丙烯腈、醋酸乙烯酯罐区火险分析及对策

对丙烯腈、醋酸乙酯罐系统危险性及罐区泄漏潜在危险性进行了系统分析。并对丙烯腈、醋酸乙烯酯罐区的防火防爆提出了相应的对策,对泡沫消防设备及可燃气体检测器灭火系统的可行性和实用性进行了重点介绍和探讨。     

Beryllium-7 in near-surface air and deposition at Brisbane, Australia

Measurements of 7Be concentrations in near-surface air and 7Be deposition were carried out at Brisbane, Australia. Concentrations of 7Be in near-surface air measured over 4 years show seasonal variations with values above the annual mean occurring mainly in the spring and summer months of each year. These higher concentrations coincide with the expected influx of stratospheric air to the planetary boundary layer in early spring and higher rates of convective circulation within the troposphere during summer. 7Be deposition measurements over 3 years show seasonal variations similar to the seasonal rainfall pattern. There is a statistically significant (p<0.001) linear relationship between monthly (7)Be deposition and rainfall amount. This relationship is used to calculate the net cumulative (7)Be areal activity density.     

Describing the annual cyclic behaviour of 7Be concentrations in surface air in Oceania

Surface air concentrations of (7)Be at a number of stations in Oceania show a distinct annual cycle. We apply a sinusoidal model to describe this cycle. The results show that peak (7)Be concentrations in surface air occur during early spring at tropical latitudes and during mid-to-late summer at middle latitudes. Comparison with available (90)Sr surface air data for the southern hemisphere indicates that stratosphere-to-troposphere exchange is an active atmospheric process controlling the (7)Be annual cycle throughout the Oceania region. Vertical transport of air within the troposphere also seems to influence the observed annual cycle. Seasonality in rainfall is not thought to control the annual cyclic behaviour of (7)Be in surface air.     

超音速虹吸式空气雾化喷嘴雾化影响因素实验研究*

为掌握超音速虹吸式空气雾化喷嘴雾化机理及特性,采用流体力学线性不稳定理论分析雾化机理,通过喷雾实验研究不同因素对雾化性能的影响及对比不同类型喷嘴的雾化效果。研究结果表明:随着距喷嘴出口距离增加,超音速虹吸式空气雾化喷嘴在雾滴破碎后碰撞聚合作用由强到弱,300 mm内雾滴粒径增长速率明显,300 mm外雾滴粒径增长速率较缓。随着供气压力增加,超音速虹吸式空气雾化喷嘴雾滴粒径逐渐减小,在实测距离内SMD（平均粒径）最小为17.5 μm。不同供气压力下,超音速虹吸式空气雾化喷嘴随距离增加,雾滴粒径增长趋势基本一致。有效射程内供气压力为0.1~0.5 MPa时,SMD仅为17.5~31.16 μm。对比实验中,超音速虹吸式空气雾化喷嘴SMD比内混式空气雾化喷嘴和X旋流型压力喷嘴小53.5%~74.0%。     

循环温度荷载下管式能量桩荷载传递机理研究

基于模型试验方法,开展加热(制冷)工作模式下,实心和管式能量桩的热响应测试研究;分析多次加热/制冷循环作用下两种能量桩的热力耦合特性,实测桩顶位移、桩身应变、以及桩侧摩阻力等变化规律,并对实际运行过程中实心和管式能量桩的承载特性进行初步讨论。研究结果表明,相同直径的管式能量桩换热效率高于实心能量桩,管式能量桩对加热循环的热响应要高于实心能量桩;多次循环后,能量桩桩顶产生塑性沉降、桩身产生微小的塑性应变,桩侧摩阻力值增加。     

等离子体改性对活性炭纤维表面化学结构的影响

采用放电等离子体对活性炭纤维表面进行改性,通过改变活性炭纤维的化学官能团来强化活性炭纤维对SO2和NOx的吸附和催化作用。利用XPS、FTIR等方法对改性活性炭纤维的化学性质进行表征,研究了活性炭纤维表面官能团在等离子体改性过程中的转化规律和机理。实验结果表明:放电改性过程可以有效地向活性炭纤维表面引入有利于脱硫脱氮的含氧、含氮官能团;当电压为8kV,放电时间为5min时,放电改性活性炭纤维的效果最佳。     

Impact of climate change on vulnerability of forests and ecosystem service supply in Western Rhodopes Mountains

The vulnerability of forest ecosystem services to climate change is expected to depend on landscape characteristic and management history, but may also be influenced by the proximity to the southern range limit of constituent tree species. In the Western Rhodopes in South Bulgaria, Norway spruce is an important commercial species, but is approaching its current southern limit. Using climate sensitive forest models, we projected the impact of climate change on timber production, carbon storage, biodiversity and soil retention in two representative landscapes in the Western Rhodopes; a lower elevation landscape (1000–1450 m a.s.l) dominated by mixed species forests, and a higher elevation landscape (1550–2100 m a.s.l.) currently dominated by spruce. In both landscapes climate change is projected to induce a shift in forest composition, with drought-sensitive species, such as Norway spruce, being replaced by more drought-tolerant species such as Scots pine and black pine at lower elevations. In the higher elevation landscape a reduction in spruce growth is projected, particularly under the more severe climate change scenarios. Under most climate scenarios a reduction in growing stock is projected to occur, but under some scenarios a moderate increase in higher elevation stands (>1500 m a.s.l.) is expected. Climate change is projected to negatively influence carbon storage potential across landscapes with the magnitude depending on the severity of the climate change scenario. The impact of climate change on forest diversity and habitat availability is projected to differ considerably between the two landscapes, with diversity and habitat quality generally increasing at higher elevations, and being reduced at lower elevations. Our results suggest that if currently management practices are maintained the sensitivity of forests and forest ecosystem services in the Western Rhodopes to climate change will differ between low and higher elevation sites and will depend strongly on current forest composition.     

硅藻土固定化颗粒污泥对海水养殖废水除氨性能

针对实际海水养殖废水低碳高氮的特点,采用间歇式活性污泥法(SBR)和好氧活性污泥添加硅藻土载体的方式,考察硅藻土载体和活性污泥共同作用下的好氧曝气系统对海水养殖废水中氨态氮(NH+4-N)、亚硝酸态氮(NO-2-N)和化学耗氧量(COD)的去除效果,以及对污泥沉降性能和硝化细菌特征的影响。实验结果表明,常温条件下,溶解氧(DO)≥4.5mg/L,p H控制在7.0~8.0,HRT为11 h,沉降时间10 min,反应器可以处理NH+4-N浓度在50 mg/L左右的海水养殖废水,NH+4-N和COD去除率分别达到98.93%左右和76.62%以上,NO-2-N出水浓度低于0.028 mg/L。载体污泥颗粒照片和扫描电镜结果表明,添加硅藻土载体内核后,颗粒污泥的成熟期缩短,颗粒的稳固度和沉降性能提高。在系统启动成功稳定运行后,通过FISH分析表明,在氨氧化菌(AOB)与亚硝酸盐氧化菌(NOB)成为优势菌群后,AOB大约占总菌群的33.5%,并且AOB与NOB菌群数量约为1∶1.33,AOB和NOB两大类菌群之和约占总菌群的77.2%,成为系统中优势菌群。     

Municipal solid waste source-separated collection in China: A comparative analysis

A pilot program focusing on municipal solid waste (MSW) source-separated collection was launched in eight major cities throughout China in 2000. Detailed investigations were carried out and a comprehensive system was constructed to evaluate the effects of the eight-year implementation in those cities. This paper provides an overview of different methods of collection, transportation, and treatment of MSW in the eight cities; as well as making a comparative analysis of MSW source-separated collection in China. Information about the quantity and composition of MSW shows that the characteristics of MSW are similar, which are low calorific value, high moisture content and high proportion of organisms. Differences which exist among the eight cities in municipal solid waste management (MSWM) are presented in this paper. Only Beijing and Shanghai demonstrated a relatively effective result in the implementation of MSW source-separated collection. While the six remaining cities result in poor performance. Considering the current status of MSWM, source-separated collection should be a key priority. Thus, a wider range of cities should participate in this program instead of merely the eight pilot cities. It is evident that an integrated MSWM system is urgently needed. Kitchen waste and recyclables are encouraged to be separated at the source. Stakeholders involved play an important role in MSWM, thus their responsibilities should be clearly identified. Improvement in legislation, coordination mechanisms and public education are problematic issues that need to be addressed.     

Quantifying air pollution attenuation within urban parks: an experimental approach in Shanghai, China

Parks with various types of vegetations played an important role in ameliorating air quality in urban areas. However, the attenuation effect of urban vegetation on levels of air pollution was rarely been experimentally estimated. This study, using seasonal monitoring data of total suspended particles (TSP), sulfur dioxide (SO(2)) and nitrogen dioxide (NO(2)) from six parks in Pudong District, Shanghai, China, demonstrated vegetations in parks can remove large amount of airborne pollutants. In addition, crown volume coverage (CVC) was introduced to characterize vegetation conditions in parks and a mixed-effects model indicated that CVC and the pollution diffusion distance were key predictors influencing pollutants removal rate. Therefore, it could be estimated by regression analysis that in summer, urban vegetations in Pudong District could contribute to 9.1% of TSP removal, 5.3% of SO(2) and 2.6% of NO(2). The results could be considered for a better park planning and improving air quality.