Multi-dimension apportionment of clean air “parade blue”phenomenon in Beijing

The mass concentration and major chemical components of fine particulate matter were measured before, during and after Beijing''s massive parade commemorating 70th anniversary of the Chinese Victory in World War II on September 3, 2015. Regional emission inventory, positive matrix factorization (PMF), observations from space and backward air mass trajectories were jointly applied to identify the major pollution sources and their temporal and spatial variations. The contributions of emissions, their variations and the meteorological conditions related to the “parade blue” phenomenon in Beijing and its surrounding areas were investigated in detail. The main cause of the decreased PM_2.5 mass concentration was attributed to the absolute reduction in emissions of primary air pollutants. The chemical composition of PM_2.5 varied significantly before, during and after the parade. Fugitive dust particles were well controlled, the secondary formation of PM_2.5 was reduced along with the controlled gaseous precursors'' emissions from vehicles and industrial sources during the temporary intensified control period. During the parade period, the SO₂ and NO₂ column concentrations in Beijing and the surrounding areas decreased sharply, indicating that the coordinated reduction in primary emissions from the surrounding areas of Beijing played an important role in lowering the ambient concentration of SO₂ and NO₂ and accordingly lowered PM_2.5 and improved the regional air quality. A comparison of the temperature, humidity, and wind speed and direction during the same periods in 2014 and 2015 showed that the meteorological conditions positively influenced the achievement of “parade blue”.     

17α-Ethynylestradiol biodegradation in different river-based groundwater recharge modes with reclaimed water and degradation-associated community structure of bacteria and archaea

This study investigated 17α-ethynylestradiol(EE2) biodegradation process and primary metabolic pathways associated with community structures of microorganism during groundwater recharge using reclaimed water. The attenuation rate is 1.58 times higher in wetting and drying alternative recharge(WDAR) than in continual recharge(CR). The primary biotransformation pathways of EE2 in WDAR system began with the oxidation of C-17 on ring D to form a ketone group, and D-ring was subsequently hydroxylated and cleaved. In the CR system, the metabolic pathway changed from the oxidation of C-17 on ring D to hydroxylation of C-4 on ring A, and ring A or B subsequently cleaved; this transition was related to DO, and the microbial community structure. Four hundred fifty four pyrosequencing of 16 s r RNA genes indicated that the bacterial communities in the upper layer of the WDAR system were more diverse than those found in the bottom layer of the CR system; this result was reversed for archaea. Unweighted Uni Frac and taxonomic analyses were conducted to relate the change in bacterial community structure to the metabolic pathway. Microorganism community diversity and structure were related to the concentrations of dissolved oxygen, EE2 and its intermediates in the system. Five known bacterial classes and one known archaeal class, five major bacterial genera and one major archaeal genus might be involved in EE2 degradation. The findings of this study provide an understanding of EE2 biodegradation in groundwater recharge areas under different recharging modes and can facilitate the prediction of the fate of EE2 in underground aquifers.     

短程硝化-反硝化生物脱氮技术研究

将短程硝化-反硝化生物脱氮技术与传统生物脱氮技术进行了比较,论述了短程硝化-反硝化生物脱氮技术的机理及特点。分析了实现亚硝酸盐积累的影响因素,包括温度、溶解氧浓度、pH值、分子态游离NH3浓度和泥龄。结合典型工艺,提出了目前短程硝化-反硝化脱氮技术存在的问题及改进建议。     

关于危险废物处置项目投资营运模式的探讨

探讨了我国危险废物处置项目投资及营运模式，提出政府、企业共同出资建设，采用现代企业制度和市场化营运模式符合我国现阶段的国情。     

灾害保险赔案数据库的建立及应用--以湖南省溆浦县保险赔案数据库为例

保险公司的赔案资料记录了保险理赔的货币过程,它是进行保险赔付审计分析和保险出险原因分析最可靠的实证材料,作者利用１９８１￣１９９３年湖南省保险公司企业财产险,家庭财产险,货物运输险,种养业险等四个主要保险险种的赔案资料,以行政县,区为基本单元建立了达２３３７６１条记录的灾害保险赔案数据库。以湖南省溆浦县保险公司的赔案数据库为例,对其近１０多年来的保险灾害情况进行了初步分析,为当地保险公司提出了保险     

Use of life cycle assessment methodology for determining phytoremediation potentials of maize-based cropping systems in fields with nitrogen fertilizer over-dose

Using the life cycle assessment (LCA) method, we analyzed the effects of different cropping systems (sole maize (CK), maize + soybean (CST) and maize + groundnut (CGT)) on the environment. The comprehensive index of environmental impacts varied in the order, sole maize > maize + groundnut > maize + soybean, with corresponding intercropping values of 0.1295, 0.1229 and 0.0945, respectively. The results showed that intercropping maize with suitable plants (e.g., groundnut and soybean) could reduce the adverse effects of over-application of nitrogen fertilizer on the environment. The study further showed that the LCA method may be a convenient and effective approach for analyzing the environmental impact of fertilizer management in agricultural fields.     

A 14-year measurement of toxic elements in atmospheric particulates in Hong Kong from 1995 to 2008

Toxic elements in the atmosphere can enter and accumulate in the human body, seriously impacting human health. In this study, we analyzed a 14-year （1995-2008） measurement of three toxic elements （As, Cd and Cr） in PMlo in Hong Kong, China. The pollution of these toxic elements in Hong Kong was not serious. The trend analysis showed that As and Cr in PM10 increased at a statistically significant level （p〈0.05） during the 14-year period, while the Cd in PM10 did not change significantly. Typical seasonal variations were observed for all three toxic elements, largely in relation to the Asian monsoon. Hourly 10-day backward trajectories were computed and cate- gorised into four groups. The continental air masses showed much higher concentrations of the three toxic elements than the marine air masses. The abundances of As and Cd in the PM10 were much higher in the continental air masses than those in the marine air masses, while the abundances of Cr showed an opposite pattern. The trends of the three toxic elements in East China＇s air mass were consistent with those in the overall data set ofHong Kong. Examination of the toxic element data recorded at urban sites and a roadside site also indicated a large contribution of external air masses to particulate As and Cd in Hong Kong. These results suggest that the long-range transport from the mainland of China is the dominant contributor to particulate As and Cd, while both local and long-distance sources determine the particulate Cr in Hong Kong.     

脉冲袋式除尘器在水泥厂的应用

具体阐述了各式不同种类的脉冲袋式除尘器在水泥厂内针对破碎机、球磨机、干法预分解窑和干法中空窑及原料储存、运输等方面的应用。     

Numerical computation and characteristic analysis on the center shift of fire whirls in a ship engine room fire

The existence of fire whirls in some ship engine room is studied by using the basic elements of the fire whirls formation. The temperature characteristic of fire whirls are used to study the path shift of fire whirls and the result is nearly circular. The center shift angular velocity of fire whirls is analyzed with the least square fitting in the conditions of the constant wind velocity and the variable wind velocity from four sides. In the situation of the constant wind velocity, the result shows that the center shift angular velocity of fire whirls comply with the change regularity of a cube polynomial with different wind speed. When the wind velocity is more than 6.58 m/s, it strongly affects the change rate of the center shift angular velocity. However, in the situation of variable wind velocity, when the change rule of wind velocity follow increasing or descending regularity, the change law of the center shift angular velocity is proportional to the size of the wind velocity, but when the wind velocity is random variation, the change fluctuation of center shift angular velocity is comparatively small. Computational results have important significance for the structure fireproofing, fire evaluation and shipping design.     

Mechanism research on coal and gas outburst during vibration blasting

The coal and gas outburst results from plenty of factors, while vibration is the most important factor among them. Therefore, the influences of vibration acting on gas desorption and coal structure had been conducted. And the mechanism of coal and gas outburst induced by vibration was illustrated through examples. The results showed that the gas desorption accelerates under the action of vibration, and then the gas gradient increases. Meanwhile, vibration would increase and expand fractures in the internal coal body, which aggravates the risk of coal and gas outburst greatly. In conclusion, vibration is a more important factor attributable to coal and gas outburst compared with other coal mining method, mining technology and construction method.