共查询到20条相似文献,搜索用时 4 毫秒
1.
T. Tamiji E. Ameri 《International Journal of Environmental Science and Technology》2017,14(6):1235-1242
The effect of incorporation of alumina nanoparticles on the gas separation properties of the polysulfone–polyethylene glycol blend membranes containing 20% polyethylene glycol was examined. At first, a number of nanocomposite polysulfone–polyethylene glycol/alumina membranes were synthesized with alumina nanoparticles loaded into the polymer matrixes. The hybrid membranes were synthesized with six different alumina contents of 2.5, 5, 10, 15, 20, and 30 wt%. The polysulfone–polyethylene glycol and their hybrids inclusive alumina membranes were prepared via thermal phase-inversion method. The membranes were initially characterized using Fourier transform infrared spectroscopy, scanning electron microscope, and X-ray diffraction. Gas permeation properties of these membranes with different alumina contents were investigated for pure CO2, CH4, N2, and O2 gases. The results showed that not only these gases permeability but the CO2/N2, CO2/CH4, and O2/N2 ideal selectivity were improved with increasing alumina nanoparticle content of the membrane as well. Also the effect of feed pressure on the permeation properties of these membranes was investigated for pure CO2 gas. Finally, the results from the synthesized membranes were compared with Robeson’s upper bound line. 相似文献
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选择百慕大、白花三叶草、高羊茅三种土著植被和2%、3%、4%、5%4个不同坡度构建了缓冲带现场试验基地,开展面源污染防治试验。结果表明,滨岸缓冲带能有效截留径流水中的悬浮物质和降解渗流水中的氮、磷营养物质;植被和坡度的不同对缓冲带污染物净化效果影响显著,19 m长2%坡度缓冲带悬浮物截留率比5%坡度高14%,19 m长百慕大缓冲带悬浮物截留率比高羊茅高11%;进水浓度在10 mg/L以内时,2%坡度百慕大试验带渗流出水TN浓度低于《地表水环境质量标准》(GB3838-2002)Ⅴ类水标准;进水浓度在0.6 mg/L左右时,百慕大、白花三叶草、高羊茅和2%、3%、4%试验带渗流出水TP浓度均低于GB3838-2002Ⅲ类水标准;计算出缓冲带最佳宽度,2%坡度试验带比5%坡度试验带节约8.6 m,百慕大试验带比高羊茅试验带节约4.3 m。 相似文献
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M. John S. Heuss-Aßbichler A. Ullrich 《International Journal of Environmental Science and Technology》2016,13(9):2127-2134
In this study, a facile precipitation process to treat wastewater from zinc plating industry is presented. Water purification rates of Zn range between 96.40 % and 99.99 % depending on the reaction conditions. Optimal results are gained at a low pH value of 9, low temperature of 40 °C and a fast alkalization using NaOH solution containing 16 % pure NaOH. Traces of Ni, Fe, Zn, Cu and Cr present in the wastewater were almost completely removed. The precipitates were analysed by X-ray diffraction, infrared and Raman spectroscopy, electron microscopy and magnetic measurements. They consist of doped ZnO as a main phase. Although ZnO exclusively crystallizes in nanoparticle size, the morphology is directly influenced by the experimental parameters. Additionally, very small amounts of ZnCO3 and Zn(OH)2 were detected. Magnetic investigations indicate the incorporation of Ni and Fe into the ZnO lattice. The measured saturation magnetization is ~0.01 emu/g and the Curie temperature is ~75 °C. 相似文献
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A. S. Ertürk F. Göde A. E. Bozdoğan 《International Journal of Environmental Science and Technology》2017,14(11):2459-2470
A chemometric approach coupled with capillary electrophoresis based on the hierarchical cluster analysis and principal component analysis has been applied for the investigation of the water quality in the Golcuk-Isparta region (Lake District of Turkey). In the research area, Egirdir Lake, Golcuk Lake and surrounding ground and domestic waters have been utilized as drinking water resources. Golcuk Lake is distinctive in terms of high fluoride content (3.50 ± 0.21 mg/mL) which is endemic in volcanic areas where the water flow through volcanic rocks and sediments. Based on the analysis of major anions chloride, sulfate, nitrate and fluoride with capillary electrophoresis, twenty-four drinking water sampling sites in the research area were classified into four classes using the hierarchical cluster and principal component analysis. Combining the research area investigation results of hierarchical cluster and principal component analysis, it was found that fluoride concentration is the major diagnostic variable to determine the quality of drinking waters, and all the other anions are the important classification factors to predict the resources of the drinking water samples, individually. To sum up, this study reveals the potential of the use of capillary electrophoresis in combination with chemometric techniques for the determination of the quality and origin of drinking waters. 相似文献
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N.A. Gokcen 《Geochimica et cosmochimica acta》1979,43(4):637-641
It is shown mathematically that if the activity coefficient of water in ternary water-magma (aluminosilicate) systems is constant or varies only with the mole fraction of water, it is not necessary that the binary magmas form ideal solutions contrary to the claims by Burnham et al. (1978, Geochim. Cosmochim. Acta42, 275–276). A molecular viewpoint is presented to support this argument. The properties of analytical equations capable of representing the activity coefficients of usual and unusual systems are discussed. The correct form of the Gibbs-Dunhem equation for dissociative dissolution processes is presented to disprove the claims by Burnham (1975, Fortschr. Mineral.52, 101–118; 1975, Geochim. Cosmochim. Acta39, 1077–1084), and by Burnhamet al. (1978, Geochim. Cosmochim. Acta42, 275–276). 相似文献
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Jochen Schanze Johanna Trümper Cornelia Burmeister Dirk Pavlik Ivan Kruhlov 《Environmental Earth Sciences》2012,65(5):1405-1414
The paper presents a methodology on how to consistently deal with the future change and management options in integrated water
resources management (IWRM). It is based on a conceptual framework with a five step procedure for the formulation and analysis
of a so-called ‘parameterised regional futures’. Developing and testing the approach for IWRM is realised for the upper part
of the Western Bug River catchment (Ukraine). Special attention is paid to scenarios of change covering climate and land use.
The future regional climate is downscaled with the model CCLM. Land cover is projected after retrospective change detection
and the derivation of prospective algorithms. Parameters of the interrelations between land use and the water cycle are tackled
through using the concept of the model PWF-LU. The methodology is currently being tested to analyse the impacts of mid-term
regional change and management options on the water cycle of the catchment. 相似文献
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纳米金属微粒的采集观测及其对地球化学勘查的意义 总被引:1,自引:0,他引:1
近几年纳米地球化学的研究为成矿元素在覆盖层中的迁移机理研究提供了直接的微观证据,同时为将其应用于未来覆盖区找矿奠定了基础。通过详细介绍地气、土壤和矿石样品中纳米金属微粒的采集和观测方法,展示两个研究实例,并对不同介质中纳米金属颗粒的可对比性、对覆盖区隐伏矿勘查的意义进行讨论,认为地气和土壤中的纳米金属微粒可作为地球化学示踪物质。 相似文献
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In this paper, an enhanced backtracking search algorithm (so-called MBSA-LS) for parameter identification is proposed with two modifications: (a) modifying the mutation of original backtracking search algorithm (BSA) considering the contribution of current best individual for accelerating convergence speed and (b) novelly incorporating an efficient differential evolution (DE) as local search for improving the quality of population. The proposed MBSA-LS is first validated with better performance than the original BSA and some other typical state-of-the-art optimization algorithms on a benchmark of soil parameter identification in terms of effectiveness, efficiency, and robustness. Then, the efficiency of the MBSA-LS is further illustrated by two representative cases: identifying soil parameters from both laboratory tests and field measurements. All comparisons demonstrate that the proposed MBSA-LS algorithm can give accurate results in a short time. Finally, to conveniently solve the problems of parameter identification, a practical tool ErosOpt for parameter identification is developed by integrating the proposed MBSA-LS and some other efficient algorithms for readers to conduct the parameter identification using optimisation algorithms. 相似文献
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以膨润土为基材,添加沸石、黄铁矿制备高压实集成回填材料,采用渗析法和汽相法分别测得其在不同温度及自由、侧限条件下的土水特征曲线( SWCC),并采用SWCC模型对实验数据进行拟合.结果表明:低吸力范围内,施加相同的初始吸力,最终测得50℃试样含水率>20℃对应含水率,原因是温度影响渗析法所测吸力值及试样饱和后的微观结构;高吸力范围内,同一吸力值80℃对应的含水率最小,土水特征曲线斜率随温度升高而增大.应力状态对土水特征曲线的影响,在低吸力范围内显著,而高吸力范围内则影响不大.这与材料的微观结构有关.Van Genuehten模型对实测数据的拟合效果最佳. 相似文献
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A. Khanfekr K. Arzani Ph.D. A. Nemati Ph.D. M. Hosseini Ph.D. 《International Journal of Environmental Science and Technology》2009,6(1):105-112
(Lanthanum, Cerium)(Iron, Manganese, Cobalt, Palladium)(Oxygen)3-Perovskite catalyst was prepared by the citrate route and deposited on ceramic monoliths via dip coating procedure. The catalyst was applied on a car with XU7 motors and the amount of emission was monitored with vehicle emission test systems in Sapco company. The results were compared with the imported catalyst with noble metals such as palladium, platinum and rhodium by Iran Khodro company based on the Euro III standards. The catalysts were characterized by specific surface area measurements, scanning electron microscopy, X-ray diffraction, line scan and map. In the results, obtained in the home made sample, the amount of carbon monoxide, nitrogen oxides and hydrocarbons were lower than imported catalyst with Iran Khodro company with nobel metals. The illustration shows nano particles size on coat. The microstructure evaluation showed that the improved properties can be related to the existence of nano particles on coating. 相似文献
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实施找矿突破战略行动是保障我国经济社会可持续发展、提高矿产资源保障能力的重大举措,整装勘查是实现找矿突破的重要途径。整装勘查信息系统利用地理信息系统技术、数据库技术,整合全国、整装勘查区、重点工作区、实施项目等四层次的基础地理、地质、矿产地、矿业权、潜力评价成果等数据,实现数据管理、信息浏览、地图浏览、查询检索、统计分析、数据输出、地图制作及动态评估跟踪等功能,为全面了解掌握整装勘查区地质背景、找矿潜力及找矿进展,开展整装勘查业务支撑与研究、整装勘查区进展与成果展示提供了平台支持。通过整装勘查信息系统建设,笔者建议建设全国矿产勘查信息系统,集成基础地质、物化遥、潜力评价预测成果、矿业权等,及时跟踪补充重大进展地区的空间位置、地形地质图、重要勘探线剖面图、重要进展描述等矿产勘查数据,为国内矿产勘查的宏观决策、微观工作部署提供信息支持。 相似文献
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Geochemical data are typical compositional data which should be opened prior to univariate and multivariate data analysis. In this study, a frequency-based method (robust principal component analysis, RPCA) and a frequency-space-based method (spectrum–area fractal model, S–A) are applied to explore the effects of the data closure problem and to study the integrated geochemical anomalies associated with polymetallic Cu mineralization using a stream sediment geochemical dataset collected from the Zhongteng district, Fujian Province (China). The results show that: (1) geochemical data should be opened prior to RPCA to avoid spurious correlation between variables; (2) geochemical pattern is a superimposition of multi-processes and should be decomposed; and (3) the S–A fractal model is a powerful tool for decomposing the mixed geochemical pattern. 相似文献
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Turkey currently lacks a fully functional flood forecasting system (FFS). However, the studies necessary for establishing such a system are still being performed by the Turkish State Meteorological Service. The main purpose of this study was to determine the technical architecture of the FFS intended to be developed in Turkey and to design a flood forecasting and inundation-mapping system integrated with spatial data infrastructure (SDI). Because SDIs provide interoperability among the institutions by enabling collective use of data and services, this enables decision makers to take correct and rapid decisions regarding the forecasting. In the design of the system, the Web services architecture presented by the open geospatial consortium that develops international standards for SDI realizations was taken as a basis. Designed with flexibility and an expandable architecture, the system will enable instant access to up-to-date data from different institutions through Web services and meets the requirements of a real-time FFS. While the criteria requiring the expansion of the designed system were explained, its implementation was left for future studies. 相似文献
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P. Zhang T. Wan G. Zhang 《International Journal of Environmental Science and Technology》2012,9(2):287-296
Gravitational thickening is the prevailing method to reduce bio-sludge volume though the process is slow and usually requires addition of polyelectrolyte(s). This paper investigated the potential benefits of sonication on enhancing the bio-sludge gravitational thickening with very low energy dose, thereby called ??weak ultrasound??. Results showed that weak sonication significantly changed the bio-sludge settleability and the main mechanism was release of the loosely bound extracellular polymeric substances. The changes were strongly influenced by power density and sonication duration. Low frequency was better but the difference was insignificant. Weak sonication (<680?kJ/kg?DS) improved the sludge gravitational thickening while high ultrasonic energy deteriorated the process. Considering both the sludge thickening efficiency and energy consumption, the optimum conditions were 0.15?W/ml, 7?s and 25?kHz. Under such conditions, the energy dose was only 155?kJ/kg?DS, much lower than literature reports and the sludge settling time shortened from the original 24 to 12?h. Weak sonication could substitute expensive polyelectrolyte coagulant for bio-sludge thickening. Combination of weak sonication and polyelectrolyte could further reduce the settling time to 6?h. The final water content of the thickened bio-sludge was not changed after sonication or polyelectrolyte addition. 相似文献
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《Sedimentary Geology》2004,163(3-4):311-321
The velocity profile for unidirectional currents is usually determined by two forms of the law of the wall, which are valid for smooth and rough boundaries, respectively. The law of the wall for smooth boundaries outside the viscous sublayer and buffer layer applies where the boundary Reynolds number (Re*) is less than 5. The velocity in this case depends only on the dimensionless distance (yd) from the bottom. For rough boundaries where Re* is more than 65, the law of the wall is independent of the boundary Reynolds number, but the bottom roughness (k) has to be taken into account. The mean or median particle grain size (D) is commonly substituted for bottom roughness. At present, there is no generally accepted law of the wall for the transitional flow regime between hydrodynamically smooth and rough conditions. In this paper, an integrated law of the wall is proposed for the transitional regime, yielding velocity profiles that correspond well to observed velocity profiles under these conditions. The result is applied to a set of flume data, using an improved procedure to determine the bedload transport rate. 相似文献
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P. N. Mahajan 《Journal of Earth System Science》2001,110(3):225-229
Recent algorithms for Special Sensor Microwave/Imager (DMSP-SSM/I) satellite data are used for estimating integrated water
vapour over the Indian seas. Integrated water vapour obtained from these algorithms is compared with that derived from radiosonde
observations at Minicoy and Port Blair islands. Algorithm-3 of Schlussel and Emery (1990) performed best. On the basis of
this algorithm, distribution of integrated water vapour is determined during the monsoon depression (22nd–27th July, 1992)
that formed over the Bay of Bengal. 相似文献