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881.
Hydrological influences on the water quality trends in Tamiraparani Basin,South India 总被引:5,自引:0,他引:5
Ravichandran S 《Environmental monitoring and assessment》2003,87(3):293-309
Water quality variables – Turbidity, pH, Electrical Conductivity(EC), Chlorides and Total Hardness (TH) were monitored at adownstream location in the Tamiraparani River during 1978–1992. The observations were made at weekly intervals in a watertreatment and supply plant using standard methods. Graphical andstatistical analyses were used for data exploration, trenddetection and assessment. Box-Whisker plots of annual andseasonal changes in variables indicated apparent trends beingpresent in the data and their response to the seasonal influenceof the monsoon rainfall. Further, the examination of the medianvalues of the variables indicated that changes in the directionof trend occurred during 1985–1986, especially in pH, EC and TH. The statistical analyses were done using non-parametric methods,the ANCOVA on rank transformed data and the Seasonal Man-Kendalltest. The presence of monotonic trend in all the water qualityvariables was confirmed, however, with independent direction ofchange. The trend line was fitted by the method of leastsquares. The estimated values indicated significant increases inEC (28 S cm-1) while significant decreases were observed inturbidity (90 NTU), pH (0.78), and total hardness (23 ppm) in a span of 15 years. The changes induced in river flow by the addition of a stabilizing reservoir, the influence of seasonal and spatialpattern of monsoon rainfall across the river basin and the increased agriculture appear causative factors for the water quality trends seen in the Tamiraparani River system. 相似文献
882.
Estimation of the Soil Respiration Using the Constant Pressure Volumetric Respirometer and the Flow-Through Respirometer UNI-RES10 总被引:1,自引:0,他引:1
Among commonly employed methods of fast estimation of the soil biological activity a method of the oxygen consumption determination is used. The main goal of this research was an estimation of a soil respiratory metabolism using the constant pressure volumetric respirometer and also using the flow-through respirometer UNI-RES10.Soil respiration measurements were done using both types of respirometers in temperatures 10, 15, 20, 25, 30 and 35 °C, keeping up the constant humidity. The investigated soil was a soil humus belonged to organic soils from the Dziekanów Leny field. The soil respiration was also measured for 8 plant communities in Sudeten Mountains with various respiration intensity.After the experiments it was stated that both measuring instruments could be used for the soil metabolism evaluation. Readouts obtained from the UNI-RES10 respirometer are smaller then readouts when using the constant pressure volumetric respirometer. The flow-through respirometers have to be calibrated to obtain results comparable with these from volumetric ones. The volumetric and flow-through respirometry methods are useful for the comparative analysis of metabolism levels. 相似文献
883.
P. A. Bragatto S. Cordiner M. Feola L. Lepore D. Sacco I. Ventrone 《Environmental monitoring and assessment》2000,65(1-2):99-107
Periodogram analysis has been used as an interpretative tool of long period measurements of benzene concentration in urban atmosphere. By removing the request of evenly sampled data, the periodogram allows to extend spectral analysis to this kind of data, which usually suffer the "missing data" problem due to instrument vacancies. In this way it is possible to identify the periodic behaviour of data concentration and then reproduce it by means of harmonic functions even for very incomplete experimental information allowing a good evaluation of some important statistical properties of data. 相似文献
884.
885.
Calmano W 《Environmental science and pollution research international》2004,11(2):126-133
In the preceding series of contributions to ESPR typical examples from actual fields of water chemistry were presented on various topics: integrated water quality management, diagnosis of water bodies, therapy of aquatic systems, and fitness for aquatic systems. These contributions clearly showed the need and importance of more intensive research. In the principle committee III 'Basic Research' of the Water Chemical Society, various expert groups work on scientific backgrounds in these fields. Some relevant topics are selected in this outlook, mainly on interactions of solids with water, the role of environmental colloids, the development of modern biochemical methods for diagnosis, the impact of chemical speciation on bioavailability and water technology, and the development of advanced methods in water treatment technology. Innovative approaches to understand the interactions between pollutants, water and solids are crucial for assessment of contaminants with biochemical and analytical methods, for the development of new efficient technologies and for application of treatment methods with little or no waste and by-product formation. 相似文献
886.
887.
目前,大学英语教学中普遍存在着这样的问题:片面强调词汇及语法知识的教学,而忽略了英美文化背景知识的传授.这就使得学生只会单纯的记忆词汇、分析语法结构,对英美文化知识却知之甚少,从而导致了对文章中出现的与文化有关的内容不理解.为了让同行们认识到这个问题给学生的英语学习所带来的不良影响,笔者从四个方面阐述了大学英语教学中文化渗透的重要性,并对文化渗透的5种方法运用课文中的实例,进行了深入详尽的论述. 相似文献
888.
系统安全分析方法的比较研究 总被引:1,自引:0,他引:1
系统安全分析方法在安全系统工程中占有着重要的地位,是保证生产系统安全运行的基础。当前我国在安全分析方法的使用上仍然存在着很多的纰漏和错误。由于现有的危险性分析方法都有其局限性,一般限于某个或某些行业。为此,在分析之初,分析人员必须对现有的危险性分析方法有一个全面的了解。研究的目的在于通过对各种分析方法的了解和对比,能够全面的把握各种方法的优缺点及适用范围,更好地将理论应用于实际。 相似文献
889.
890.
The debate over snowmobiling and other types of motorized recreation in US national parks signals the need for a better understanding of the meanings of these experiences. The fundamental issue facing many parks is whether snowmobiling is an appropriate activity. The matter of appropriateness is anchored in two questions: (1) Does snowmobiling in national parks cause unacceptable biophysical and social impacts? (2) Are snowmobiling experiences consistent with the fundamental purposes of national parks? This article particularly addresses the appropriateness issue and presents the findings of an interpretive study of the meanings of snowmobiling experiences in Yellowstone National Park (YNP). Sixty-five semistructured interviews were conducted with winter visitors who used snowmobiles in the park during the winter season of 1999. Overall, the study findings reveal that visitors on snowmobiles view YNP as a place to experience its wildland attributes, such as natural scenery, geothermal features, and, especially, wildlife. Snowmobiling is perceived as a mode of transportation rather than the experience in and of itself. The results challenge the popular image of snowmobiles as thrill-craft and snowmobilers as thrill-seekers. The study demonstrates that snowmobiling in YNP affords highly meaningful recreational experiences, grounded in appreciating the park’s unique natural features and attributes. 相似文献