黄河三角洲海岸带生态承载力综合评价

为全面、深入认识黄河三角洲海岸带的海洋资源和生态环境特征、海洋产业结构及海洋经济发展的优势、劣势条件,选取工业废水排放量、固体废渣排放量、万元GDP能耗、岸线利用率、人均可开发海域面积、人均海岸线长度、海洋初级生产力、污染海域占海域总面积的比例、生物多样性指数、人口密度、人均海洋经济产值、GDP年均增速、科研与开发投入和环境保护支出等压力、状态、响应3类14个指标,采用压力-状态-响应模型对黄河三角洲海岸带生态承载力进行了综合量化评价.结果表明,2006-2010年黄河三角洲海岸带的承载指数和压力指数呈下降趋势,承压比则总体上呈上升趋势.根据评价结果,提出了构建高效生态产业体系、优化黄河三角洲产业空间布局、对传统产业进行生态化改造、发展新兴生态产业、保护黄河三角洲海岸带生态环境、对黄河三角洲海岸带海洋资源进行高效集约利用等提高黄河三角洲海岸带生态承载力的对策.     

Auto-adaptive Air Distribution and Structure Optimization of Ejector Burner for Biomass Alcohol Fuels

A plenty of studies on the utilization of biomass alcohol fuels have been conducted, but combustion efficiency and stability of this fuels still need to be improved. Based on biomass alcohol fuels (bio-methanol and bio-ethanol), this paper studied auto-adaptive air distribution characteristics and optimum structure parameters of an ejector burner by numerical simulation method. Also, an experiment was conducted to verify the numerical results. The results show that the mole air entrainment ratio (MAER) keeps almost constant when the ejector fuel nozzle exit locates at the segment between the ejector throat and the suction chamber entrance, but a bigger ratio α would lead to a higher MAER till the α is bigger than 8.5 for bio-methanol and 11.5 for bio-ethanol. The bio-ethanol fuel is more beneficial for air carrying role because of its big molecular weight. Operation pressure (P_w) has a little impact on MAER of the two fuels, but the rise of back pressure (P_b) would lead to rapid decrease of MAER for the two fuels. For the optimum structure burners, the MAER can be maintained at the value of theoretical complete combustion. Its changing rate is less than 2.3% for bio-methanol and 2.5% for bio-ethanol when the burner load changes from 30% to 120%, which is highly consistent with the experimental results. The optimum burner can distribute air supply automatically with the changing of burner load.     

Controlling cyanobacterial blooms by managing nutrient ratio and limitation in a large hypereutrophic lake: Lake Taihu, China

Excessive nitrogen (N) and phosphorus (P) loading of aquatic ecosystems is a leading cause of eutrophication and harmful algal blooms worldwide, and reducing nutrient levels in water has been a primary management objective. To provide a rational protection strategy and predict future trends of eutrophication in eutrophic lakes, we need to understand the relationships between nutrient ratios and nutrient limitations. We conducted a set of outdoor bioassays at the shore of Lake Taihu. It showed that N only additions induced phytoplankton growth but adding only P did not. Combined N plus P additions promoted higher phytoplankton biomass than N only additions, which suggested that both N and P were deficient for maximum phytoplankton growth in this lake (TN:TP = 18.9). When nutrients are present at less than 7.75-13.95 mg/L TN and 0.41-0.74 mg/L TP, the deficiency of either N or P or both limits the growth of phytoplankton. N limitation then takes place when the TN:TP ratio is less than 21.5-24.7 (TDN:TDP was 34.2-44.3), and P limitation occurs above this. Therefore, according to this ratio, controlling N when N limitation exists and controlling P when P deficiency is present will prevent algal blooms effectively in the short term. But for the long term, a persistent dual nutrient (N and P) management strategy is necessary.     

太原市大气PM_(2.5)中铅同位素特征研究

使用ICP-MS测定太原市2009年夏季至2010年春季典型月份中存在于PM2.5上的铅(Pb)及同位素特征,分析了铅的浓度水平、季节变化特征,探讨了铅同位素丰度比特征,并由富集因子法初步解析了铅的来源。结果显示,太原市环境大气中存在于PM2.5上的Pb含量为270.83ng/m3,低于我国环境空气质量标准(GB3095-2012)中对颗粒物中铅的年均限值,在国内属中等水平。冬季存在于PM2.5中的Pb浓度水平最高,与取暖燃煤排放有关;扬尘中的Pb富集则对春季的Pb污染有较大贡献。Pb与PM2.5的相关性显示夏季和冬季二者来源一致,皆为燃煤排放;206 Pb/207 Pb与208 Pb/206 Pb的同位素丰度比特征也表明PM2.5中Pb的主要源于燃煤排放,由于冬季煤炭消费量较高,其燃烧排放对PM2.5中Pb的贡献高于其他季节。采样期间PM2.5中Pb的富集因子(20.45)显示,Pb主要源于人为活动的排放;春季的富集因子(10.76)接近10,表明春季时自然源的Pb对PM2.5的贡献较大。     

加载减速排放测试数据统计分析方法的改进研究

加载减速法（LugDown）测量被测车辆处于100％、90％和80％VelMaxHP三个速度工况下的排气光吸收系数（k）和100％VelMaxHP速度工况下的最大轮边功率值（MaxHP）,数据内涵增强,统计分析较为复杂。为解决此问题,本文根据LugDown法排气控制指标与测量数据特点,提出了排放最大值均值和功率比值统计分析方法,并将其用于广州市柴油车LugDown法排气检测数据的分析,结果令人满意。     

崇明岛中长期碳排放预测及其影响因素分析

为更好地推动崇明低碳生态岛的建设,在应用以自下而上的部门法为基础的区域范围温室气体排放评估核算方法,全面核算崇明岛能源消费及温室气体排放现状的基础上,应用LEAP模型,通过情景分析预测崇明岛中长期能源消费需求以及温室气体排放水平,并进一步应用对数平均指数法(LMDI)对影响崇明岛未来温室气体排放的主要因素进行了定量分析。研究表明:参考情景下,崇明岛能源消费总量从2010年的101万吨标煤增加到2050年的533万吨标煤,净碳足迹从2010年的238万吨CO2e增加到2050年的579万吨CO2e。崇明岛能源消费需求和碳排放增加的主要驱动因素是未来的经济发展、人口增长和生活水平的提高,但是通过一系列的优化,尤其是能源结构的变化和能耗强度的下降,减排情景下,崇明岛能源消费总量有可能在2039年左右达到峰值,并有望在2050年左右实现"零碳岛"的长期发展目标。结合定量分析的结论,进一步提出了实现崇明岛低碳发展中长期目标的可能性和重点发展领域。     

Classification of dispersibility for combustible dust based on Hausner ratio

Mixing of combustible dust and oxidant is one of five essential prerequisites in the dust explosion pentagon, requiring that particles originally in mutual contact within the deposits be separated and suspended in the air. However, dust dispersion never proceeds with 100% efficiency, with inevitable particle agglomeration, and an inherent trend toward settling out of suspension. Dispersibility is defined to describe the ease of dispersion of a dust and the tendency of the particulate matter to remain airborne once a dust cloud has been formed. Pioneers made contributions to classify dust dispersibility by introducing dustiness group (DG), dustability index (DI), NIOSH dispersion chamber and in-situ particle size analysis. Issues remained including the difficulty in comparing results from different methods, as well as the availability of some high-tech testing apparatus.This study aims to provide a quick and universal testing method to estimate the dispersion property of combustible dust. A new dispersibility classification was developed based on dimensionless numbers Hausner ratio and Archimedes number. Four dispersibility classes (DCs) were proposed from one to four, with a larger number meaning better dispersibility. Results for more than a dozen dust samples and mixtures thereof showed the new method is useful in dust explosion research. The consistency in classifying dust dispersion properties between the DC method and previous methods was good. Changes in DC well explained our earlier findings on suppressant enhanced explosion parameter (SEEP) phenomenon attributed to the improvement in dust dispersibility. Hausner ratio and Archimedes number, as easily measured parameters, can be quite advantageous to assess dust dispersibility, permitting a proper risk assessment for the formation of explosible dust clouds.     

Enhancing anoxic denitrification of low C/N ratio wastewater with novel ZVI composite carriers

External organic carbon sources are needed to provide electron donors for the denitrification of wastewater with a low COD/NO₃^--N（C/N） ratio, increasing the treatment cost. The economic strategy is to enhance the bioactivity and/or biodiversity of denitrifiers to efficiently utilize organic substances in wastewater. In this study, novel zero-valent iron（ZVI） composite carriers were prepared and implemented in a suspended carrier biofilm reactor to enhance the bioactivity an...     

Wall losses of oxygenated volatile organic compounds from oxidation of toluene: Effects of chamber volume and relative humidity

Vapor wall losses can affect the yields of secondary organic aerosol. The effects of surface-to-volume (S/V) ratio and relative humidity (RH) on the vapor-wall interactions were investigated in this study. The oxygenated volatile organic compounds (OVOCs) were generated from toluene-H₂O₂ irradiations. The average gas to wall loss rate constant (k_gw) of OVOCs in a 400 L reactor (S/V = 7.5 m⁻¹) is 2.47 (2.41 under humid conditions) times higher than that in a 5000 L reactor (S/V = 3.6 m⁻¹) under dry conditions. In contrast, the average desorption rate constant (k_wg) of OVOCs in 400 L reactor is only 1.37 (1.20 under humid conditions) times higher than that in 5000 L reactor under dry conditions. It shows that increasing the S/V ratio can promote the wall losses of OVOCs. By contrast, the RH effect on k_gw is not prominent. The average k_gw value under humid conditions is almost the same as under dry conditions in the 400 L (5000 L) reactor. However, increasing RH can decrease the desorption rates. The average k_wg value under dry conditions is 1.45 (1.27) times higher than that under humid conditions in the 400 L (5000 L) reactor. The high RH can increase the partitioning equilibrium timescales and enhance the wall losses of OVOCs.