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351.
T. I. Moiseenko 《Russian Journal of Ecology》2008,39(6):390-397
A methodological approach to water quality assessment within the scope of the ecosystem health concept is substantiated. Key tasks in water body pollution rating are specified. A rationale for the system of criteria for the diagnosis of aquatic ecosystem health is given on the basis of analysis of determinate changes in their organization levels under anthropogenic stress. The results of testing the proposed methods in water objects of the Volga basin and Lake Imandra are described. 相似文献
352.
Chunyan Liu Witold F. Krajewski 《Journal of the American Water Resources Association》1996,32(2):305-315
ABSTRACT: We compared two interpolation schemes for calculation of hourly accumulation of radar-rainfall. The schemes are: (1) the Advection Method, and (2) the Space-Time Kriging Method. The performance of the methods is investigated using numerical simulation experiments. Space-time evolution of rainfall fields is generated from a stochastic model. The generated fields are sampled following typical radar scanning strategies, and the investigated schemes are applied to obtain accumulated rainfall patterns. The statistical results and a visual analysis of the graphical images suggest that it is advisable to use an interpolation scheme for radar observations even when storm velocity is not high. The Space-Time Kriging Method provides the best results for low wind velocity. The Advection Method has the smallest standard deviation and mean absolute error, and preserves well the true rainfall pattern for high wind velocity. 相似文献
353.
Ahmed Said Mark Ross Ken Trout Jing Zhang 《Journal of the American Water Resources Association》2007,43(2):546-556
Abstract: A nontraditional application of the Hydrological Simulation Program – FORTRAN (HSPF) model to simulate freshwater discharge to upper Charlotte Harbor along Florida’s west coast was performed. This application was different from traditional HSPF applications in three ways. First, the domain of the model was defined based on the hydraulic characteristics of the landforms using small distributed parameter discretization. Second, broad wetland land forms, representing more than 20% of this area, were simulated as reaches with storage‐attenuation characteristics and not as pervious land segments (PERLNDs). Finally, the reach flow‐tables (F‐Tables) were configured in a unique way to be calibrated representing the uncertainty of the storage‐attenuation process. Characterizing wetlands as hydrography elements allows flow from the wetlands to be treated as a stage‐dependent flux. The study was conducted for the un‐gauged portion of the Peace and Myakka rivers in west‐central Florida. Due to low gradient tidal influences, a large portion of the basin is un‐gauged. The objective of this study was to simulate stream flow discharges and to estimate freshwater inflow from these un‐gauged areas to upper Charlotte Harbor. Two local gauging stations were located within the model domain and were used for calibration. Another gauge with a shorter period of record was used for verification. A set of global hydrologic parameters were selected and tested using the parameter optimization software (PEST) during the calibration. Model results were evaluated using PEST and well‐known statistical indices. The correlation coefficients were very high (0.899 and 0.825) for the two calibration stations. Further testing of this approach appears warranted for watersheds with significant wetlands coverage. 相似文献
354.
TERESA P. FERIA ARROYO† MARK E. OLSON‡ ABISAÍ GARCÍA-MENDOZA‡§ ELOY SOLANO† 《Conservation biology》2009,23(5):1156-1166
Abstract: The national systems used in the evaluation of extinction risk are often touted as more readily applied and somehow more regionally appropriate than the system of the International Union for Conservation of Nature (IUCN). We compared risk assessments of the Mexican national system (method for evaluation of risk of extinction of wild species [MER]) with the IUCN system for the 16 Polianthes taxa (Agavaceae), a genus of plants with marked variation in distribution sizes. We used a novel combination of herbarium data, geographic information systems (GIS), and species distribution models to provide rapid, repeatable estimates of extinction risk. Our GIS method showed that the MER and the IUCN system use similar data. Our comparison illustrates how the IUCN method can be applied even when all desirable data are not available, and that the MER offers no special regional advantage with respect to the IUCN regional system. Instead, our results coincided, with both systems identifying 14 taxa of conservation concern and the remaining two taxa of low risk, largely because both systems use similar information. An obstacle for the application of the MER is that there are no standards for quantifying the criteria of habitat condition and intrinsic biological vulnerability. If these impossible-to-quantify criteria are left out, what are left are geographical distribution and the impact of human activity, essentially the considerations we were able to assess for the IUCN method. Our method has the advantage of making the IUCN criteria easy to apply, and because each step can be standardized between studies, it ensures greater comparability of extinction risk estimates among taxa. 相似文献
355.
针对黄土高原地区水资源严重短缺的态势和生态环境建设的需要,以黄土高原典型地区的渭北旱塬为例。对该区各种生态用地降水资源化理论潜力、可实现潜力和现实潜力进行初步估算。并进行相应评价。结果表明:农、林、牧、果业生产结构布局不合理,使得区内各地、市各种降水资源化潜力差异较大;林地、园地、牧草地的自然降水利用率较大:生态用地降水资源化现实潜力开发度与可实现潜力开发度有11.06%差距.现实潜力开发度与理论潜力开发度相比有36.22%潜力尚待开发。证明该区降水资源化潜力较大,但生态环境建设还是受水盗源短缺限制。 相似文献
356.
This study characterizes the compositions of two biodiesel vapors, soy biodiesel and waste cooking oil biodiesel, to provide a comprehensive understanding of biodiesels. Vapor phases were sampled by purging oil vapors through thermal desorption tubes which were then analyzed by the thermal desorption/GC/MS system. The results show that the compounds of biodiesel vapors can be divided into four groups. They include methyl esters (the main biodiesel components), oxygenated chemicals, alkanes and alkenes, and aromatics. The first two chemical groups are only found in biodiesel vapors, not in the diesel vapor emissions. The percentages of mean concentrations for methyl esters, oxygenated chemicals, alkanes and alkenes, and aromatics are 66.1%, 22.8%, 4.8% and 6.4%, respectively for soy biodiesel, and 35.8%, 35.9%, 27.9% and 0.3%, respectively for waste cooking oil biodiesel at a temperature of 25 ± 2 °C. These results show that biodiesels have fewer chemicals and lower concentrations in vapor phase than petroleum diesel, and the total emission rates are between one-sixteenth and one-sixth of that of diesel emission, corresponding to fuel evaporative emissions of loading losses of between 106 μg l−1 and 283 μg l−1. Although diesels generate more vapor phase emissions, biodiesels still generate considerable amount of vapor emissions, particularly the emissions from methyl esters and oxygenated chemicals. These two chemical groups are more reactive than alkanes and aromatics. Therefore, speciation and quantification of biodiesel vapor phases are important. 相似文献
357.
牟勇 《中国安全生产科学技术》2006,2(3):109-111
伤亡赔偿标准由于人的年龄、经历、工作等的不同而不同。本文参考国内外相关资料后,在人人平等的基础上区分了不同人的生命价值,设计的估算方法基本包含了各个年龄段的人的生命价值。估算结果仅适用于事故和不可抗力造成的伤亡情况,不适用于故意伤害谋杀等犯罪活动造成的伤亡。生命价值没有上限只有下限,使生命经济价值的估算值有较大提高,这对提高伤亡赔偿标准,对提高人们对生命价值的认识都有一定的价值。 相似文献
358.
张仁志 《中国环境管理干部学院学报》2001,(2)
本文在对“九五”期间秦皇岛市城市生活、公用事业水情况认真分析的基础上,按秦皇岛市“十五”计划和2010年远景目标对秦皇岛市2005年和2010年未来城市生活需水量和城市公用事业用水量进行了预测;同时对2020年和2030年进行了展望;综合分析预测的结果,提出了节水的建议,并对需水量的零增长期进行了预期分析。本文的研究结果对秦皇岛市水资源可持续利用及国民经济和社会发展规划的制订有积极的意义。 相似文献
359.
针对人体呈现坐姿状态时前侧方作业区域的不同,利用人体测量数据在空间划分网格,实现了上肢作业姿势的参数化定义。并设计实验,由12位健康的男被试参加,利用自由模量幅度估计法对定义过的384种作业姿势的舒适性进行了评价和分级。对依据不同被试个数计算出的结果进行比较分析,并与快速上肢评价方法的评价结果进行比对,揭示了结果的可靠性。评价结果可以为操纵装置的工效设计以及作业空间布局提供重要参考,同时为国内的姿势舒适性评价工作提供了可靠的依据。 相似文献
360.
沙兰镇突发性洪水灾害损失评估及其反思 总被引:4,自引:4,他引:4
我国是洪水灾害频发的国家.本文通过实地调查,对黑龙江省宁安市沙兰镇2005年6月10日突发的洪水灾害损失进行了评估,总结了教训,对防灾、减灾工作进行了反思. 相似文献