基于轮廓似然函数的PM_(10)极值浓度分析

以R软件为分析工具,选择GEV(generalized extreme value distribution)模型拟合四川省泸州市2003～2007年期间PM10每月最高日平均浓度数据,采用极大似然法估计模型的3个参数即位置参数、尺度参数、形状参数,利用所得的参数估计值计算得出某一标准值(如GB3095—1996)的重现期;进一步利用参数估计值计算轮廓似然函数,估计某一段固定时间间隔的PM10浓度的重现值以及其置信区间。结果表明,GEV模型能很好地拟合泸州市PM10数据,利用轮廓似然函数估计的不同时间间隔的重现值准确度高,统计结果可以为环境主管部门发布污染状况预警信息提供参考。     

Emergy analysis using US economic input-output models with applications to life cycles of gasoline and corn ethanol

A commonly encountered challenge in emergy analysis is the lack of transformity data for many economic products and services. To overcome this challenge, emergy analysts approximate the emergy input from the economy via a single emergy/money ratio for the country and the monetary price of economic inputs. This amounts to assuming homogeneity in the entire economy, and can introduce serious uncertainties in the results. This paper proposes and demonstrates the use of a thermodynamically augmented economic input-output model of the US economy for obtaining sector-specific emergy to money ratios that can be used instead of a single ratio. These ratios at the economy scale are more accurate than a single economy-wide emergy/money ratio, and can be obtained quickly for hundreds of economic products and services. Comparing sector-specific emergy/money ratios with those from conventional emergy studies indicates that the input-output model can provide reasonable estimates of transformities at least as a stop-gap measure until more detailed analysis is completed. A hybrid approach to emergy analysis is introduced and compared with conventional emergy analysis using life cycles of corn ethanol and gasoline as examples. Emergy and transformity data from the hybrid approach are similar to those from conventional emergy analysis, indicating the usefulness of the proposed approach. In addition, this work proposes the metric of return on emergy investment for assessing product alternatives with the same utility such as transportation fuels. The proposed approach and data may be used easily via web-based software.     

Assessment of grate sag inlets in a residential area based on return period and clogging factor

Storm in-sag inlets, which typically have inflow capture efficiency of 100%, can violate the allowable water spread criterion of roadways, thus slowing the traffic movement and contributing to accidents. This is especially evident during severe storms of high return periods and when a storm sewer inlet of grate type is adopted, because it is subject to debris and trash clogging factors. In this study, the water spread on pavement for in-sag grates located in a residential area in Kuwait is analyzed in terms of return period and clogging factor. It is found that for a single grate inlet with a return period of 10 years, a clogging factor of 50% can lead to a water spread value exceeding the local design constraint assigned for residential areas, which is one traffic lane of 4m width. It is also shown that for in-sag locations, a double-grate inlet is more preferable than the single one, because the former tends to reduce the adverse hydraulic effect of total inflow on water spread width. The effect of clogging factor on a multiple-grate inlet located in sag is determined from a simple expression suggested in this study.     

城市火险天气等级多因子综合预报法

在“城市火灾中关键气象因子的诊断分析”的基础上,通过权重系数法四季城市火灾率多因子综合预报法,     

龙江县景星镇十年退耕还林生态影响分析

退耕还林工程是我国生态环境保护建设的一项重大措施,景星镇从2002年实施退耕还林工程以来,森林覆盖率显著提高,生态环境明显变化。主要表现在:水土流失得到有效控制、土壤有机质提高,土壤肥力得以修复;林地涵养水源、固碳释氧的功能得到发挥,生境改善,生物多样性恢复。     

Return delays and evacuation order compliance: the case of Hurricane Georges and the Florida Keys

Abstract

Using interview data, we examine the effects of the heavily publicized delays in reentering the Florida Keys after Hurricane Georges on future evacuation intent. Of particular interest is the finding that the delays will have less influence on the future evacuation decisions of those who experienced them than on those who learned of them from secondary sources. Fear of return delays is only one factor in evacuation decision-making, albeit an understudied one. For this sample of evacuees, perceived risk is the most salient factor, and this risk assessment is not sufficiently diminished by the inconveniences, such as delays, associated with evacuation. For non-evacuees, however, the delay factor appeared to only increase their reluctance to evacuate the next time, despite their level of perceived risk.     

日光型厌氧好氧一体化技术处理滨海农村污水

对日光型厌氧好氧一体化技术处理农村生活污水的效能进行了应用研究。系统的处理量为89t/d,HRT为1.8 d,水解酸化段水力负荷为0.78 m3/(m3·d),接触氧化段水力负荷4.24 m3/(m3·d),稳定运行6个月结果表明:该工艺对CODcr、NH3-N 、TP和SS的去除率分别为73.2%、49.5%、56.1%和79.3%,出水 CODcr、NH3-N、TP、SS的平均浓度分别在60.3 mg/L、20.4 mg/L、2.7 mg/L、26.7 mg/L以下出水水质达到GB18918-2002要求。     

乙烯排海废水深度处理及回用研究

茂名石化乙烯公司排海废水水质较好，远低于国家排放标准。经过深度处理后，水质可达到回用水要求。再进一步通过挂片腐蚀试验、杀菌试验和动态模拟试验，证明了乙烯排海废水能回用做循环水补充水。     

气提系统的运行特性

采用清水和空气作为介质,利用实验室条件下冷态模拟气提系统。试验结果表明在通气量一定时,随着回水流量的增大,水的压差逐渐降低。当回流水量相同时,压差随着通气量的增大而升高。气含率随着表观气速的增大而增大。