水泥窑共处置含Cr废物中Cr在不同温度下的形态转化

将Na₂CrO₄加入生料中模拟含Cr入窑物料〔掺加比例为0.048%(以w计)〕,以探索水泥窑共处置含Cr废物过程中Cr的形态转化. 将含Cr入窑物料在不同温度条件下进行煅烧,消解煅烧样品以分析Cr在不同温度下的残留率并利用XANES(X射线吸收近边结构光谱)技术分析煅烧样品中Cr的存在形态. 结果表明:对应900、1000、1100、1200、1300和1450℃煅烧条件下,熟料中Cr的残留率分别为88.2%、70.7%、73.7%、67.2%、69.5%和67.8%. 由于窑尾温度为1050～1100℃,并且Cr的残留率在1100℃较高,因此从窑尾添加含Cr废物可以减少水泥窑共处置含Cr废物过程中的Cr逸放. 在900～1450℃煅烧条件下,所有样品中的Cr主要以CrO₃、Cr₂O₃和CaCrO₄的形式存在. 1000℃煅烧温度下存在K₂Cr₂O₇,但不存在K₂CrO₄;900℃和1100～1300℃煅烧温度下有K₂CrO₄存在,但不存在K₂Cr₂O₇. 1100～1450℃煅烧温度下,Cr元素进入到水泥熟料的主要矿物中,并主要以CrO₃和Cr₂O₃的形式与其他物质结合生成了较为复杂的Ca₄A₁₆O₁₂CrO₄、Ca₆Al₄Cr₂O₁₅等.      

A Management-Orientated Comparative Analysis of Urban and Rural Anglers Living in a Metropolis (Berlin,Germany)

Increased efforts to analyze the human dimensions of anglers are necessary to improve freshwater fisheries management. This paper is a comparative analysis of urban and rural anglers living in a metropolis, based on n = 1061 anglers responding to a mail survey in the German capital of Berlin. More than two thirds of the anglers (71%) had spent most (>50%) of their effort outside the city borders of Berlin and thus were categorized as rural anglers. Compared to the rural anglers, urban anglers (50% of total effort spent inside the city) were younger and less educated. Urban anglers were more avid and committed, less mobile, and more frequently fished from boats and during weekdays. Rural anglers were more experienced, fished for longer times per trip, fished more often at weekends and on holidays, were more often members of angling clubs, and more frequently caught higher valued fish species. The achievement and fish quantity aspects of the angling experience were more important for urban than for rural anglers. Concerning management options, urban anglers more frequently suggested constraining other stakeholders and reducing regulations, whereas rural anglers more often proposed improving physical access to angling sites. Future urban fishing programs should offer ease of access, connection to public transportation, moderate prices, and diverse piscivorous fish stocks. In contrast to rural fisheries, the provision of high ecological and aesthetical quality of the angling waters can be regarded as of minor importance in urban fisheries. Rural fisheries managers need to consider the needs of stakeholders living in Berlin to minimize impacts on the less degraded rural water bodies and potential user conflicts with resident anglers. Ecosystem-based management approaches should guide rural fisheries policy.     

恐怖内心思想的智能阅读车(IRV)开发研究

近年来 ,恐怖袭击事件威胁着城市公共安全 ,给人们的精神和心理造成极大的创伤和痛苦 ,已引起各国政府、各大媒体的广泛关注。笔者分析了城市公共安全的特点 ,研制了恐怖内心思想的智能阅读车 (IRV) ,通过对进入公共场所的人群进行快速 (数秒内 )检测人体生理参数 (3项指标 ) ,阅读人群的心理、生理、行为特征 ,快速地识别出恐怖分子 ,解决了安全预警滞后的问题 ,建立公共安全的常规通道 (或非常规通道 )。研究与开发的目的是从传统的被动防范转变到主动预控 ,为解决国内外防恐和反恐难题提供了一种新方法。     

复合工程系统灾害反应分析与系统控制

防灾工程研究正在循着结构、系统、复合工程系统的轨迹向前迈进。本文综述了复合工程系统灾害反应分析方法与灾场系统控制的研究进展。着重介绍了离散事件动态系统的基本方法及其在复合工程系统地震灾害研究中的应用。指出了这一方向近期内的可能进展。     

Removal of atmospheric particles by leaves and twigs of urban trees: Some preliminary observations and assessment of research needs

This paper reviews the various lines of evidence that support the hypothesis that above-ground plant parts remove particulates from the atmosphere. Some scanning electron microscope observations of the particulate burden on leaves of London planetree are discussed. The authors present an outline of the kinds of research required to support or reject the hypothesis that urban woody plants are important air filters.     

Recreational benefits of residual open space: A case study of four communities in northeastern New Jersey

Numerous undeveloped and ecologically diverse tracts of land within urban communities in the United States are presently being utilized for a variety of unsupervised recreational activities. The present use and perceived value of residual open spaces adjacent to the Palisades to residents of four communities in northeastern New Jersey was assessed. The results of our survey suggest that parks and open space represent a city service that is not as highly valued as other more visible services, that respondents desire a diversity of recreational experiences, that existing parks and open space provide a narrow range of recreational benefits to users, that benefits of existing parks extend primarily to the provision of active pursuits, and that undeveloped residual open spaces are valued for and provide opportunities for a variety of passive pursuits.Residual open spaces are a resource that contributes towards meeting the aesthetic and recreational needs of city residents. Failure by planners and decision-makers to recognize the value and utility of such tracts of land may result in their destruction and in the loss of a resource which provides a range of recreational opportunities that is not adequately provided by formal parks and open spaces.Paper of the Journal Series, New Jersey Agricultural Experiment Station, Cook College, Rutgers University, New Brunswick, New Jersey.This work was performed as a part of NJAES Project No. 17501, Urban Forestry: Planning and Management of Residual Open Space, supported by the New Jersey Agricultural Experiment Station and by a grant from the Consortium for Environmental Forestry Studies sponsored by the U.S. Department of Agriculture, Forest Service, Northeast Forest Experiment Station.     

Natural resource planning: An urban prospective

The use and development of natural resources is becoming a critical concern, especially considering the economic development and stability of the world money market. The question here is one of resources as a political weapon. As resources become more scarce, it becomes necessary to make greater intensive use of resources that are presently available. One dimension that has been missing is the development of urban areas. Resources in this domain have been abused and the question now is how to incorporate these types of decisions into land-use planning to refurbish urban areas. Planning is the key to use of a resource. The world can no longer afford crisis planning. The key dimension to future success in resource problems is preventive planning.     

Erosion control at construction sites on red clay soils

Five single-treatment methods used to stabilize seeded areas at urban and highway construction sites (asphalt-tacked straw, jute netting, mulch blanket, wood chips, excelsior blanket) were tested for their ability to control erosion of red clay soils by comparisons with exposed sites and multiple treatments. Sediment in runoff from experimental plots was characterized during low and high intensity precipitation from natural rainfall episodes during April, May, and June. Reductions in the total sediment concentration of runoff ranged from 28 percent (asphalt-tacked straw, 50 percent slope) to 90 percent (multiple treatments, 40 percent slope), with 85 percent of the eroded material composed of particles <0.04 mm in diameter. Larger size fractions were effectively reduced by all treatments tested regardless of slope (70 percent decrease). Established grass cover exceeded 90 percent on all plots after 60 days, but sediment release remained similar, attributable to high intensity rainfall, poor establishment of root systems, and piping on plots treated with tacked straw or jute netting. Results indicate that current stabilization methods shift sediment compostion toward a smaller particle size, causing single treatments to be minimally effective for controlling erosion of the major component of red clay soils. Because small particles have the greatest direct effect on aquatic biota, certain impacts of sedimentation may not be measurably lessened by single treatments in regions where red clays predominate even though the total sediment load is reduced by as much as 75 percent. Clearly, a multiple-treatment approach offers significantly greater control of erosion on red clay soils, however, current economic and construction policy represents a substantial deterrent to implementation.     

Zone planning régimes

Recent discussion of Enterprise Zones in England has been concerned with attributing development to the financial package of incentives operating, rather than the simplified planning régime, the author reconsiders the question of the significance of the new forms of planning procedure and suggests that, in the long term, the experiment will have lasting significance for the planning system itself.     

Montréal's Eco-quartier environmental program: local action and municipal management

This article assesses the City of Montréal's éco-quartier program from the viewpoint of managing the urban environment and improving living environments. It evaluates the actual achievements of the program, looking especially at the ability of local communities to take effective action to improve their living environments, while under the guidance of the associations mandated to manage the program at the local level. Our research concentrated on three main areas: a) the development of the City of Montréal's environmental program; b) the effectiveness of the éco-quartiers in carrying out their mandate; c) the actual impacts of the program in improving living environments.