinated biphenyls (PCBs). Therefore, in this study, in order to assess the seasonal and spatial character of contamination from chemical industrial zones, the concentrations of PCBs have been measured in various environmental media, including soil, leaves, and atmospheric particulate samples collected in a chemical industrial zone of Shanghai and compared with samples from presumably unpolluted sites of rural areas. In soils, the PCB concentrations ranged from 0.5 ng g⁻¹ (unpolluted site) to 586.85 ng g⁻¹ (chlor-alkali industry site). The concentrations of PCBs in evergreen leaves ranged from 0.3 ng g⁻¹ to 32.46 ng g⁻¹, and more chlorinated biphenyls congeners, such as penta-biphenyls and hexa-biphenyls, were the dominant contributors in winter and spring. Seasonal differences and the constitution patterns of congeners might be affected by the temperature and industrial activities. The PCB concentrations in the leaves of deciduous trees increase over time as the leaves grow. The PCB concentration in atmospheric particulates was in the range of 9.22–14.15 × 10³ pg m⁻³, which might be the result of influence from climate and industrial activities. The relativity of PCB contents among the environmental media was discussed. The results in this paper provide an important profile of the current contamination status of a key chemical industrial zone in China.     

Revisit to community forest in northeast of Thailand: changes in status and utilization

The International Forest Resources and Institutions (IFRI) research program is designed by a network of social and natural scientists from different parts of the world and is intended to exam the interdependency relations between people and forests and to analyze forest conditions In 2003, in terms of IFRI methodology, our team has done some relative research in Kog Bung Preu community forest, which locates in the northeast of Thailand, and collected forest data including some key variables and parameters, such as DBH (Diameter at Breast Height), HEIGHT, BA (Basal Area), and DENSITY of trees and saplings in 31 plots in this community forest. In 2009, we re-visited the forests and 31 forest plots, using IFRI methodology and GPS technology again to collect data based on four key variables of trees and saplings. In the process of data management and analysis, we use IFRI Data Entry Application, and Access, Excel, SPSS, Map-source etc. to help us manage and analyze collected data. Meanwhile, a variety of qualitative and quantitative techniques were used to understand and analyze different variables and data. This paper will mainly focus on the changes in the Kog Bung Preu forest since last visit. By comparing and analyzing the forest plot data of two visits by using macro- and micro-scale, it is intended to reveal the actual status of Kog Bung Preu forest and to discuss the reasons behind the changes. From fieldwork and investigation in 31 forest plots and community residents again, we found that for saplings, DHB has slightly increased, however it did not test as significantly different, unlike HEIGHT which had also increased and had significant differences between the 2 years. Density and basal area for sapling revealed the same trend. They appeared to be notably decreasing from 2003 to 2009. BA does not prove to be significantly different, but DENSITY has a significant difference. Comparing tree variables between 2003 and 2009 gave different results. Every variable showed an increase from the previously recorded data. However, only the DBH and HEIGHT of trees demonstrated significant differences between the 2 years. The generally declining rate of sapling density and basal area may be related to the increase in the density and basal area of trees. It may be assumed that within the 6-year period, some saplings in the plots matured and now fall into the tree class. During this study, a total of 78 species in 38 families were recorded; 51 species are trees belonging to 22 families, 25 species from 14 families are saplings, 12 species from 9 families are seedlings, 2 woody climber species were recorded from 1 family; and herbs and grasses consisting of 27 Species from 16 families. Species composition has decreased compared to data recorded in 2003 from 97 to 78 species in 2009 as well as families which had higher recorded counts in 2003 (48 families) but lower recorded counts in 2009 (38 families). The socioeconomic situation of local community has some changes, from interview we found that most of changes focus on the collection of forest products and timber uses. The interaction between forest and people has improved. Finally, based on the analysis earlier, we discussed some aspects and provide relative suggestions.     

湿法烟气脱硫技术的比较与选择

本文综合评述几种典型的烟气脱硫技术,比较各种烟气脱硫技术的特点和应用经济性,并分析了钙法脱硫技术和镁法脱硫技术实际应用的情况。结果表明在当前众多的烟气脱硫技术中,镁法烟气脱硫技术经济、脱硫效率高、污染少、无二次污染,必将成为今后烟气脱硫技术发展的主要趋势。     

轮毂行业涂装车间环境污染与防治

轮毂行业快速增长的同时,涂装车间作业排放的废气、废水、废渣、噪声,对环境造成了严重的污染。分析了轮毂行业涂装车间的环境污染状况,包括污染物的来源和种类,指出采用低污染材料、先进的生产设备,并优化生产工艺,是解决涂装“三废”问题的有效途径。     

基于水质模型的水污染物排污权交易理论研究

在中国排污权交易制度需全面完善的背景下,水污染物排污权交易环节的建设显得尤为薄弱,结合国内目前水污染物排污权交易发展现状及存在的问题,在水质模型的基础上,提出了以满足《污水综合排放标准》(GB 8978-2002)和《地表水环境质量标准》(GB 3838-2002)为前提的水污染物排污权交易计算方法,量化排污权交易可行性,预测由交易导致的水质变化。     

投加硅藻土对MBR处理校园生活污水影响的研究

实验研究了投加硅藻土对膜生物反应器处理校园生活废水效果的影响。两组膜生物反应器的对比实验结果表明:投加硅藻土有利于MBR工艺中活性污泥的培养和出水的稳定。投加硅藻土使MBR的出水COD质量浓度稳定在25 mg/L以下,BOD5质量浓度小于5 mg/L,NH3-N质量浓度0.4 mg/L左右,TP质量浓度小于0.5 mg/L,SS未检出,出水水质更加稳定。     

工业建设项目清洁生产评价若干问题探讨

从新、改、扩工业建设项目的环境影响评价角度，提出环评引入清洁生产评价的重要性，并对清洁生产评价的基本原则，评价的基本内容、评价标准等若干问题进行了探讨。     

Non-isothermal Crystallization Behaviors of Polyvinyl alcohol/Hydroxyethyl Cellulose Blend Films

In this work, polyvinyl alcohol/hydroxyethyl cellulose (PVA/HEC) blend films were fabricated by solution casting and the crystalline morphology as well as non-isothermal crystallization kinetics of the blends was investigated detailedly with polarized optical microscopy, X-ray diffraction and differential scanning calorimetry. With fixed cooling rate, the crystallization time for PVA/HEC was less than that for neat PVA. The crystallization peak temperature of PVA/HEC decreased first and then increased with the increase of HEC. With higher cooling rate, the crystallinity and crystallization time decreased. It worth noting that large spherocrystal with a size of 35 μm was observed by polarized optical microscopy for PVA/HEC blends for the first time.     

福建圆形土楼悬挑屋盖风荷载特性及气动抗风措施研究∗

福建圆形土楼悬挑屋盖属于风敏感结构,且处于我国台风多发区,为提升结构的风灾防御水平,保障其抗风安全,采用CFD 数值模拟方法对屋盖表面风荷载分布特性进行研究,同时提出了增强其抗风性能的气动抗风措施。研究表明：圆形土楼悬挑屋盖迎风面风压较大,其中,内、外悬挑屋盖端部风压系数绝对值最大,分别达到1.5 和0.75,属于风荷载敏感部位;在外悬挑屋盖端部加设竖直挡风板和波纹挡风板均可以一定程度地卸载上述风荷载敏感部位的风压值,综合比较,设置波纹挡风板较竖直挡风板对风压卸载效果更好;对于设置波纹挡风板,当其相对高度h/Hj=0.05（h 为波纹挡风板高度,Hj为地面到屋脊处距离）、倾角θ =-45°、波纹圆弧半径R = 5.5 m 时整体对屋盖表面风压卸载效果最优,其内、外悬挑屋盖端部风压系数卸载率分别达到40.1% 和54%,原因在于倾斜布置的波纹挡风板对悬挑屋盖表面来流起到阻挡作用,使得气流撞击形成的漩涡从屋盖悬挑端转移到挡风板表面,同时波纹的存在降低了内、外悬挑屋盖表面气流漩涡强度,从而达到卸载屋面风荷载的效果。     

立式锅炉爆炸机理试验研究

通过对立式锅炉爆炸事故案例汇总分析,得知立式锅炉占爆炸锅炉的60%~70%,且爆炸主要原因是缺水和超压。基于锅炉缺水导致材料力学性能改变及再进水超压造成内胆失稳,进行了材料高温力学性能试验、缺水再进水试验和内胆失稳模拟试验。得知严重缺水会造成炉胆过热超温,材料抗拉强度、弹性模量和刚度大幅下降,且350~500℃区域材料性能下降明显;立式锅炉缺水再进水爆炸事故主要是由进水汽化造成锅内压力骤升引起,缺水和超压同时存在,炉胆外压作用下失稳;立式锅炉在下脚圈与筒体连接的对接焊缝,炉胆、筒体和炉门圈的角焊缝处最易造成焊缝撕裂。