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61.
Y. Dubuc P. Janneteau R. Labont C. Roy F. Brire 《Journal of the American Water Resources Association》1986,22(2):297-303
ABSTRACT: The use of peatlands as the main form of wastewater treatment in a northern climate was studied for the James Bay Energy Society. The Fontanges campsite (70° 17′ 30″ W; 54° 34′ 00″ N) was chosen as the study site. In less than 1.5 km from the point of discharge BOD5, COD, total hardness, inorganic carbon, orthophosphates, total phosphorus, ammonia and total nitrogen were reduced by at least 90 percent. The peatland treatment system studied is divided into four components, each having a specific function. The first part combines the action of microorganisms and adsorption on peat, thus reducing the organic content while increasing the inorganic constituents. The second part uses peat to adsorb the inorganic elements already present in the wastewater and those produced in the first part of the system. The third component acts as an aerator, increasing the dissolved oxygen and decreasing the BOD5 levels of the water. The fourth part removes most of the remaining nutrients, thus acting like a tertiary treatment. Overall, peatlands seemed to be effective in treating domestic settled wastewater in a cold climate. 相似文献
62.
气象灾害的研究和预防是野外职业安全卫生的一个重要领域 总被引:1,自引:0,他引:1
从事野外地质勘探的职工常常处于大自然环境中。自然环境灾害(气象灾害、地质灾害等)是造成地质勘探职业伤害的重要原因之一。在诸多的环境灾害中,又以气象灾害的危害最为突出。研究和预防气象灾害,是地质勘探安全卫生工作的重要内容。如果只研究人为职业伤害(一般工业安全卫生中的主要问题),而不研究环境灾害,特别是气象灾害所造成的事故和职业病,那是舍本求末。在地质勘探安全卫生领域中,研究气象灾害及其防护技术,既是保护野外作业职工安全和健康的需要,也是拓宽安全科学外延领域的有益探讨。 相似文献
63.
64.
Four satellites have been used in meteorology. They are TIROS, ESSA, Nimbus, and Applications Technology Satellite (ATS). The first three operate in the orbital altitudes of about 1000 to 1200 km while the fourth, ATS, is at geosynchronous altitude of 36,000 km. Cloud cover is being observed operationally from low orbit and experimentally from synchronous altitude. Wind velocity has been inferred from the frequent cloud cover pictures taken by ATS and satellite-balloon systems are being developed which will locate and track constant-density level balloons for determining wind flow. Spectrometers and radiometers operating in the electromagnetic spectral region from the ultraviolet to the microwave region are being developed to quantitatively measure temperature, water vapor, density, and wind profiles. These will furnish data for the development and testing of atmospheric models for numerical prediction. In addition, experiments are being developed to measure ozone and other constituents of the air, solar energy, surface conditions, heat balance and other atmospheric attributes which affect the structure and dynamics of the atmosphere. 相似文献
65.
概述了青岛市基础设施现状; 介绍了青岛市主要自然灾害(气象、地震) 特别是90 年代以来重要灾情, 并分析了特征; 最后给出了结论和建议。 相似文献
66.
David V. MacDonald Kline P. Barney Shelley F. Jones 《Journal of the American Water Resources Association》1977,13(3):583-598
ABSTRACT: This paper describes a method of analyzing the nonquantifiable parameters which should be considered in the evaluation of engineering alternatives. The nonquantifiable parameters can include environmental impact, feasibility of implementation, and performance. The method considers rating all the alternatives on the basis of a set of criteria which reflect these parameters. A procedure is discussed for obtaining review and guidance in the evaluation of engineering alternatives from the local elected officials or governing bodies and for obtaining the views and desires of the local communities. This is achieved through the formation of project review committees and an evaluation procedure which allows for the technical rating of alternatives by the engineer and the weighing of the evaluation criteria by the political and social groups. With the growing environmental concern and the high cost of engineering projects, the involvement of the public during the evaluation of engineering projects is becoming increasingly important to the final success of the project. 相似文献
67.
Most of the mesoscale models use roughness parameters to characterise the ground and to compute the surface stress. As the experimental determinations of the urban roughness parameters are rare and not very reliable, a new methodology based on microscale numerical simulations is presented here and the first results from two-dimensional simulations with different roof shapes are analysed.Firstly, it appears that the roof shape has a large influence : large difference in the Reynolds stress profile and in the roughness sub-layer thickness, enhancement of the exchanges at the roof level by buildings with attic. It also appears that the fetch necessary to obtain a constant flux layer is unrealistic compared to the real spatial homogeneity of quarters in European cities. Consequently, a new parameterisation of the urban ground-induced friction is to be developed without reference to the constant flux layer theory. 相似文献
68.
聚能药包在岩石控制爆破技术中的应用研究 总被引:1,自引:0,他引:1
罗勇 《防灾减灾工程学报》2007,27(1):57-62
聚能爆破技术是岩石控制爆破技术中有待开发的领域。根据爆炸力学、岩石断裂力学理论,从当前控制爆破面临的问题入手,对线性聚能药包(Linear shaped charge)在岩石定向断裂爆破中裂纹的产生、扩展以及主要爆破参数进行了分析研究,并利用自制线性聚能药包在巷道掘进中进行了试验。试验结果是聚能药包形成的巷道轮廓外爆震裂隙不明显,巷道断面平整,凹凸量不超过50mm,眼痕率高达96%以上,经济和社会效益明显。这些均表明聚能爆破是一种理想的定向断裂控制爆破技术。 相似文献
69.
Majagi SH Vijaykumar K Vasanthkaumar B 《Environmental monitoring and assessment》2008,138(1-3):273-279
In this study, some heavy metals concentrations (Zn, Pb, Fe, Mn, Cu, Ni) and other physico-chemical parameters were studied
during October 2001 to September 2003 in Karanja reservoir, Bidar district. Water quality parameters were collected monthly
basis whereas heavy metals were analyzed by Atomic Adsorption Spectrometer (AAS). Heavy metals have shown within the permissible
limits, except Fe and Ni were recorded higher values in southwest monsoon, where as Mn has showed higher concentration in
northeast monsoon in and summer. All other physico-chemical parameters are with in the permissible limit. Water is moderately
hard and reservoir is productive. 相似文献
70.
In Europe, the use of direct methods using lysimeters for measuring water and solute flow in soils increased in recent years.
Large weighable lysimeters are best suitable for obtaining reliable data about seepage water quantity and quality. Field lysimeters
– lysimeters built in directly in agriculturally used areas – of high technical standard allow a precise determination of
the influence of different cropping systems on groundwater quality. They combine the advantages of true field conditions and
laboratory possibilities of varying parameters, handling and maintenance. Due to the specific needs of each application the
instrumentation varies. Based on general remarks on the advantages of precise weighing lysimeters four standardized lysimeter
configurations are presented. Beside the specific needs of design and setup of lysimeter stations, there is need to define
general requirements to enable comparable results based on standardized basic design and to reduce individual mistakes. 相似文献