FREQUENCY OF DRY DAY SEQUENCES1

ABSTRACT: Data from 100 stations were used to prepare a generalized characterization of the extremely long dry day sequences in the United States. Maps are presented showing the magnitude of the two-year, dry day sequences for 1 mm threshold and the coefficient of variation of the items used in the extreme value analysis. For the United States, the average coefficient of variation for dry periods is 30 percent as compared with that for maximum 24h rainfalls which is 37 percent. An example is presented for computing the longer return periods.     

四川省新型干法水泥行业发展概况及其环境问题分析

本文简述了四川省“十一五”期间新型干法水泥工业发展概况和取得的环境效益,分析了新型干法水泥工业发展中面临的环境问题,提出利用新型干法水泥回转窑处理有机废物和危险废物是今后水泥行业可持续发展的一个重要方向。     

环境试验设备参数测量──盐雾交变试验设备

分析盐雾交变试验设备的功能和实际使用情况,得出其参数测量可依据的相关标准。基于盐雾污染影响干湿球法测量湿度的事实,提示湿度测量时应注意盐雾污染。分析干湿球系数对干湿球法测量湿度的影响和通风速度对干湿球系数的影响,提示对采用自然空气对流恒温恒湿的盐雾交变试验设备的湿度测量,注意干湿球系数A值对湿度测量的影响。同时,对空气自然对流的干湿球湿度表的干湿球系数A值的标定,提出一种简易的方法。     

ASTM D 5894-05《涂漆金属盐雾／紫外线循环暴露标准规程，（交替暴露于喷雾／干燥室和紫外线／冷凝室）》标准解读

介绍了ASTM D 5894—05,分别从标准的适用范围及用途、试验设备、试验样品、试验程序、暴露持续时间和报告等方面对标准进行解读,认为今后的盐雾试验发展方向应向人工试验和自然环境相关性方向发展。     

半干法脱硫配套电除尘器选型分析

某新建135MW机组锅炉为循环化床锅炉,其烟气处理系统采用半干法脱硫工艺加电除尘器。由于半干法脱硫后电除尘器入口的粉尘浓度非常高,且烟尘理化性质发生较大变化,除尘难度大,常规电除尘器的选型很难适应。分析了半干法脱硫后电除尘器选型的影响因素及各系数取值。     

Deposition Velocities of SO2 and O3 over Agricultural and Forest Ecosystems

The results of field studies that measured the flux anddeposition velocity of SO₂ and O₃ are reported. Three of the studies were over agricultural crops (pasture, corn, and soybean), and two were over forest (a deciduous forest and a mixed coniferous–deciduous forest). In all cases the deposition velocity for SO₂ was higher than that for O₃. Diurnal cycles of SO₂ deposition velocity were similar in shape, but not magnitude for all surfaces; however those for O₃ showed some difference between forest sites where the peak was in the morning, and the agricultural sites where the peak occurred at mid-day. Seasonal cycles of SO₂ were affected by deposition to surfaces when leaves were not active, yet surface conductance is significant, but not for O₃ where stomatal uptake is the primary pathway for deposition.(On assignment to the National Exposure Research Lab., US EPA) (e-mail:     

Visual preference and ecological assessments for designed alternative brownfield rehabilitations

This paper describes an integrative method for quantifying, analyzing, and comparing the effects of alternative rehabilitation approaches with visual preference. The method was applied to a portion of a major industrial area located in southern Italy. Four alternative approaches to rehabilitation (alternative designs) were developed and analyzed. The scenarios consisted of the cleanup of the brownfields plus: (1) the addition of ground cover species; (2) the addition of ground cover species and a few trees randomly distributed; (3) the addition of ground cover species and a few trees in small groups; and (4) the addition of ground cover species and several trees in large groups. The approaches were analyzed and compared to the baseline condition through the use of cost-surface modeling (CSM) and visual preference assessment (VPA). Statistical results showed that alternatives that were more ecologically functional for forest bird species dispersal were also more visually preferable. Some differences were identified based on user groups and location of residence. The results of the study are used to identify implications for enhancing both ecological attributes and visual preferences of rehabilitating landscapes through planning and design.     

黑水河干旱河谷沿程土壤物理参数梯度变化特征研究

横断山区干旱河谷是具有典型的旱季和雨季的特殊气候特征的区域,本区域土壤退化和荒漠化极大制约了区域农业的发展。本文研究了金沙江干热河谷区支流黑水河从源头到河口未扰动土壤的物理参数变化特征。结果表明,沿河土壤物理呈现不同变化趋势,砾石在中游部分河段和河口段高,而〉5mm团聚体的变化则相反;5～1mm的团聚体变化不大;〈1mm团聚体河口和源头段高于其余地段;土壤容重沿程增大,非饱和导水率源头地段土壤最高。本研究初步揭示了干旱河谷土壤不均匀,不同水热条件及其组合可能对退化程度有至关重要的影响。这表明横断山区不同的干旱河谷地段土壤和植被退化途径、退化特征和退化过程不同,开发和治理途径与方式也应当不同。     

纤维布袋除尘器高温下干法脱硫研究

论述了高温条件下布袋除尘器中喷入碱性固体物质（Ca(OH)2)脱硫的反应机理。分析了喷射阶段、过滤阶段烟温对脱硫过程发生的各种反应的影响;总结了在布袋除尘器应用不同脱硫剂的脱硫效果。