Response Surface Modeling and Optimization of Microwave‐Activated Persulfate Oxidation of Olive Oil Mill Wastewater     

Nevim Gen  Elif Durna  Hatice Kübra Kayapinar Cicigün 《洁净——土壤、空气、水》2020,48(1)

Olive oil mill wastewater (OMW) is environmentally hazardous not only because it contains high recalcitrant and toxic compounds, but also due to its high organic load and turbidity. In this study, oxidation of OMW by microwave (MW)‐activated persulfate is investigated. Box–Behnken design is applied to investigate the effects of operating conditions on operating cost, organic matter, and color removal. Multi response optimization is performed according to minimum operating cost, maximum organic matter and color removal efficiencies. At optimum conditions (persulfate anion dose of 266 g L^?1, oxidation duration of 23.58 min, MW power of 567 W, and initial pH 2), chemical oxygen demand (COD) removal of 63.38%, color removal of 94.85%, and operating cost of 0.0633 Euro/g total organic carbon (TOC) removal are found. The biochemical oxygen demand (BOD₅)/COD ratio is increased from 0.144 to 0.285. Results of Pareto analysis show individual effect of MW power is 92.81% for TOC removal, 15.52% for color removal, 68.99% for operating cost, respectively. According to the results, it is not recommended to use this process as an ultimate treatment unit due to the high amount of oxidizing agent consumed. Instead, it is recommended to be used as a pre‐ or post‐treatment step.  相似文献   

中国国土面积究竟有多大?——标度对称与中国陆地面积的分形分析     

陈彦光 《地理研究》2012,31(1):178-186

海岸线的长度依赖于测量尺度,因此没有确定的测量结果:尺度越小,测量的长度值越大。国境线的测量也具有类似的尺度依赖性。这种性质与分形性质有关。分形的本质是标度对称性,而对称性意味着某种不可观测量。由于标度对称性的存在,一些地理现象的基本测度(如长度、面积)无法准确计算。中国、美国等国家的国土面积大小都没有确切的数据:在版图没有任何变动的情况下,不同时期、不同机构的测量结果不一致,有时甚至大相径庭。本文借助分形模型和标度对称思想探讨这一问题。假定一个国家包括漫长的海岸线,则其国土可以分解两部分:主体部分可以用Koch岛模型刻画,岛屿部分则可以用Pareto分布描述。这两部分叠加的结果是,国土总面积随着测量尺度的减少而逐步增加。因此,中国政府可以正式公布国土面积的最新测量数据,而不必继续担心由此引发的国际政治争端。  相似文献   

海洋重现期波高统一化计算方法     

尤再进 《海洋与湖沼》2022,53(4):1015-1025

重现期波高是港口海岸及海洋工程设计中不可回避的一个重要设计参数,尤其对深水海港、海上平台、海底油气管道、沿海核电站等重大涉海工程设计具有巨大的经济价值和深远的社会效益。但是,现有重现期波高推算缺乏统一的计算方法,导致计算结果相差悬殊。研究重现期波高的统一化计算方法,分析重现期波高计算中存在的各种不确定因素,提出减少这些不确定因素的新方法,建立误差小、应用方便、方法统一的重现期波高计算方法。基于澳大利亚悉尼站的长期连续观测波浪数据,研究发现:广义帕累托函数(generalized Pareto distribution III,GPD-III)和威布尔(Weibull)是重现期波高计算的最佳候选极值分布函数,新推导的函数形状参数计算公式较好提高重现期波高的计算精度,极值波高数据的分析方法和样本大小是影响重现期波高计算精确度的两个重要因素,短期波浪资料和年极值法可能高估重现期波高值。逐个风暴的极值波高数据分析法及最佳候选极值分布函数GPD-III和Weibull建议应用于涉海工程设计的重现期波高推算。  相似文献   

雷达回波预测极端暴雨概率方法构建原理与应用研究   总被引：2，自引：0，他引：2  

王坚红  黄维  王群  苗春生  张志刚  徐良谋 《高原气象》2015,34(2):575-585

基于局地雷达回波基数据强度与雷达体扫面内相应地区强降水量之间的统计关系,并通过LucasKanade局部光流法分析下一小时可能影响该地区的回波区域,将这些区域定义为强降水影响系统的动态回波上游。同时分析雷达各层体扫回波情况,即考虑强降水系统的空间伸展程度。通过分析这些动态回波区域在当前时刻内(每10 min多层体扫信息)的时空变化特征,建立回波强度特征与局地降水的相关,进一步与改善的降水极值概率预测方法相结合,构建对下一小时局地暴雨重现期极值预测预警指标,为应急保障方案和及时应对决策提供技术支持与专业参考信息。整体方案以2006-2011年6-8月盐城多普勒天气雷达回波强度的基数据资料和同时段盐城雷达体扫范围内建湖气象站的小时雨量序列为基础,采用Lucas-Kanade局部光流法确定回波强度反映的降水系统时空动态上游,并利用皮尔逊III型方法和广义帕累托方法建立回波类别与建湖局地白天与夜间降水序列的统计概率关系,计算回波类别对应的局地极端降雨极值以及极值重现概率特征,构建降水系统的雷达回波动态综合特征与下一小时局地强降水极值概率间的统计关系指标,指标的相关性检验达到70%。该方法具有强降水多等级重现期极值预测能力,为下一小时临近极端暴雨预测预警提供了雷达监测动力统计优化方法。  相似文献   

The generalized Pareto sum     

Saralees Nadarajah  Samuel Kotz 《水文研究》2008,22(2):288-294

The generalized Pareto distribution has received much popularity as models for extreme events in hydrological sciences. In this note, the important problem of the sum of two independent generalized Pareto random variables is considered. Exact analytical expressions for the probability distribution of the sum are derived and a detailed application to drought data from Nebraska is provided. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

广义帕雷托分布在波浪极值推算中的应用     

韩树宗  刘昆 《中国海洋大学学报(自然科学版)》2014,44(4):1-7

以CCMP风场(1988年1月~2010年12月)为驱动,本文采用第三代海浪数值模式SWAN对中国海海区进行风浪场的数值模拟,并利用浮标资料对驱动风场和计算有效波高进行验证。根据模拟的结果分别采用广义帕雷托分布(GPD)和常用的广义极值分布(GEV)拟合累积频率曲线并进行效果检验,进而分析和比较2种分布的优缺点,并运用广义帕雷托分布(GPD)模型进行重现期波要素的推算,分析GPD模型的应用前景。  相似文献   

Construction of Intensity–Duration–Frequency (IDF) curves for precipitation at Lubumbashi,Congo, under the hypothesis of inadequate data     

Hans Van de Vyver  Gaston R. Demarée 《水文科学杂志》2013,58(4):555-564

Abstract

Intensity–Duration–Frequency (IDF) curves for precipitation constitute a probabilistic tool and have proven useful in water resources management. In particular, IDF curves for precipitation enable questions on the extreme character of precipitation to be answered. The construction of IDF curves for precipitation is difficult or impossible in tropical areas due to the lack of long-term extreme precipitation data. A technique is proposed to overcome this shortcoming by combining limited high-frequency information on rainfall extremes with long-term daily rainfall information. It may be regarded as an extension of Koutsoyiannis' approach. Using this technique, IDF curves for precipitation are produced for Lubumbashi in Congo.

Citation Van de Vyver, H. & Demarée, G. R. (2010) Construction of Intensity–Duration–Frequency (IDF) curves for precipitation at Lubumbashi, Congo, under the hypothesis of inadequate data. Hydrol. Sci. J. 55(4), 555–564.  相似文献   

Multi-objective optimization for free-phase LNAPL recovery using evolutionary computation algorithms     

Zoi Dokou  George P. Karatzas 《水文科学杂志》2013,58(3):671-685

Abstract

A nonlinear, multi-objective optimization methodology is presented that seeks to maximize free product recovery of light non-aqueous phase liquids (LNAPLs) while minimizing operation cost, by introducing the novel concept of optimal alternating pumping and resting periods. This process allows more oil to flow towards the extraction wells, ensuring maximum free product removal at the end of the remediation period with minimum groundwater extraction. The methodology presented here combines FEHM (Finite Element Heat and Mass transfer code), a multiphase groundwater model that simulates LNAPL transport, with three evolutionary algorithms: the genetic algorithm (GA), the differential evolution (DE) algorithm and the particle swarm optimization (PSO) algorithm. The proposed optimal free-phase recovery strategy was tested using data from a field site, located near Athens, Greece. The PSO and DE solutions were very similar, while that provided by the GA was inferior, although the computation time was roughly the same for all algorithms. One of the most efficient algorithms (PSO) was chosen to approximate the optimal Pareto front, a method that provides multiple options to decision makers. When the optimal strategy is implemented, although a significant amount of LNAPL free product is captured, a spreading of the LNAPL plume occurs.

Editor Z.W. Kundzewicz; Associate editor L. See

Citation Dokou, Z. and Karatzas, G.P., 2013. Multi-objective optimization for free-phase LNAPL recovery using evolutionary computation algorithms. Hydrological Sciences Journal, 58 (3), 671–685.  相似文献   

Characterization of the Frequency of Extreme Earthquake Events by the Generalized Pareto Distribution     

V. F.?PisarenkoEmail author  D.?Sornette 《Pure and Applied Geophysics》2003,160(12):2343-2364

Recent results in extreme value theory suggest a new technique for statistical estimation of distribution tails (Embrechts et al., 1997), based on a limit theorem known as the Gnedenko-Pickands-Balkema-de Haan theorem. This theorem gives a natural limit law for peak-over-threshold values in the form of the Generalized Pareto Distribution (GPD), which is a family of distributions with two parameters. The GPD has been successfully applied in a number of statistical problems related to finance, insurance, hydrology, and other domains. Here, we apply the GPD approach to the well-known seismological problem of earthquake energy distribution described by the Gutenberg-Richter seismic moment-frequency law. We analyze shallow earthquakes (depth h<70 km) in the Harvard catalog over the period 1977–2000 in 12 seismic zones. The GPD is found to approximate the tails of the seismic moment distributions quite well over the lower threshold approximately M 10²⁴ dyne-cm, or somewhat above (i.e., moment-magnitudes larger than m _W =5.3). We confirm that the b-value is very different (b=2.06 ± 0.30) in mid-ocean ridges compared to other zones (b=1.00 ± 0.04) with a very high statistical confidence and propose a physical mechanism contrasting crack-type rupture with dislocation-type behavior. The GPD can as well be applied in many problems of seismic hazard assessment on a regional scale. However, in certain cases, deviations from the GPD at the very end of the tail may occur, in particular for large samples signaling a novel regime.  相似文献   

Sensitivity of goodness-of-fit statistics to rainfall data rounding off     

Roberto Deidda  Michelangelo Puliga 《Physics and Chemistry of the Earth》2006,31(18):1240-1251

An analysis based on the L-moments theory suggests of adopting the generalized Pareto distribution to interpret daily rainfall depths recorded by the rain-gauge network of the Hydrological Survey of the Sardinia Region. Nevertheless, a big problem, not yet completely resolved, arises in the estimation of a left-censoring threshold able to assure a good fitting of rainfall data with the generalized Pareto distribution. In order to detect an optimal threshold, keeping the largest possible number of data, we chose to apply a “failure-to-reject” method based on goodness-of-fit tests, as it was proposed by Choulakian and Stephens [Choulakian, V., Stephens, M.A., 2001. Goodness-of-fit tests for the generalized Pareto distribution. Technometrics 43, 478-484]. Unfortunately, the application of the test, using percentage points provided by Choulakian and Stephens (2001), did not succeed in detecting a useful threshold value in most analyzed time series. A deeper analysis revealed that these failures are mainly due to the presence of large quantities of rounding off values among sample data, affecting the distribution of goodness-of-fit statistics and leading to significant departures from percentage points expected for continuous random variables. A procedure based on Monte Carlo simulations is thus proposed to overcome these problems.  相似文献