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61.
水厂废水的综合处理与回用是我国供水行业的新趋势和节水目标所在,采用强化混凝技术进行水厂排泥废水的深度处理。通过混凝剂筛选实验和有机物表征确定最佳混凝剂为高效聚合铝(HPAC),适宜投加量为650 mg/L。当混凝剂HPAC投加量为650 mg/L时,对COD、TOC、浊度和色度的去除率分别为82.5%、89.8%、95%和92.5%,相应的出水值分别为58 mg/L、8.46 mg/L、2.35 NTU、13度,COD满足《污水综合排放标准》(GB 8978-1996)的要求(COD≤100 mg/L),同时实验结果显示聚合氯化铝(PAC)、HPAC、三氯化铁(FeCl3)主要去除分子量处于>1 300 Da范围的有机物,对分子量处于744~1 300 Da之间的有机物去除有限。 相似文献
62.
Gonzalo Cortazara 《Resources Policy》2010,35(4):283-291
There is an extensive literature on modeling the stochastic process of commodity futures. It has been shown that models with several risk factors are able to adequately fit both the level and the volatility structure of observed transactions with reasonable low errors. 相似文献
63.
Mekonnen Gebremichael Emmanouil N. Anagnostou Menberu M. Bitew 《Journal of the American Water Resources Association》2010,46(2):361-366
Gebremichael, Mekonnen, Emmanouil N. Anagnostou, and Menberu M. Bitew, 2010. Critical Steps for Continuing Advancement of Satellite Rainfall Applications for Surface Hydrology in the Nile River Basin. Journal of the American Water Resources Association (JAWRA) 46(2):361-366. DOI: 10.1111/j.1752-1688.2010.00428.x. Abstract: Given the increasingly higher resolution and data accessibility, satellite precipitation products could be useful for hydrological application in the Nile River Basin, which is characterized by lack of reasonably dense hydrological in situ sensors and lack of access to the existing dataset. However, in the absence of both extreme caution and research results for the Nile basin, the satellite rainfall (SR) products may not be used, or may even be used erroneously. We identify two steps that are critical to enhance the value of SR products for hydrological applications in the Nile basin. The first step is to establish representative validation sites in the Nile basin. The validation site will help to quantify the errors in the different kinds of SR products, which will be used to select the best products for the Nile basin, include the errors in decision making, and design strategies to minimize the errors. Using rainfall measurements collected from the unprecedented high-density rain gauge network over a small region within the Nile basin, we indicate that SR estimates could be subject to significant errors, and quantification of estimation errors by way of establishing validation sites is critically important in order to use the SR products. The second step is to identify the degree of hydrologic model complexity required to obtain more accurate hydrologic simulation results for the Nile basin when using SR products as input. The level of model complexity may depend on basin size and SR algorithm, and further research is needed to spell out this dependence for the Nile basin. 相似文献
64.
Richard J. Brazee 《中国人口.资源与环境(英文版)》2010,8(3)
Chinese forest resources have become very scarce in the face of rapid economic growth demand, while the reform of collective forest right system is in full swing across the country. It will directly affect the regeneration level of forest resources and the diverse ecological value functions. In this article, the mainstream model paradigm of forest economics, that is, the basic framework of the Faustmann model and its evolution process are made in a more detailed explanation, especially the extended model in... 相似文献
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GIS环境下大区域工程场地地震液化势的二维概率评价方法 总被引:1,自引:0,他引:1
用具有概率意义的饱和砂土抗液化强度经验公式来对大区域场地进行地震液化势二维概率评价;在GIS软件ArcGIS的支持下,将取样钻孔处的液化势评价结果等价于数字高程模型(Digital Elevation Model,DEM)中的高程,利用ArcGIS空间分析模块中的Kriging插值法估计大区域场地的地震液化范围。研究表明:将Kriging法应用于岩土工程地质特征的统计推断,有助于揭示勘探孔以外的地层信息,对于大区域场地地震液化范围的判别是一个较好的手段;利用ArcGIS空间分析模块中的Kriging法,通过已勘察点的信息(液化势)来估计未勘测点的土层液化势,能够较好地区划出场地地震液化势的空间分布特征。 相似文献
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Karline SoetaertMarilaure Gregoire 《Ecological modelling》2011,222(12):1929-1942
Oxygen (O2), nitrate (NO3), dissolved inorganic carbon (DIC) or pCO2, and pH or total alkalinity (TA), are useful indices of marine chemical, physical and biological processes operating on varying time-scales. Although these properties are increasingly being monitored at high frequency, they have not been extensively used for studying ecosystem dynamics. We test whether we can estimate time-evolving biogeochemical rates (e.g. primary production, respiration, calcification and carbonate dissolution, and nitrification) from synthetic high frequency time-series of O2, NO3, DIC, pCO2, TA or pH. More specifically, a Kalman filter has been implemented in a very simplified biogeochemical model describing the dynamics of O2, NO3, DIC and TA and linking the concentration data to biogeochemical fluxes. Different sets of concentration data are assimilated and biogeochemical rates are estimated. The frequency of assimilation required to get acceptable results is investigated and is compared with the frequency of sampling in the field or in controlled experimental settings.Smoothing of the data to remove data noise before assimilation improves the estimation of the biogeochemical rates. The best estimated rates are obtained when assimilating O2, NO3 and TA although the assimilation of DIC instead of TA also gives satisfactory results. In case pH or pCO2 is assimilated rather than DIC or TA, the linearization of the (now nonlinear) observation equation introduces perturbations and the Kalman filter behaves suboptimal. We conclude that, given the resolution of data required, the tool has potential to estimate biogeochemical rates of the carbonate system under controlled settings. 相似文献
70.
ABSTRACT: A climate factor, CT, (T = 2–, 25-, and 100-year recurrence intervals) that delineates regional trends in small-basin flood frequency was derived using data from 71 long-term rainfall record sites. Values of CT at these sites were developed by a regression analysis that related rainfall-runoff model estimates of T-year floods to a sample set of 50 model calibrations. CT was regionalized via kriging to develop maps depicting its geographic variation for a large part of the United States east of the 105th meridian. Kriged estimates of CT and basin-runoff characteristics were used to compute regionalized T-year floods for 200 small drainage basins. Observed T-year flood estimates also were developed for these sites. Regionalized floods are shown to account for a large percentage of the variability in observed flood estimates with coefficients of determination ranging from 0.89 for 2-year floods to 0.82 for 100-year floods. The relative importance of the factors comprising regionalized flood estimates is evaluated in terms of scale (size of drainage area), basin-runoff characteristics (rainfall. runoff model parameters), and climate (CT). 相似文献