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822.
Mingxing Yu 《International Journal of Green Energy》2020,17(5):332-348
ABSTRACTWind speed forecasting plays an important role in power grid dispatching management. This article proposes a short-term wind speed forecasting method based on random forest model combining ensemble empirical modal decomposition and improved harmony search algorithm. First, the initial wind speed data set is decomposed into several ensemble empirical mode functions by EEMD, then feature extraction of each sub-modal IMF is performed using fast Fourier transform to solve the cycle of each sub-modal IMF. Next, combining the high-performance parameter optimization ability of the improved harmony search algorithm, two optimal parameters of random forest model, number of decision trees, and number of split features are determined. Finally, the random forest model is used to forecast the processing results of each submodal IMF. The proposed model is applied to the simulation analysis of historical wind data of Chaoyang District, Liaoning Province from April 27, 2015 to May 22, 2015. To illustrate the suitability and superiority of the EEMD-RF-IHS model, three types of models are used for comparison: single models including ANN, SVM, RF; EMD combination models including EMD-ANN, EMD-SVM, EMD-RF; EEMD combination models including EEMD-ANN, EEMD-SVM, EEMD-RF. The analysis results of evaluation indicators show that the proposed model can effectively forecast short-term wind data with high stability and precision, providing a reference for forecasting application in other industry fields. 相似文献
823.
Vasil'eva I. A. Vasil'ev A. G. Lyubashevskii N. M. Chibiryak M. V. Zakharova E. Yu. Tarasov O. V. 《Russian Journal of Ecology》2003,34(6):405-412
Monitoring of A. uralensis populations in Kamenskii raion, Sverdlovsk oblast, in 1992–2002 and in Kaslinskii raion, Chelyabinsk oblast, in 2000–2001 revealed an increase in the proportion and diversity of minor morphogenetic aberrations and abnormalities in the structure of the cranium along the axis of the Eastern Ural Radioactive Trace (EURT). The samples from the southern and northern parts of the EURT (contaminated with 90Sr to 500 and 4 Ci/km2, respectively) were characterized by directed deviations from the control with respect to the frequencies of phenes of nonmetric cranial traits and an increase in the level of their fluctuating asymmetry in young females, which is indicative of epigenetic rearrangements in populations living in a radioactive environment. 相似文献
824.
石油化工企业事故应急救援预案现状及改进建议 总被引:7,自引:3,他引:4
石油化工行业是一个高危行业 ,具有易燃易爆、高温高压、有毒有害的特点 ,发生事故的概率高 ,且后果严重。制定事故应急救援预案是风险控制措施的一个重要组成部分 ,可以有效地防止事故的扩大 ,减轻事故造成的财产和生命损失。笔者主要探讨应急救援管理层面上的问题 ;阐述了我国政府和有关部门在应急救援管理方面的有关规定 ,石化行业的应急救援体系 ;指出了目前事故应急救援预案存在的不完善、不规范 ,应急装备不完备和缺乏社会救援联动机制等问题 ;建议企业和政府联合制定应急预案 :形成企业、地方政府和国家三方事故应急救援联动机制 ,实现统一指挥 ,资源共享 ,协调作战 ,发挥整体应急救援能力。 相似文献
825.
Feed-forward dose control of wastewater chlorination using on-line pH and ORP titration 总被引:1,自引:0,他引:1
Yu RF 《Chemosphere》2004,56(10):973-980
In this study, a simple automatic pH-ORP titration device was developed for identifying the various ammonia concentrations and chlorine dose requirements for wastewater chlorination by identifying the peaks in the ORP-slope profiles and knees/valleys in the pH profiles. In addition, breakpoint chlorination experiments have shown that the ORP values at the monochloramine humps and breakpoints are linearly correlated with the ammonia concentrations. Therefore, a feed-forward control strategy, based on the chlorine/ammonia weight ratio (Cl/N), is proposed in this paper, to control the chlorine doses for a continuous wastewater chlorination experiment in a laboratory-scale reactor. The result of this continuous wastewater chlorination experiment has shown that the pH-ORP titration was able to precisely determine the variations of ammonia concentrations in the chlorination influent. Under this control strategy, effective and stable disinfection efficiencies in terms of total coliform count were obtained. 相似文献
826.
Bronchial dosimeters have been designed for adult Chinese males and females for home and mine exposures, which can give the bronchial doses from radon progeny by direct measurements. The bronchial dosimeter for home exposures consists of five 400-mesh wire screens. With a sampling face velocity of 3.3 cm s(-1) for Chinese males and 2.7 cm s(-1) for Chinese females, the deposition pattern on the wire screens were found to satisfactorily match the variation of the dose conversion coefficients (in units of mSv WLM(-1)) with the size of radon progeny from 1 to 1000 nm. The bronchial dosimeter for mine exposures consists of four 250-mesh wire screens. With a sampling face velocity of 3.3 cm s(-1), the deposition pattern on the wire screens were found to satisfactorily match the variation of the dose conversion coefficients for both Chinese males and females. In this way, the bronchial dosimeters directly give the bronchial doses from the alpha counts recorded on the wire-screens. 相似文献
827.
In this study, cabbage [Brassica rapa L. subsp. chinensis (L.) Hanelt cv. Xinza No 1], mung bean [Vigna radiata (L.) R. Wilczek var. radiata cv. VC-3762], and wheat (Triticum aestivum L. cv. Altas 66) were grown in Pb-contaminated soils. Application of ethylenediaminetetraacetic acid (EDTA) (3.0 mmol of EDTA/kg soil) to the soil significantly increased the concentrations of Pb in the shoots and roots of all the plants. Lead concentrations in the cabbage shoots reached 5010 and 4620 mg/kg dry matter on Days 7 and 14 after EDTA application, respectively. EDTA was the best in solubilizing soil-bound Pb and enhancing Pb accumulation in the cabbage shoots among various chelates (EDTA, diethylenetriaminepentaacetic acid [DTPA], hydroxyethylenediaminetriacetic acid [HEDTA], nitrilotriacetic acid [NTA], and citric acid). Results of the sequential chemical extraction of soil samples showed that the Pb concentrations in the carbonate-specifically adsorbed and Fe-Mn oxide phases were significantly decreased after EDTA treatment. The results indicated that EDTA solubilized Pb mainly from these two phases in the soil. The relative efficiency of EDTA enhancing Pb accumulation in shoots (defined as the ratio of shoot Pb concentration to EDTA concentration applied) was highest when 1.5 or 3.0 mmol EDTA/kg soil was used. Application of EDTA in three separate doses was most effective in enhancing the accumulation of Pb in cabbage shoots and decreased mobility of Pb in soil compared with one- and two-dose application methods. This approach could help to minimize the amount of chelate applied in the field and to reduce the potential risk of soluble Pb movement into ground water. 相似文献
828.
The underlying mechanisms of interaction between the symbiotic nitrogen-fixation process and main physiological processes, such as assimilation, nutrient allocation, and structural growth, as well as effects of nitrogen fixation on plant responses to global change, are important and still open to more investigation. Appropriate models have not been adequately developed. A dynamic ecophysiological model was developed in this study for a legume plant [Glycine max (L.) Merr.] growing in northern China. The model synthesized symbiotic nitrogen fixation and the main physiological processes under variable atmospheric CO2 concentration and climatic conditions, and emphasized the interactive effects of these processes on seasonal biomass dynamics of the plant. Experimental measurements of ecophysiological quantities obtained in a CO2 enrichment experiment on soybean plants, were used to parameterize and validate the model. The results indicated that the model simulated the experiments with reasonable accuracy. The R2 values between simulations and observations are 0.94, 0.95, and 0.86 for total biomass, green biomass, and nodule biomass, respectively. The simulations for various combinations of atmospheric CO2 concentration, precipitation, and temperature, with or without nitrogen fixation, showed that increasing atmospheric CO2 concentration, precipitation, and efficiency of nitrogen fixation all have positive effects on biomass accumulation. On the other hand, an increased temperature induced lower rates of biomass accumulation under semi-arid conditions. In general, factors with positive effects on plant growth tended to promote each other in the simulation range, except the relationship between CO2 concentration and climatic factors. Because of the enhanced water use efficiency with a higher CO2 concentration, more significant effects of CO2 concentration were associated with a worse (dryer and warmer in this study) climate. 相似文献
829.
Cadmium(II) removal from aqueous solutions by pre-treated biomass of marine alga Padina sp 总被引:1,自引:0,他引:1
In this study, the adsorption properties of a pre-treated biomass from marine alga Padina sp., a biomass collected from Surin Island, Thailand, for removal of cadmium(II) ions from aqueous solutions was investigated. Batch and column experiments were conducted to determine the adsorption properties of the modified biomass. At a pH of 5, the maximum removal capacity of the biomass is 0.53 mmol/g. The kinetics of cadmium(II) adsorption were fast with 90% of adsorption taking place within 35 min. This study demonstrated that the pre-treated biomass of Padina sp. could be used as an efficient biosorbent for the treatment of cadmium(II)-bearing wastewater streams. 相似文献
830.
Analysis of microcystins in cyanobacteria blooms and surface water samples from Meiliang Bay,Taihu Lake,China 总被引:18,自引:0,他引:18
Shen PP Shi Q Hua ZC Kong FX Wang ZG Zhuang SX Chen DC 《Environment international》2003,29(5):641-647
Taihu Lake is the third largest freshwater lake in China. In recent years, the water pollution of cyanobacteria blooms has become a severe problem in this area. Microcystins (MCs) are an important group of toxic compounds mainly produced by some cyanobacteria species and have both acute and chronic hepatotoxic effects on animals and humans. This paper presents the first data on the identification and detection of MCs in both natural occurring cyanobacteria blooms and surface water samples (0-0.5 m), collected from Meiliang Bay, Taihu Lake, China. A conventional method for extraction and isolation of MCs from cyanobacteria blooms was applied. High-performance liquid chromatography (HPLC) analysis showed that the main toxic component in the cyanobacteria materials was MC-LR. The monoclonal antibody (mAb) against MC-LR produced by hybridoma technique was employed for direct competitive ELISA to detect the concentrations of MCs in bloom and water samples collected in 2001. The results not only revealed the presence of MCs but also temporal variations of MCs levels of three sampling stations in Meiliang Bay in 1 year. It is obvious that the MC contents were relatively higher during warm months and related with the status of eutrophication. Our study indicates the threat associated with MCs in water body of Taihu Lake. To prevent the MCs potential hazard on public health in this area, some necessary measures of monitoring and control of growth of cyanobacteria are urgently needed. 相似文献