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121.
DDS系列煤炭自燃阻化剂实验研究   总被引:11,自引:0,他引:11  
童希琳 《火灾科学》1997,6(1):20-26
为寻找高效阻化剂以防止煤炭自热引燃,在控温炉中对DDS系列煤自燃阻化剂的阻化效果进行了实验研究,并与经前的阻化剂做了比较。实验采用烟煤作为试样,借助于著名的Frank-Kamenetskii模型,利用4,6,8和10厘米立方体阻化煤磁地60-220℃温度范围估测其氧化反应的活化能。  相似文献   
122.
ABSTRACT: Aquifers with pressure head seriously reduced by overdrafting are referred to as depleted. In coastal areas they may be invaded by saltwater. An obvious remedy is to reduce the rate of withdrawal to the permanently available dependable yield. This is being done now in two areas for New Jersey, under the authority of the State's Water Supply Management Act; but it has not previously been accomplished on a regional scale. The dependable yield was estimated by means of detailed hydrogeological modeling. “Water Supply Critical Areas” were delimited on the basis of piezometric pressure, drawn down 30 feet below sea level. Within the depleted area, water withdrawals must be reduced by a fixed ratio (35 to 50 percent) below the amount withdrawn during 1983. This reduction is effective as soon as al alternative source of water can be made available, usually from a surface source. Special arrangements are made whereby ground water users unconnected to the alternative source of supply can pay to withdrawn their full needs from the depleted aquifers, the money being used to purchase additional water from the new surface water source, in return for which some other user will reduce his ground water withdrawal below his reduced allocation.  相似文献   
123.
The lakes in KillarneyProvincial Park, located 40–60 km southwest ofSudbury, Ontario, were some of the first lakesin North America to be acidified by atmosphericpollutants. Acidification affected thousandsof fish and invertebrate populations in dozensof lakes. Since the 1970's, water quality hasimproved in response to atmospheric pollutionreductions and some lakes have alreadyrecovered to approximately their pre-industrialpH levels, as inferred from diatom microfossilsin lake sediments. Since the 1970's, fishspecies richness has not changed substantially,but zooplankton species richness has increasedin acidified lakes. The critical sulphur load,the amount of SO2-derived acid depositionthat can occur while still maintaining suitable water quality, was estimated to beexceeded in 38% of the park area in 1997. Depending on which of four possible NorthAmerican emission control scenarios (CLR =currently legislated reduction; CLR + 25%; CLR+ 50%; CLR + 75%) is achieved by 2010, theprojected critical loads will be exceeded inabout 0-30% of the park area in the future. There are many factors that can affectbiological recovery rates of damaged lakes, butit is expected that biological recovery willlag considerably behind observed chemicalrecovery rates.  相似文献   
124.
以机动车排放颗粒物采集和分析为主要目的,开发了全流稀释风道机动车排放颗粒物采集系统.文章阐述了全流稀释风道的系统集成以及流量控制系统的设计和调节,其中包括设计应用范围、主要技术参数、系统检定等.流量控制系统采用的关键技术,即文丘里管组合装配方式具有控制流量范围广、变更灵活的特点,可以适应小到摩托车,大到重型柴油车等不同类型车辆检测的需要.  相似文献   
125.
铁路汛期行车安全对策——雨量警戒制度研究   总被引:4,自引:0,他引:4  
雨量警戒制度是铁路部门用于指导进行汛期警戒 ,确保线路汛期行车安全的一种安全保障制度 ,由警戒标准、防御标准和管理制度 3部分组成。它是一种分级、分段和各工种联控执行的警戒制度 ,其技术关键包括警戒标准和防御标准的制定。本文提出了雨量警戒制度警戒标准的指标体系 ,建立了警戒标准的制定方法与工作程式 ,并以成昆铁路雨量警戒制度的制定与实施说明了其应用。所提方法对铁路部门制定汛期行车安全对策具有普适意义。  相似文献   
126.
In order to resolve the spatial component of the design of a water quality monitoring network, a methodology has been developed to identify the critical sampling locations within a watershed. This methodology, called Critical Sampling Points (CSP), focuses on the contaminant total phosphorus (TP), and is applicable to small, predominantly agricultural-forested watersheds. The CSP methodology was translated into a model, called Water Quality Monitoring Station Analysis (WQMSA). It incorporates a geographic information system (GIS) for spatial analysis and data manipulation purposes, a hydrologic/water quality simulation model for estimating TP loads, and an artificial intelligence technology for improved input data representation. The model input data include a number of hydrologic, topographic, soils, vegetative, and land use factors. The model also includes an economic and logistics component. The validity of the CSP methodology was tested on a small experimental Pennsylvanian watershed, for which TP data from a number of single storm events were available for various sampling points within the watershed. A comparison of the ratios of observed to predicted TP loads between sampling points revealed that the model's results were promising.  相似文献   
127.
酸化模型及其在确定酸沉降临界负荷中的应用   总被引:18,自引:4,他引:14  
简述了国外近10年来在酸沉降影响研究中,为预测酸沉降对土壤、地表水、地下水和湖泊的长期影响而开发的各种酸化模型,经比较分析,归纳出建立这此匠基本方法及应用于确定酸沉降临界负葆的基本原理。  相似文献   
128.
In January 2016, armed militants occupied the Malheur National Wildlife Refuge, demanding an end to government control of the Refuge and other similarly protected public lands. Public discourse about the occupation highlights ongoing tensions around land use, property rights, and government overreach. The discourse foregrounds human animal concerns and all but erases nonhuman animal agency. This essay considers nonhuman animal agency and the entanglement of humans, nonhumans, and the land as seen in the occupation and surrounding discourse. We draw from critical animal studies and feminist posthuman theory to examine how discourses of the occupation produce and reinforce a sense of human exceptionalism that elides a more useful and nuanced understanding of human–nonhuman–land relatedness and agency. The analysis shows how, in the case of the Malheur occupation, occupiers and critics alike rely on discourses of “othering” towards both nonhuman animals and other humans. We take a “birding” perspective on the occupation to show how the webs of relationality that connect humans, nonhumans, and the land might be activated as an antidote to destructive discourses of human exceptionalism.  相似文献   
129.
为研究不同供风量对褐煤自燃特性的影响规律,选取平庄瑞安煤矿褐煤作为试验煤样,利用程序升温试验和气相色谱仪,研究低温氧化阶段不同供风量条件下褐煤自燃极限参数与温度、供风量之间的变化规律。结果表明:温度在40~120℃时,随着供风量增大,褐煤的最小浮煤厚度和下限氧浓度降低,上限漏风强度增加;温度在120~200℃,供风量为40~80 mL/min和160~200 mL/min时,随着供风量的增加,其最小浮煤厚度和下限氧浓度增加,上限漏风强度减少;供风量为80~160 mL/min时,在供风量增大的情况下,褐煤的最小浮煤厚度和下限氧浓度降低,上限漏风强度增加;随着供风量减小,煤样临界点温度降低。  相似文献   
130.
关键基础设施(CI)是维持社会大系统正常运行的重要组成部分,是复杂的网络巨系统,而CI抗灾能力评估指标需具有系统性、客观性和一致性。案例驱动与数据驱动在能力评估指标选择中各有优势,亦相互支持。依靠案例驱动,可以把握历史经验,引导CI抗灾能力评估的情景设计及全局指标选择改进;借助数据驱动,可以发现潜在的微观指标,通过数据分析引导抗灾能力评估微观指标体系改进与完善。集成这2种评估驱动方法,提出CI抗灾能力评估指标选择的案例-数据集成驱动框架,并结合用例验证评估方法的有效性。  相似文献   
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