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911.
为探明水幕排烟系统对隧道内烟气控制和排烟效率的影响,通过火灾动力学求解器(FDS)研究不同排烟风量下隧道内烟气、温度和速度分布。结果表明:排烟量小于100 m3/s时,水幕无法有效地阻隔有毒烟气的蔓延;当火源热释放速率(HRR)为10、20及30 MW时,排烟量分别为100、160和180 m3/s,能将烟气限制在水幕排烟系统内;在水幕的作用下,水幕外的温度分布均满足人员逃生的需要(小于80℃),在水幕排烟系统中烟气控制要比温度控制更为重要;相同火源HRR下,排烟口的排烟效率随着排烟量先增大后减小;排烟口的吸穿效应在水幕排烟系统中很难出现,排烟口吸入位于隧道底部混有大量新鲜空气的烟气是造成排烟效率降低的主要原因。 相似文献
912.
为评估非常规油气开采过程水力压裂诱发断层活化失稳风险,基于新库仑稳定函数,通过编程求解诱震概率,分析不同诱因下断层稳定性和失稳风险。结果表明:孔隙弹性剪应力、孔隙压力和差异压实共同作用,是断层活化失稳重要诱因。当孔隙弹性剪应力介于6~10 MPa时,断层失稳概率高达68.9%,其增幅率越大,诱发远区断层失稳风险越高。孔隙压力增量超过3 MPa,对于定向不良断层极为不利;断层倾角和落差越大,差异压实作用越显著。 相似文献
913.
Synergisms between climate change mitigation and adaptation: an insurance perspective 总被引:1,自引:0,他引:1
Evan Mills 《Mitigation and Adaptation Strategies for Global Change》2007,12(5):809-842
As the world’s largest industry, the insurance sector is both an aggregator of the impacts of climate change and a market
actor able to play a material role in decreasing the vulnerability of human and natural systems. This article reviews the
implications of climate change for insurers and provides specific examples of insurance-relevant synergisms between adaptation
and mitigation in the buildings and energy sectors, agriculture, forestry, and land use. Although insurance is far from a
“silver bullet” in addressing climate change, it offers significant capacity and ability to understand, manage, and spread
risks associated with weather-related events, more so today in industrialized countries but increasingly so in developing
countries and economies in transition. Certain measures that integrate climate change mitigation and adaptation also bolster
insurers’ solvency and profitability, thereby increasing their appeal. Promising strategies involve innovative products and
systems for delivering insurance and the use of new technologies and practices that both reduce vulnerability to disaster-related
losses and support sustainable development. However, climate change promises to erode the insurability of many risks, and
insurance responses can be more reactive than proactive, resulting in compromised insurance affordability and/or availability.
Public–private partnerships involving insurers and entities such as the international relief community offer considerable
potential, but have not been adequately explored.
相似文献
Evan MillsEmail: URL: http://insurance.lbl.gov |
914.
Raphael Scheffler Christopher NeillAlex V. Krusche Helmut Elsenbeer 《Agriculture, ecosystems & environment》2011,144(1):281-289
Clearing for large-scale soy production and the displacement of cattle-breeding by soybeans are major features of land-use change in the lowland Amazon that can alter hydrologic properties of soils and the runoff generation over large areas. We measured infiltrability and saturated hydraulic conductivity (Ksat) under natural forest, pasture, and soybeans on Oxisols in a region of rapid soybean expansion in Mato Grosso, Brazil. The forest-pasture conversion reduced infiltrability from 1258 to 100 mm/h and Ksat at all depths. The pasture-soy conversion increased infiltrability from 100 to 469 mm/h (attributed to shallow disking), did not affect Ksat at 12.5 cm, but decreased Ksat at 30 cm from 122 to 80 mm/h, suggesting that soybean cultivation enhances subsoil compaction. Permeability decreased markedly with depth under forest, did not change under pasture, and averaged out at one fourth the forest value under soybeans with a similar pattern of anisotropy. Comparisons of permeability with rainfall intensities indicated that land-use change did not alter the predominantly vertical water movement within the soil. We conclude that this landscape is well buffered against land-use changes regarding near-surface hydrology, even though short-lived ponding and perched water tables may occur locally during high-intensity rainfall on pastures and under soybeans. 相似文献
915.
Set-aside management: How do succession, sowing patterns and landscape context affect biodiversity? 总被引:1,自引:0,他引:1
Teja Tscharntke Péter BatáryCarsten F. Dormann 《Agriculture, ecosystems & environment》2011,143(1):37-44
European Union (EU) member states set aside between 5 and 15% of arable land during the last two decades, but abolition of the set-aside scheme in 2008 caused a sudden loss in habitat availability and biodiversity in agricultural landscapes. Management of set-aside has many facets and in this perspective paper we focus on the biodiversity effects of successional age, sowing strategies and landscape context. Young, 1-2-year-old set-asides have been initially considered to be too ephemeral to have any conservation value. However, when a rich seed and bud bank is available, a species-rich natural (secondary) succession can be observed. Arable (annual) weed communities in the first two years of succession can even include endangered plant species with associated rare insect consumers. Furthermore, many bird species benefit from early-successional habitats, whereas small mammal communities are richer in older habitats. If the local plant species pool is poor, sowings of diverse mixtures from regional seed collections can be recommended. Set-aside managers using species-rich sowings often experience that dominant weeds suppress the less competitive annual species. This trend to species-poor communities can be avoided by intraspecific aggregation of competitively weak species. Broadening the spatial scale from the plot to the landscape, efficiency of set-aside is highest in simple landscapes, where set-aside exhibits greatest effect in enhancement of biodiversity and associated services such as pollination and biological control. In complex landscapes, however, additional set-aside does not add much to the high level of biodiversity and ecological processes already present. Twenty percent of semi-natural, non-crop habitat appears to be a rough threshold for enhancing biodiversity and sustaining services such as pollination and biological control, but improved set-aside management should have the potential to reduce the percentage of semi-natural non-crop habitat needed. EU policy should tailor set-aside schemes for the maintenance of biodiversity and also consider that management efficiency is higher in simple than complex landscapes. 相似文献
916.
917.
Path creation for sustainable consumption: promoting alternative heating systems in Finland 总被引:1,自引:0,他引:1
There are many cost-effective technologies to reduce resource use and carbon dioxide emissions in space heating, yet they are adopted very slowly, and inefficient heating systems persist. In this article, we examine path dependence and path creation in home heating systems. Path dependence refers to the self-sustaining characteristics of existing systems such as the dominant energy system. Path creation is a related concept that highlights entrepreneurship in ‘mindfully deviating’ from existing paths and creating new ones by engaging various stakeholders and generating momentum. Research on path creation in energy systems has focused on energy production systems, whereas end-use technologies have gained less attention. We explore the role of path creation in end-use technologies through four attempts to change heating systems for detached houses in Finland via the promotion of heat pump technologies. Within the path creation process, we focus on how the initiators of new paths try to counter the forces maintaining the dominant system. In particular, we pay attention to how small organizations make use of co-operation to challenge the existing path. The aim is to identify the conditions for successful path creation by entrepreneurs and energy end-users under adverse conditions. 相似文献
918.
Yannay CasasJo Dewulf Luis E. Arteaga-PérezMayra Morales Herman Van LangenhoveElena Rosa 《Journal of Cleaner Production》2011,19(13):1395-1404
The effect of the integration of Solid Oxide Fuel Cell (SOFC) technology in a sugar-ethanol factory on the environmental profile/footprint of the products (sugar, ethanol, electricity) is evaluated. The sugarcane is the primary feedstock and sugar, ethanol and electricity are the main products of the system, where the functional unit is defined as 9.86 ton/h of sugar, 2.195 ton/h of hydrated ethanol (96% w/w) and 847 kWh of electricity. A detailed set of material and energy inputs and outputs was obtained from a local factory and was completed using simulation data by Aspen Plus®.The environmental impacts (greenhouse gases and air pollution), exergy efficiency and a renewability parameter have been considered as indicators for the comparative assessment with conventional sugar, ethanol and electricity production technologies. The results show that the use of a SOFC technology involves a reduction of greenhouse gas emissions (52-55%) and non-renewable resources (60-64%) when compared with the conventional integrated sugar and ethanol plant. The higher renewability index (0.93) and exergy efficiency (38%) are noticed for the Solid Oxide Fuel Cell technology integrated in the sugar-ethanol factory than conventional sugar-ethanol plant. 相似文献
919.
The mercury removals by existing pollution control devices in four coal-fired power plants of China were carried out based on a measurement method with the aluminum matrix sorbent. 相似文献
920.