Chemical characterization of size-resolved aerosols in four seasons and hazy days in the megacity Beijing of China

Size-resolved aerosol samples were collected by MOUDI in four seasons in 2007 in Beijing. The PM10 and PM1.8mass concentrations were 166.0 ± 120.5 and 91.6 ± 69.7 μg/m~3, respectively,throughout the measurement, with seasonal variation: nearly two times higher in autumn than in summer and spring. Serious fine particle pollution occurred in winter with the PM1.8/PM10 ratio of 0.63, which was higher than other seasons. The size distribution of PM showed obvious seasonal and diurnal variation, with a smaller fine mode peak in spring and in the daytime. OM(organic matter = 1.6 × OC(organic carbon)) and SIA(secondary inorganic aerosol) were major components of fine particles, while OM, SIA and Ca_2+were major components in coarse particles. Moreover, secondary components, mainly SOA(secondary organic aerosol) and SIA,accounted for 46%–96% of each size bin in fine particles, which meant that secondary pollution existed all year. Sulfates and nitrates, primarily in the form of(NH_4)_2SO_4, NH_4NO_3, Ca SO_4, Na_2SO_4 and K_2SO_4, calculated by the model ISORROPIA II, were major components of the solid phase in fine particles. The PM concentration and size distribution were similar in the four seasons on non-haze days, while large differences occurred on haze days, which indicated seasonal variation of PM concentration and size distribution were dominated by haze days. The SIA concentrations and fractions of nearly all size bins were higher on haze days than on non-haze days, which was attributed to heterogeneous aqueous reactions on haze days in the four seasons.     

Why are Californians interested in hybrid cars?

This paper explores quantitatively Californians' interest in hybrid electric vehicles (HEV) based on a statewide phone survey conducted in July 2004 by the Public Policy Institute of California. The paper develops ordered choice models and factors that summarise beliefs about energy and the environment using principal component analysis. As expected, Californians concerned about the environment, energy efficiency, global warming and recent increases in the price of gasoline state a higher interest in hybrids; an even more important reason for considering hybrid electric vehicles, however, is the possibility of using high occupancy vehicle (HOV) lanes while driving alone, especially for people with potentially long commutes to work. The findings also suggest that beliefs about energy and the environment should be included in vehicle type choice models.     

Spent rechargeable lithium batteries in e-waste: composition and its implications

The amount of spent rechargeable lithium batteries （RLBs） is growing rapidly owing to wide application of these batteries in portable electronic devices and electric vehicles, which obliges that spent RLBs should be handled properly. Identification of spent RLBs can supply fundamental information for spent RLBs recycling. This study aimed to determine the differences of physical components and chemical compositions among various spent RLBs. All the samplings of RLBs were rigorously dismantled and measured by an inductive coupled plasma atomic emission spectrometer. The results indicate that the average of total weight of the separator, the anode and the cathode accounted for over 60% of all the RLBs. The weight ratio of valuable metals ranged from 26% to 76%, and approximately 20% of total weight was Cu and Al. Moreover, no significant differences were found among different manufacturers, applications, and electrolyte types. And regarding portable electronic devices, there is also no significant difference in the Co-Li concentration ratios in the leaching liquid of RLBs.     

金属压力容器水压试验声发射检测

通过对容积为504．94m3的某型号压力容器出厂前水压试验的声发射检测,分析了其在升压和保压过程中的声发射信号特征及其来源。结合AE信号参数、波形及定位图分析,对该容器进行了声发射活性评价,确定需要后续复检的强活性区域。文章为压力容器的声发射检测和安全评价提供了理论指导和参考数据。     

城市轨道交通系统组元脆弱性评价研究

为有效降低城市轨道交通系统的脆弱性,在脆弱性理论的基础上,界定城市轨道交通系统组元脆弱性的概念与内涵,并将其影响因素划分为人员、设备与环境3个指标组。整合DEMATEL、ANP与模糊VIKOR这3种系统分析评价方法,构建集成DEMATEL-ANP-FVIKOR方法的城市轨道交通系统组元脆弱性评价模型,并通过对北京地铁典型车站的评价来验证该评价模型的有效性。研究结果表明,该评价模型切实可行,能够对城市轨道交通系统组元脆弱性进行有效量化评价分析。     

Dynamic response and effect of apertures on explosion parameters of flameproof apparatus

Explosion parameters for closed flameproof apparatus are changed when apertures like gap (e.g. push button) and porous structures (breathing element) are introduced on the cover or wall of the flameproof enclosures. Similarly, an interconnecting tube between two enclosures, results in significant change in explosion parameters. It is observed that the maximum explosion pressure, maximum rate of pressure rise and severity index are higher for enclosures with apertures on cover or body than that of enclosures without apertures. In case of two interconnected identical enclosures, the explosion parameters are increased in the secondary enclosure and higher than that of primary enclosure and also of isolated enclosure.     

Propagation of ethylene–air flames in closed cylindrical vessels with asymmetrical ignition

A study of explosions in several elongated cylindrical vessels with length to diameter L/D = 2.4–20.7 and ignition at vessel's bottom is reported. Ethylene–air mixtures with variable concentration between 3.0 and 10.0 vol% and pressures between 0.30 and 1.80 bara were experimentally investigated at ambient initial temperature. For the whole range of ethylene concentration, several characteristic stages of flame propagation were observed. The height and rate of pressure rise in these stages were found to depend on ethylene concentration, on volume and asymmetry ratio L/D of each vessel. High rates of pressure rise were found in the early stage; in later stages lower rates of pressure rise were observed due to the increase of heat losses. The peak explosion pressures and the maximum rates of pressure rise differ strongly from those measured in centrally ignited explosions, in all examined vessels. In elongated vessels, smooth p(t) records have been obtained for the explosions of lean C₂H₄–air mixtures. In stoichiometric and rich mixtures, pressure oscillations appear even at initial pressures below ambient, resulting in significant overpressures as compared to compact vessels. In the stoichiometric mixture, the frequency of the oscillations was close to the fundamental characteristic frequency of the tube.     

顶空气相色谱质谱法分析污泥恶臭成分

采用顶空气相色谱质谱(HS/GC-MS)联用技术对污泥恶臭成分进行检测,从污泥恶臭成分中分离多种化合物,并鉴定出烷、醛及苯等有机物。不同地区污泥的性质不尽相同,从而使恶臭成分也产生很大差异。HS/GC-MS法是一种分析污泥恶臭成分的有效方法,为污泥恶臭污染的防治提供了科学依据。     

南京大气细颗粒物中水溶性组分的污染特征

为了解南京城区大气细颗粒物中水溶性组分的污染特征,在国控点草场门进行了连续一年的PM_2.5采样与分析。6种离子日均浓度为5.29~67.6 μg/m³,其中SO₄^2-、NH₄⁺、NO₃^-是PM_2.5的主要组成成分,6 种离子约占PM_2.5总质量的31%,SO₄^2-、NO₃^-和NH₄⁺相关性较好,NH₄⁺是PM_2.5中硫酸盐和硝酸盐中居于主导地位的离子。     

太湖流域上游河流污染空间分布特征研究

为把握太湖流域上游西北部河网区域水体的N、P污染特征及其空间分布,2010年8月在该区域内的武进港 直湖港水系、洮滆水系、丹扁孟河（丹金溧漕运河、扁担河及孟津河）以及宜溧河水系的河网,监测了39个河流断面的水质。研究表明,4水系TN平均浓度分别为388、283、291及193 mg/L,DTN占TN比重分别为9180%、7843%、7001%及8444%,河网氮输出均以DTN为主。在DTN中NO-3 N浓度所占比重分别为6747%、5275%、7748%及4281%,NH+4 N浓度所占比重分别为1633%、3316%、1127%及4351%。TP平均浓度分别为059、030、026及015 mg/L,DTP所占比重分别为6213%、4019%、4673%及3197%,而PO3-4 P浓度占DTP比重分别为2073%、5461%、4327%及7772%。武进港 直湖港水系N平均浓度显著（〖WTBX〗p〖WTBZ〗<001）高于宜溧河水系,与其它两水系无显著差异,P平均浓度显著（〖WTBX〗p〖WTBZ〗<005）高于宜溧河水系和丹扁孟河,与洮滆水系无显著差异。影响太湖流域上游西北部区域河流水网水质的主导因素为氮污染,而其中以DTN污染最为严重。太湖西北部是蓝藻水华暴发的重灾区,上游区域DTN的大量输入,将成为引发太湖水体生态系统灾变的潜在风险