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Properties study and phylogenetic analysis of a bacterial strain with high de-emulsification efficiency

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Journal of Harbin institute of Technology(New Series) 2009年第3期16卷 350-354页

作者：侯宁杨基先马放李大鹏温沁雪徐暘郭静波 State Key Laboratory of Urban water resources and Environment Harbin Institute of Technology School of Municipal and environmental engineering Harbin Institute of Technology

For further practical application, the phylogenetic analysis and de-emulsification properties study of strain XH1 with high de-emulsification efficiency isolated from crude oil contaminated soil in Daqing oil field were conducted with a surfactant-stabilized water-kerosene model emulsion. The factors influencing the de-emulsification efficiency and the generation site of de-emulsification active component of the strain were also investigated. The similarity of 16SrDNA sequences between strain XH1 and Bacillus mojavensis （DQ993678）was 99%. According to the physiological biochemical test, strain XH1 was preliminarily identified as Bacillus mojavensis. The logarithmic growth, stable phase and decline phase of strain XHI were determined as 14, 18 and 28 h, respectively. The best de-emulsification activity emerged after cultivating for 18h, and the complete de-emulsification was achieved at 24 h. The most favorable incubation conditions for de-emulsification occurred with pH of 6. 0 at 30 ℃. The de-emulsification capability of strain XH1 was mainly resulted from extracellular metabolites. The above results indicate that strain XH1 has high de-emulsification efficiency and is potential as a commercial de-emulsifier.

关键词： efficient bio-demulsification phylogenetic analysis demulsifying performance active site

Monitoring models for base flow effect and daily variation of dam seepage elements considering time lag effect

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water Science and engineering 2018年第4期11卷 344-354页

作者： Shao-wei Wang Ying-li Xu Chong-shi Gu Teng-fei Bao School of environmental and Safety engineering Changzhou University State Key Laboratory of Hydrology-water resources and Hydraulic engineering Hohai University

Affected by external environmental factors and evolution of dam performance, dam seepage behavior shows nonlinear time-varying characteristics. In this study, to predict and evaluate the long-term development trend and short-term fluctuation of the dam seepage behavior, two monitoring models were developed, one for the base flow effect and one for daily variation of dam seepage elements. In the first model, to avoid the influence of the time lag effect on the evaluation of seepage variation with the time effect component of seepage elements, the base values of the seepage element and the reservoir water level were extracted using the wavelet multi-resolution analysis method, and the time effect component was separated by the established base flow effect monitoring model. For the development of the daily variation monitoring model for dam seepage elements, all the previous factors, of which the measured time series prior to the dam seepage element monitoring time may have certain influence on the monitored results, were considered. Those factors that were positively correlated with the analyzed seepage element were initially considered to be the support vector machine(SVM) model input factors, and then the SVM kernel function-based sensitivity analysis was performed to optimize the input factor set and establish the optimized daily variation SVM model. The efficiency and rationality of the two models were verified by case studies of the water level of two piezometric tubes buried under the slope of a concrete gravity *** analysis of the optimized SVM model shows that the influences of the daily variation of the upstream reservoir water level and rainfall on the daily variation of piezometric tube water level are processes subject to normal distribution.

关键词： Dam seepage monitoring model Time lag effect Support vector machine(SVM) Sensitivity analysis Base flow Daily variation Piezometric tube water level

Effect of freeze-thaw cycles on mechanical behavior of clay-gravel mixtures

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Journal of Mountain Science 2022年第12期19卷 3615-3626页

作者： ZHANG Yong-gan LIU Si-hong DENG Gang FANG Bin-xin ZHANG Yan-yi LU Yang College of water Conservancy and Hydropower engineering Hohai UniversityNanjing 210098China Key Laboratory of Construction and Safety of water engineering of the Ministry of water resources China Institute of Water Resources and Hydropower ResearchBeijing 100048China

The use of clay-gravel mixtures(i.e.,adding excavated or natural gravel particles into clay soil matrix)as the main filling materials is increasing in the anti-seepage system of high Earth Core Rockfill Dams(ECRDs).With the continuous construction of high ECRDs in the Chinese plateaus and cold regions,it is of great urgency and importance to understand the physical and mechanical characteristics of compacted clay-gravel mixtures under freeze-thaw *** this end,laboratory freezing-thawing tests,computed tomography(CT),and triaxial compression tests were conducted to evaluate the effects of freezethaw cycles on moisture loss,pore structure characteristics,stress-strain behavior,failure strength,elastic modulus,cohesion,and internal friction angle of compacted clay-gravel *** results demonstrate that,1)the freeze-thaw cycle significantly changed the mechanical characteristics of the clay-gravel mixture samples,but the shape of the stress-strain curve is less sensitive to it.2)The failure strength of samples exhibits a significant decrease after the first freeze-thaw cycle,but shows a certain increase as the number of freeze-thaw cycles increases from 1 to 2.3)The elastic modulus of samples first decreases and then increases with increasing freeze-thaw cycle,and the most severe deterioration was observed after the first freeze-thaw cycle.4)Regardless of the number of freeze-thaw cycles,there is a linear relationship between failure strength and elastic modulus for a sample that has suffered freeze-thaw weathering.5)The cohesion of samples decreases firstly and then slightly increases with increasing freeze-thaw cycles,while the internal friction angle is hardly affected.

关键词： Earth core rockfill dam Clay-gravel mixtures Freeze-thaw cycles Computed tomography Mechanical behavior

Rare earth element geochemistry of Cambrian phosphorites from the Yangtze Region

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Journal of Rare Earths 2013年第1期31卷 101-112页

作者：陈吉艳杨瑞东魏怀瑞高军波 College of resources and environmental engineering Guizhou University

Analysis on P205 and REE （rare earth elements） in basal Cambrian phosphorites from the Yangtze Region, showed that the phosphorites from Bailongtan in Yunnan Province, Zhijin, Jinsha, Xishui, Zunyi, Tianzhu and Tongren in Guizhou Province, Shan- grao in Jiangxi Province, Jiangshan in Zhejiang Province and Nanjing in Jiangsu Province contained high REE contents in phos- phorites, especially those from Tianzhu and Tongren in Guizhou Province, Shangrao in Jiangxi Province, Jiangshan in Zhejiang Province and Nanjing in Jiangsu Province. Among them, the highest REE contents reached up to 1361.59×10^-6 and P205 contents up to 29.45%. In contrast, phosphorites from Kaiyang, Qingzhen and Zhenyuan in Guizhou Province had relatively low total REE con- tents and low P205 contents, with the lowest total REE content of 53.19× 10^-6, and the lowest P205 content of 0.07%. REE contents exhibited a positive correlation with phosphorous contents, indicating a close genetic relationship between REE and phosphorous ele- ment. The main reason was the difference of the sedimentary environments and the contents of phosphorous and REE in deep water mass formed in upwelling currents, at an upper slope facies （Slu） in reducing condition due to relatively closed sedimentary environ- ment. It was very difficult for the upswelling phosphorous and REE to deposit, massive phosphorous deposits were hard to be formed. At a deep water ramp facies （DRa） in the ascending process of currents, phosphorus and REE underwent differentiation rather than sedimentation. Consequently, the contents of P205 sediments and REE were low. At a shallow water ramp facies （including shoals and tidal flats）（SRa）, with active seawater circulation and phosphatic supplement, sunny weather, high nutrition and rapid growth of algae, were benefitial for the physical enrichment of carbonate sediments. Therefore, massive phosphorite deposits were easy to be tbrmed with abundant REE minerals, and finally turned into high REE be

关键词： rare earth elements (REE) phosphorite basal Cambrian Yangtze Region

Application of Hausdorff fractal derivative to the determination of the vertical sediment concentration distribution

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International Journal of Sediment Research 2023年第1期38卷 12-23页

作者： Hongguang Sun Shiqian Nie Aaron I.Packman Yong Zhang Dong Chen Chengpeng Lu Chunmiao Zheng State Key Laboratory of Hydrology-water resources and Hydraulic engineering Hohai University College of Mechanics and Materials Hohai University College of Mathematics and systems Science Shandong University of Science and Technology Department of Civil and environmental engineering Northwestern University Department of Geological Sciences University of Alabama institute of Geographic Sciences and Natural resources Research Chinese Academy of Sciences College of Hydrology and water resources Hohai University School of environmental Science and engineering Southern University of Science and Technology

The Rouse formula and its variants have been widely used to calculate the steady-state vertical concentration distribution for suspended sediment in steady sediment-laden flows, where the diffusive flux is assumed to be Fickian. Turbulent flow, however, exhibits fractal properties, leading to non-Fickian diffusive flux for sediment particles. To characterize non-Fickian dynamics of suspended sediment, the current study proposes a Hausdorff fractal derivative based advection-dispersion equation(HADE)model, where the Fickian diffusive flux in the Rouse model is replaced by a fractal derivative re-scaled using a constant diffusivity. The order of the Hausdorff fractal derivative is designed to characterize the influence of the multi-fractal turbulence structure on sediment diffusion. Applications show that the HADE model, with the analytical solution expressed using a stretched exponential function, can accurately describe the observed vertical concentration profiles for suspended sediment with different *** improvement well captures the non-exponential decay of the vertical sediment concentration in turbulent flow. Further analyses of measured sediment concentration profiles reveal that the Hausdorff fractal order decreases with the Rouse parameter, which describes the stronger impact of turbulent flow and a more uniform sediment concentration profile for smaller particles. Model comparisons also show that the HADE model provides better performance in describing the sediment concentration profiles than the improved Rouse formula and the standard fractional derivative advection-dispersion equation(FADE), which either under-or over-estimates vertical displacement of sediment particles, likely due to coherent turbulent structures.

关键词： Anomalous diffusion Hausdorff fractal derivative Vertical concentration distribution Suspended sediment Metric transform

Analysis on REE geochemical characteristics of three types of REE-rich soil in Guizhou Province,China

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Journal of Rare Earths 2010年第S1期28卷 517-522页

作者：陈吉艳杨瑞东 College of resources and environmental engineering Guizhou University

The three kinds of soil formed by the weathering of the basalt in Yema village,Weining county of Guizhou province,the carbonate rock in Guiyang district and the phosphorite in the REE-bearing phosphate mining area in Zhijin county of Guizhou province were all rich in *** contents of LREE in these three soil were higher than that of HREE,which was caused by the different properties of LREE and HREE *** light REE could be easily absorbed by kaolinite grains,LREE was fully enriched in the process of desorption,migration and re-absorption,which formed a typical LREE *** chondrite normalized distribution models of those three types of REE-enriched soil are basically similar,which belong to the right deviation type,namely,rich in light rare earth element but short of heavy rare earth element,and showing Ce negative *** showed intense negative anomalies in the REE in the soil formed by the weathering of the sedimentary parent rocks(such as carbonate rock and phosphorite),while no pronounced Eu anomaly was found in the REE in the soil formed by the weathering of volcanic rocks(such as basalt).It is clear that though there were intense migration and enrichment of REE during the weathering process of rocks,no obvious differentiation of REE occurred and some features of the parent rocks were *** is why REE is of value in analyzing the source of materials.

关键词： soil REE (rare earth elements) Guizhou province

Verification of A Numerical Harbour Wave Model

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China Ocean engineering 2007年第4期21卷 647-658页

作者：潘军宁洪广文左其华王登婷 State Key Laboratory of Hydrology-water resources and Hydraulic engineering Hohai University State Key Laboratory of Hydrology-water resources and Hydraulic engineering Nanjing Hydraulic Research Institute

A numerical model for wave propagation in a harbour is verified by use of physical models. The extended time-dependent mild slope equation is employed as the governing equation, and the model is solved by use of ADI method containing the relaxation factor. Firstly, the reflection coefficient of waves in front of rubble-mound breakwaters under oblique incident waves is determined through physical model tests, and it is regarded as the basis for simulating partial reflection boundaries of the numerical model. Then model tests on refraction, diffraction and reflection of waves in a harbour are performed to measure wave height distribution. Comparative results between physical and numerical model tests show that the present numerical model can satisfactorily simulate the propagation of regular and irregular waves in a harbour with complex topography and boundary conditions.

关键词： wave mild slope equation numerical model harbour verification

Trend and Dynamic Cause of Sediment Particle Size on the Adjacent Continental Shelf of the Yangtze Estuary

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China Ocean engineering 2016年第6期30卷 992-1003页

作者：杨云平张明进李义天樊咏阳 Key Laboratory of engineering Sediment Tianjin Research Institute for Water Transport EngineeringMinistry of Transport State Key Laboratory of water resources & Hydropower engineering Science Wuhan University

Based on the measured data in recent 20 years, the variation trends of the median grain size of the surface sediment, the sand-silt boundary and the mud area on the adjacent continental shelf of the Yangtze Estuary were analyzed in depth, and the effects of natural mechanism and human activities were discussed. The results show that：（1） In recent years （2006-2013）, the median grain size of sediment and the distribution pattern of grouped sediments in the adjacent continental shelf area to the Yangtze Estuary have presented no obvious change compared with those before 2006; （2） The median diameter of the surface sediment in the continental shelf area displayed a coarsening trend with the decrease of sediment discharge from the basin and the drop in suspended sediment concentration in the shore area; （3） In 2004-2007, the sand-silt boundary in the north part （31 ~30＇N） of the continental shelf area presented no significant changes, while that in the south part （31~30＇S） moved inwards; In 2008-2013, both the sand-silt boundaries in the north and south parts of the continental shelf area moved inwards, mainly due to the fact that in the dry season, a relatively enhanced hydrodynamic force of the tides was generated in the Yangtze River, as well as a decreased suspended sediment concentration and a flow along the banks in North Jiangsu; （4） The mud area where the maximum deposition rate is found in the Yangtze Estuary, tends to shrink due to the drop in sediment discharge from the basin, and the decrease in suspended sediment concentration in the shore area and erosion in the delta. Moreover, it tended to shift to the south at the same time because the implement of the training works on the deep-water channel of the North Passage changed the split ratio between the North and South Passages with an increase in the power of the discharged runoff in the South Passage.

关键词： surface sediment sand-silt boundary mud area trend and cause adjacent continental shelf, YangtzeEstuary

Dynamic Characteristics of Positive Pulsed Dielectric Barrier Discharge for Ozone Generation in Air

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Plasma Science and Technology 2016年第2期18卷 147-156页

作者：魏林生彭邦发李鸣章亚芳胡兆吉 School of resources Environmental & Chemical EngineeringNanchang University Department of Mechanical and Aerospace engineering Florida Institute of Technology

A comprehensive dynamic model consisting of 66 reactions and 24 species is developed to investigate the dynamic characteristics of ozone generation by positive pulsed dielectric barrier discharge（DBD） using parallel-plate reactor in *** electron energy conservation equation is coupled to the electron continuity equation,the heavy species continuity equation,and Poisson＇s equation for a better *** reliability of the model is experimentally *** model can be used to predict the temporal and spatial evolution of species,as well as streamer *** simulation results show that electron density increases nearly exponentially in the direction to the anode at the electron *** propagation velocity is about 5.26×104m/s from anode to cathode in the simulated *** primary positive ion,negative ion,and excited species are O_2~＋,O_3^-and O_2（1？g） in pulsed DBD in air,respectively.N_2 O has the largest density among nitrogen oxides.e and N_2~＋densities in the streamer head increase gradually to maximum values with the development of the ***,the O_2~＋,O,O_3,N_2（A^3Σ） and N_2 O densities reach maximum values in the vicinity of the anode.

关键词： dynamics pulsed DBD parallel-plate reactor ozone air