Diurnal and weekday variations in the source contributions of ozone precursors in California's South Coast Air Basin

For at least 30 years, ozone (O3) levels on weekends in parts of California's South Coast (Los Angeles) Air Basin (SoCAB) have been as high as or higher than on weekdays, even though ambient levels of O3 precursors are lower on weekends than on weekdays. A field study was conducted in the Los Angeles area during fall 2000 to test whether proposed relationships between emission sources and ambient nonmethane hydrocarbon (NMHC) and oxides of nitrogen (NOx) levels can account for observed diurnal and day-of-week variations in the concentration and proportions of precursor pollutants that may affect the efficiency and rate of O3 formation. The contributions to ambient NMHC by motor vehicle exhaust and evaporative emissions, estimated using chemical mass balance (CMB) receptor modeling, ranged from 65 to 85% with minimal day-of-week variation. Ratios of ambient NOx associated with black carbon (BC) to NOx associated with carbon monoxide (CO) were approximately 1.25 +/- 0.22 during weekdays and 0.76 +/- 0.07 and 0.52 +/- 0.07 on Saturday and Sunday, respectively. These results demonstrate that lower NOx emissions from diesel exhaust can be a major factor causing lower NOx mixing ratios and higher NMHC/NOx ratios on weekends. Nonmobile sources showed no significant day-of-week variations in their contributions to NMHC. Greater amounts of gasoline emissions are carried over on Friday and Saturday evenings but are, at most, a minor factor contributing to higher NMHC/NOx ratios on weekend mornings.     

Estimating maquiladora hazardous waste generation on the U.S./Mexico border

Maquiladoras, manufacturing plants that primarily assemble foreign components for reexport, are located in concentrations along the northern frontier of the US/Mexico border. These plants process a wide variety of materials using modern industrial technologies within the context of developing world institutions and infrastructure. Hazardous waste generation by maquiladoras represents a critical environmental management issue because of the spatial concentration of these plants in border municipalities where the infrastructure for waste management is nonexistent or poor. These border municipalities contain rapidly increasing populations, which further stress their waste handling infrastructure capacities while exposing their populations to greater contaminant risks. Limited empirical knowledge exists concerning hazardous waste types and generation rates from maquiladorsas. There is no standard reporting method for waste generation or methodology for estimating generation rates at this time. This paper presents a method that can be used for the rapid assessment of hazardous waste generation. A first approximation of hazardous waste generation is produced for maquiladoras in the three municipalities of Nogales, Sonora, Mexicali, Baja California, and Cd. Juarez, Chihuahua, using the INVENT model developed by the World Bank. In addition, our intent is to evaluate the potential of the INVENT model for adaptation to the US/Mexico border industrial situation. The press of border industrial development, especially with the recent adoption of the NAFTA, make such assessments necessary as a basis for the environmental policy formulation and management needed in the immediate future.     

武汉市马鞍山森林公园夏季鸟类资源及其评价

2005年4—10月调查了武汉市马鞍山森林公园的夏季鸟类资源,共记录鸟类55种,隶属11目24科,其中夏候鸟15种,占27.27%;留鸟40种,占72.73%。有国家Ⅱ级保护鸟类5种,国家保护的有益或有重要经济、科研价值的鸟类43种,湖北省重点保护鸟类23种。对公园夏季鸟类资源进行了评价,并提出了管理建议。     

某氯碱企业液氯泄漏毒害区域危险性评价

针对某氯碱企业液氯贮罐区域潜在的中毒危险性，建立有毒物质泄漏事故后果中毒模型，对其泄漏毒害区域进行了定量分析。     

新生二氧化锰吸附法去除水中直接大红染料

研究了影响新生MnO2对直接大红4B染料废水脱附脱色的有关因素，结果表明，pH是影响脱色效果的关键因素，吸附脱色存在佳化pH范围，其上限随染料浓度的提高和MnO2投加量的增加而增大。投加0．3g/L的MnO2可使染料废水的脱色率达到98．2％，升高温度可提高脱色率。     

APPLICATION OF DIFFUSIVE TANK MODEL IN DRAINAGE ANALYSIS OF PADDY FIELDS1

ABSTRACT: A diffusive tank model has been successfully applied to the simulation of runoff from paddy fields in Japan because it can well describe the features of local water flows. The main goal of the study is to evaluate the performance of the diffusive tank model with the calibrated parameters obtained in Jyau‐Shi to simulate discharge from paddy fields in two experimental catchments located in the areas of Shing‐Ying and Ta‐Liao, Southwestern Taiwan. The simulations were verified by comparing the model results with observed runoff data from the two experimental catchments. The model predicted the discharge from the paddy fields well. This indicates that the model with the calibrated parameters may be used in other paddy fields in Taiwan.     

沈阳市浑河南堤防洪标准的数值模拟计算

浑河原为沈阳南部的一条河流，随着经济的发展，市区扩展迅速，按沈阳市的规划，浑河以南地区不久将发展成为有３０万人口的新区。因此，需在浑河南岸修建堤防，以保护浑南新区不受洪水的危害。但南堤的修建是否会对北岸大堤的防洪安全造成威胁成为防洪规划决策中一个亟待回答的问题。     

GIS在山东省震后早期应急系统中的应用

本文将地理信息系统（GIS）应用于震后早期地震形势判定，地震灾情快速了解，地震监测能力汇总显示等地震应急工作，建立了山东省震后早期地震应急信息系统，实现以历史地震活动信息和地震地质构造背景为基础，以最大概率法给出地震早期形势的判定。同时快速给出震中附近各种历史地震特点，快速给出灾害的影响范围和震区地震监测能力的统计分析结果，为地震早期应急工作提供高显示度的综合信息。     

山西中部地区地震灾害损失预测

简要分析了山西中部的历史地震灾害,用地震安全性评定的综合概率法计算了每个单元遭遇烈度的概率,并对建筑物类型进行分类,根据各类建筑物的易损性矩阵和不同类型单元的人涡震亡率、震伤率矩阵,计算出各个单元建筑物的期望经济损失和人员伤亡期望绝对值,并对计算结果进行了分析和比较。