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241.
• Emissions from two sedans were tested with gasoline, E10 and M15 at 30°C and -7°C. • As the temperature decreased, the PM, PN and BC emissions increased with all fuels. • Particulate emissions with E10 and M15 were more sensitive to the temperature. • The PN and BC generated during cold start-up dominated those over the WLTC. Ambient temperature has substantial impacts on vehicle emissions, but the impacts may differ between traditional and alcohol gasolines. The objective of this study was to investigate the effects of temperature on gaseous and particulate emissions with both traditional and alcohol gasoline. Regulated gaseous, particle mass (PM), particle number (PN) and black carbon (BC) emissions from typical passenger vehicles were separately quantified with gasoline, E10 (10% ethanol and 90% gasoline by volume) and M15 (15% methanol and 85% gasoline by volume) at both 30°C and -7°C. The particulate emissions with all fuels increased significantly with decreased temperature. The PM emissions with E10 were only 48.0%–50.7% of those with gasoline at 30°C but increased to 59.2%-79.4% at -7°C. The PM emissions with M15 were comparable to those with gasoline at 30°C, but at -7°C, the average PM emissions were higher than those with gasoline. The variation trend of PN emissions was similar to that of PM emissions with changes in the fuel and temperature. At 30°C, the BC emissions were lower with E10 and M15 than with gasoline in most cases, but E10 and M15 might emit more BC than gasoline at -7°C, especially M15. The results of the transient PN and BC emission rates show that particulate emissions were dominated mainly by those emitted during the cold-start moment. Overall, the particulate emissions with E10 and M15 were more easily affected by ambient temperature, and the advantages of E10 and M15 in controlling particulate emissions declined as the ambient temperature decreased.  相似文献   
242.
Many state and local agencies have begun to adopt computer technology as a means of upgrading existing mapping and related practices. These agencies are faced with the dualism of wanting modern technology within a traditional setting and demanding technological independence at the same time. This article is an account of the art of technology transfers, with discussions about the necessary ingredients and constraints in the identification, adaptation, absorption, implementation, diffusion, and evaluation of new technologies. In general, a systematic approach towards the strengthening of endogenous capabilities with sufficient provision for operational and policy changes may be preferable to the idea of comprehensive planning.  相似文献   
243.
ABSTRACT: The exact solution for the drawdown in and around a well in a homogeneous, isotropic, and confined aquifer is presented if the well discharge is a function of time. The effect of the storage capacity of the well is also taken into consideration. Two types of flowrate functions are studied, namely linear and exponential functions, and the results are plotted in graphs.  相似文献   
244.
中国石化茂名分公司化工分部于2009年12月27日至2010年1月31日,对2006年新建成投产的2^#裂解装置、2^#加氢装置、芳烃装置、2^#高压装置、2^#聚丙烯装置、高密度装置、2^#丁二烯装置等7套新装置同时安排大检修。 大检修项目有置等7套新装置同时安排大检修。大检修项目有2712项,21家施工队伍进驻厂区,投入施工力量2900多人,面临着任务重、工期紧、安全和质量监管难度大等问题。针对化工装置大检修的特殊性,化工分部对单位员工和承包商检修期间进行绩效考核。  相似文献   
245.
魏莱 《环境科学与管理》2009,34(9):14-16,13
从经济和生态环境的角度分析了当代经济对生态环境的巨大冲击,认为当今经济已逐步发展成一个相对封闭和专门化的系统,它与生态系统有着难以调和的紧张关系,任何经济手段和国家管理行为都无法使经济系统本身衍生出保护生态环境的功能,并且还会受到经济系统的强烈排斥。本文分析了超越发展极限和保持可持续发展所需的条件,认为满足这些条件人类将面临巨大的困难和挑战。  相似文献   
246.
水厂抽水对乌什地震台体应变观测数据的干扰分析   总被引:1,自引:0,他引:1  
根据体应变的观测原理,从理论和实际观测中分析了水厂抽水对体应变观测分钟值曲线的影响及两者间的相关性.分析表明,应变观测值波动时间与抽水时间基本吻合,因此认为水厂抽水对体应变观测会造成一定程度的干扰.  相似文献   
247.
张玉娟  赖纯莹  李友群 《安全》2007,28(7):9-12
近年来,建筑安全生产形势一直比较严峻,重大安全事故呈上升趋势.针对我国建筑业安全事故频繁且对我国建筑业造成严重不良影响的现状,分别建立了市场准入和施工安全监管博弈模型,通过分析上述博弈模型,提出了一些解决办法以降低安全事故发生率.  相似文献   
248.
This study investigated the interaction between Cu2+ and nano zero-valent iron (NZVI) coated with three types of stabilizers (i.e., polyacrylic acid [PAA], Tween-20 and starch) by examining the Cu2+ uptake, colloidal stability and mobility of surface-modified NZVI (SM-NZVI) in the presence of Cu2+. The uptake of Cu2+ by SM-NZVI and the colloidal stability of the Cu-bearing SM-NZVI were examined in batch tests. The results showed that NZVI coated with different modifiers exhibited different affinities for Cu2+, which resulted in varying colloidal stability of different SM-NZVI in the presence of Cu2+. The presence of Cu2+ exerted a slight influence on the aggregation and settling of NZVI modified with PAA or Tween-20. However, the presence of Cu2+ caused significant aggregation and sedimentation of starch-modified NZVI, which is due to Cu2+ complexation with the starch molecules coated on the surface of the particles. Column experiments were conducted to investigate the co-transport of Cu2+ in association with SM-NZVI in water-saturated quartz sand. It was presumed that a physical straining mechanism accounted for the retention of Cu-bearing SM-NZVI in the porous media. Moreover, the enhanced aggregation of SM-NZVI in the presence of Cu2+ may be contributing to this straining effect.  相似文献   
249.
沿海地区电厂温排水在物理、化学、生物等方面对附近海域温度造成的影响越来越受到人们的关注。本文采用现场实测与数值模拟相结合的方法,确定电厂温排水的影响范围,模拟受纳水域的温升分布,评价温排水对海洋生态环境的影响程度,以期为近海海域热污染防治提供技术依据。  相似文献   
250.
寻求行之有效的盐渍化土壤改良措施,对于农业可持续发展具有重要理论和实践意义.采用盆栽试验,探讨了施用硫磺和喷施ALA对碱性盐土上冬小麦(Triticum aestivum L.)和玉米(Zea mays L.)幼苗生长发育及土壤性质变化的影响.结果表明,无论施用石膏、硫磺还是喷施ALA,对于小麦生长均有明显促进作用,其中硫磺效果更为明显;施用硫磺显著提高了后一茬玉米的出苗率,同时土壤中SO42-、Ca2+、Mg2-含量显著增加,但施硫降低土壤pH的作用较为有限;而施用ALA对土壤pH和盐分均无明显影响.这表明施加硫磺可以使盐渍化土壤的性质发生明显改变;ALA的效果则必须在作物苗期生长良好的前提下,通过提高作物自身的抗盐性来实现.  相似文献   
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