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本文对盐雾含量和盐雾沉降率的测量与计算进行了详细解析,提出了不同于现行标准的盐雾含量和盐雾沉降率通用计算公式,比较分析了该通用计算公式与现行标准计算公式的差异,分析计算了盐雾沉降率两种常用计算单位的换算倍率,对现行盐雾试验标准的盐雾沉降率进行了分析计算,并对盐雾含量和盐雾沉降率的相互关系进行了分析,最后得到了一些重要的结论。 相似文献
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人工湖因面积较小、流动性差,生态系统极为脆弱,容易产生水体富营养化的问题。本文选取西安某人工湖为研究对象,对其水体水质进行了多参数监测,分析了水质相关指标及季节性变化特征。结果表明:人工湖水质基本能满足Ⅳ类地表水环境质量标准;水体的透明度和溶解氧有明显的季节性变化特征,透明度夏季最低,溶解氧随水温升高而减少,冬季数值最高;pH值、化学需氧量、氨氮随季节没有明显的变化特征,pH值全年呈中性至碱性,处于地表水环境质量标准限制范围(6~9)之内,化学需氧量在2月和3月份值最高;水体中基本没有检测出来石油类和六价铬。 相似文献
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在实验室中模拟松花江水体,研究了在表层沉积物和悬浮颗粒物存在的条件下,铅、镉和铜3种重金属离子在生物膜上竞争吸附的热力学规律。对重金属在自然水体多相体系中的迁移规律进行了探究,以期为重金属污染的治理提供理论依据。 相似文献
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本文对南广河水体中的砷镉铅铬含量分布特征进行了描述,并探讨了南广河的水质质量。结果表明:南广河从上游到了游水体中污染物含量为增大趋势;在时间上也存在一定的变化,枯水期水体中污染物含量高于水期和丰水期。目前南广河综合水质质量可满足Ⅱ类标准要求。 相似文献
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Formula allocation is a major tool for the distribution of public funds in the United States of America. This paper explores several examples of formulae used in U.S. domestic programmes, looking at their construction, meaning and consequences. The authors argue that the design of formulae is both a political and technical task. The paper concludes with a series of recommendations to improve formulae as tools of distributional policy. 相似文献
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Huynh Ngoc Phien Anat Arbhabhirama 《Journal of the American Water Resources Association》1980,16(5):856-861
ABSTRACT: The effects of the selections of plotting position formulae and class division schemes on goodness of fit tests are investigated for the extreme-value type-1 distribution using annual flood and annual maximum daily rainfall data. It was found that the plotting position formulae have a minor influence on the tests which involve their use, while the class division schemes may have a pronounced effect on the X2-test. The study also recommended the maximum likelihood method for fitting purposes and a new test which is independent of the afore-mentioned selections for judging the goodness of fit. 相似文献
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Robert J. Kalter Lois E. Gosse 《Journal of the American Water Resources Association》1974,10(3):498-511
ABSTRACT: The income redistribution effects of waste water treatment grants are estimated for each state participating in five federal programs. Both gross and net effects per state and per capita are discussed. The impact of the tax structure used to finance such grants and the grant formulae are investigated. 相似文献
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本文通过对烟气测试中流速计算公式的比较分析,结合实际监测数据处理,认为烟气流速计算中,使用通用公式与简化公式的误差,虽然与Rs和Bs有关,但主要误差来源于Bs。而Rs不必用精密仪器测出烟气中各组份后求算。只要用简易仪器测得烟气中的Xo2和Xsw的百分含量,即可求出Rs近似值,用于烟气流速计算。 相似文献
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ABSTRACT: A methodology has been developed to predict the responses of a range of water supply sources in Wales to global warming scenarios. Hydrologically effective rainfall is predicted from temperature and precipitation for each season based on site specific formulae developed using the Meteorological Office Rainfall and Evaporation Calculation System (MORECS) and UK Surface Water Archive databases. Comparisons are then made between the effects predicted for the scenarios established from equilibrium simulations and the new Hadley Centre High Resolution Model (UKHI) transient mode results. Though very different, both suggest increased stress on water resources late in the hydrological year. 相似文献
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As a result of the current decline of oil prices, exploration decisions are more carefully analysed than ever before. At the same time various governments have introduced incentives to reinvest in exploration and development in order to maintain or increase activity. As a result, most exploration decisions are now being analysed as "incremental investments". This has the effect of "trapping" investments in areas where profits are currently being made. This in turn creates serious problems for those developing countries which would like to attract exploration. The paper analyses issues related to sliding scale formulae based on the ROR, and the economic impact of the size of the area to which fiscal terms apply. 相似文献
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In this paper, the power output of the cycle is taken as objective for performance optimization of an irreversible regenerated closed Brayton cycle coupled to constant-temperature thermal energy reservoirs in the viewpoint of finite time thermodynamics (FTT) or entropy generation minimization (EGM). The analytical formulae about the relations between power output and pressure ratio are derived with the heat resistance losses in the hot- and cold-side heat exchangers and the regenerator, the irreversible compression and expansion losses in the compressor and turbine, and the pressure drop loss in the piping. The maximum power output optimization is performed by searching the optimum heat conductance distribution corresponding to the optimum power output among the hot- and cold-side heat exchangers and the regenerator for the fixed total heat exchanger inventory. The influence of some design parameters, including the temperature ratio of the heat reservoirs, the total heat exchanger inventory, the efficiencies of the compressor and the turbine, and the pressure recovery coefficient, on the optimum heat conductance distribution and the maximum power output are provided. The power plant design with optimization leads to smaller size including the compressor, turbine, and the hot- and cold-side heat exchangers and the regenerator. 相似文献
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Dennis O’Grady 《Journal of the American Water Resources Association》2011,47(1):39-51
O’Grady, Dennis, 2011. Sociopolitical Conditions for Successful Water Quality Trading in the South Nation River Watershed, Ontario, Canada. Journal of the American Water Resources Association (JAWRA) 47(1):39‐51. DOI: 10.1111/j.1752‐1688.2010.00511.x Abstract: The South Nation River watershed has a regulated water quality trading program. Legally, wastewater dischargers must not discharge any increased loading of phosphorus (P) into receiving waters. New wastewater systems are now choosing trading instead of traditional P removal technology, and point source dischargers are buying P credits from rural landowners, primarily farmers. These credits are generated by constructing nonpoint source pollution control measures. Mathematical formulae are used to calculate the credits of P removed by each measure. A successful trading program requires several conditions, including community agreement, legislative backing, credit and cost certainty, simplified delivery and verification, written instruments, and legal liability protection. South Nation Conservation, a community‐based watershed organization, is the broker handling the transactions for these P credits. The program is run by a multi‐stakeholder committee, and all project field visits are done by farmers and not paid professionals. An independent evaluation showed higher opinions for the broker and regulatory agency, and most farmers were willing to, or had already, recommended the program to other farmers. 相似文献
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D. S. Olsen A. C. Whitaker D. F. Potts 《Journal of the American Water Resources Association》1997,33(6):1197-1207
ABSTRACT: Stream channel stability is affected by peak flows rather than average annual water yield. Timber harvesting and other land management activities that contribute to soil compaction, vegetation removal, or increased drainage density can increase peak discharges and decrease the recurrence interval of bankfull discharges. Increased peak discharges can cause more frequent movement of large streambed materials, leading to more rapid stream channel change or instability. This study proposes a relationship between increased discharge and channel stability, and presents a methodology that can be used to evaluate stream channel stability thresholds on a stream reach basis. Detailed surveys of the channel cross section, water surface slope, streambed particle size distribution, and field identification of bankfull stage are used to estimate existing bankfull flow conditions. These site specific stream channel characteristics are used in bed load movement formulae to predict critical flow conditions for entrainment of coarse bed material (D84 size fraction). The “relative bed stability” index, defined as the ratio of critical flow condition to the existing condition at bankfull discharge, can predict whether increased peak discharges will exceed stream channel thresholds. 相似文献