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161.
特长公路隧道集中排烟方式研究 总被引:4,自引:1,他引:3
纵向通风排烟是我国长大公路隧道发生火灾时通风的主要形式,目前开始应用一种新型的特长公路隧道纵向通风集中排烟方式。本文借助CFD三维数值模拟技术,对两种排烟方式在火灾时的烟气控制效果进行了对比分析,研究了顶部设排烟道时,不同排烟开口大小和排烟口间距对隧道火灾时排烟效果的影响。研究表明:顶部设排烟道排烟较纵向通风排烟有较好的烟气控制效果,排烟口的设置间距和开口大小将影响隧道火灾时的排烟特性。 相似文献
162.
Salpie Djoundourian 《Environment, Development and Sustainability》2009,11(2):427-438
The paper reviews and assesses the evolution of the environmental movement in both the public and the private sector in Lebanon.
It studies the public sector involvement in the environmental movement by reviewing the commitments made by the government
to the local, regional and international communities. The paper presents a summary of all the decisions, decrees, and laws
pertaining to environmental protection that the Lebanese government has instituted over time, as well as all the conventions
and agreements that the country has ratified and/or signed. Compared to the Arab world in the Middle East and North Africa,
Lebanon is relatively more active and integrated in the world community. Using the total number of established environmental
organizations and the level of reported activities aimed at spreading environmental awareness and educating people as indicators
of private sector involvement in the environmental movement, the paper concludes that the post war era is characterized by
a significant increase in the number of established organizations. It also concludes that there is a co-movement between economic
and environmental variables.
Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue. 相似文献
163.
Christopher J. Hilson 《环境政策》2016,25(2):248-267
Strategic lawsuits against public participation (SLAPPs) brought against the environmental movement in the UK since the 1990s are examined. SLAPPs, a form of Green backlash, have been mobilised across a wide range of policy areas that have seen vigorous campaigning and protest by the movement, including roads, GMOs and, more recently, climate change. SLAPPs are typically regarded as a threat, designed to close down democratic free speech and protest. However, in the UK, there are some notable cases where the environmental movement has been able to use agency to convert what may appear as a legal threat into a positive legal or media opportunity. 相似文献
164.
Huili Zhang Raf Dewil Jan Degrève 《International Journal of Sustainable Engineering》2014,7(4):307-312
Cement manufacturing consumes two main types of energy: fuel and electricity. On average, energy costs represent 40% of the total production costs per ton of cement. The challenge is to reduce the consumption of energy to about 3000 MJ/ton clinker without the consumption of massive additional amounts of electricity, which is normally associated with additional fuel-saving measures. This can only be achieved by implementing sound thermal energy optimization measures. Energy-efficient suspension cement kilns are now widely applied and use a cascade of cyclonic pre-heaters of moist particulate feedstock, with heat transfer from hot kiln exhaust gas to particles being a function of heat transfer coefficient, temperature difference and gas–solid contact mode and time. The gas–solid contact mode and time depend on particle movement in cyclones, which has previously been studied by positron emission particle tracking. Heat transfer is governed by Nusselt–Reynolds equations, with gas velocity and properties being a function of the temperature profile along the cascade of cyclones. A stepwise approach of the design thus combines changing hydrodynamics and heat transfer along the successive cyclones, with the overall thermal balance of the cascade as control. This approach leads to major design recommendations, as developed in the present paper. 相似文献
165.
S. A. Clay R.H. Dowdy J.A. Lamb J.L. Anderson B. Lowery R.E. Knighton 《Journal of environmental science and health. Part. B》2013,48(3):259-278
Abstract This study was conducted to evaluate atrazine (2‐chloro‐4‐ethylamino‐6‐isopropyl‐1, 3, 5‐triazine) and alachlor (2‐chIoro‐N‐(methoxymethyl)acetamide) dissipation and movement to shallow aquifers across the Northern Sand Plains region of the United States. Sites were located at Minnesota on a Zimmerman fine sand, North Dakota on Hecla sandy loam, South Dakota on a Brandt silty clay loam, and Wisconsin on a Sparta sand. Herbicide concentrations were determined in soil samples taken to 90 cm four times during the growing season and water samples taken from the top one m of aquifer at least once every three months. Herbicides were detected to a depth of 30 cm in Sparta sand and 90 cm in all other soils. Some aquifer samples from each site contained atrazine with the highest concentration in the aquifer beneath the Sparta sand (1.28 μg L‐1). Alachlor was detected only once in the aquifer at the SD site. The time to 50% atrazine dissipation (DT50) in the top 15 cm of soil averaged about 21 d in Sparta and Zimmerman sands and more than 45 d for Brandt and Hecla soils. Atrazine DT50 was correlated positively with % clay and organic carbon (OC), and negatively with % fine sand. Alachlor DT50 ranged from 12 to 32 d for Zimmerman and Brandt soils, respectively, and was correlated negatively with % clay and OC and positively with % sand. 相似文献
166.
长江八里江江段江豚种群数量、行为及其活动规律与保护 总被引:13,自引:0,他引:13
1989-1999年,在长江八里江江段对江豚进行了28次往返观察和8次定点观察。结果表明,近10年八里江江段江豚种群数量遥感量逐年呈明显递减趋势,平均每年以7.3%速率递减;1996年后,枯水季节江豚不再进行江一湖迁移,其活动范围仅限于约20km长的八里江江口上下江段,较1993年以前缩短了约40km。江豚在八里江江段的行为多种多样,通过对江豚种群在八里江江段的集群、摄食、逃避、发情与交配、抚幼、歇息和玩耍行为的描述、比较和分析,认为长江八里江江段是江豚典型的摄食和抚幼场所,同时也是江豚大规模集群的适宜栖居地。提出了加强八里江江段江豚种群常年监测的必要性,并对八里江江段江豚种群的就地保护提出了建议。 相似文献
167.
渤海滩涂沉积物中石油污染物的迁移-转化规律研究 总被引:2,自引:0,他引:2
采用紫外分光光度法对2003年夏季渤海滩涂表层沉积物和海水中石油烃含量进行了分析,探讨了海水中可溶油在滩涂沉积物中的迁移转化特征及其影响因素。结果表明,沉积物中石油烃含量在(55.8~2563.4)×10-6,平均值为555.82×10-6,与海洋沉积物质量(GB18668-2002)500×10-6相比,超标率为50%,超标倍数为1.05~5.13倍;受潮流作用和沉积环境的影响,石油烃含量自岸向海呈由低到高的分布特征;研究区是典型的淤泥质海岸带,由于其沉积物颗粒细,有机质含量高,很容易吸附石油烃;沉积物中石油烃是难生物降解的多环芳烃类。 相似文献
168.
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