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Assessment of Groundwater Physico-Chemical Quality in the Ouémé Delta (Southern-Benin)

Journal of Environmental Protection 2024年第3期15卷 298-317页

作者： Aoulatou Alassane Zakari Dadja Toyou Masamaéya Gnazou Abdoukarim Alassane Kodjo Apelete Raoul Kpegli Ousmane Touré Boukari Bio Guidah Chabi Bénito Didier Koukpohounsi Daouda Mama Laboratory of Applied Hydrology National Water Institute University of Abomey-Calavi Benin (LHA/INE/UAC) Cotonou B&eacutenin International Chair in Mathematical Physics and Applications (ICMPA—UNESCO Chair) Cotonou B&eacutenin Laboratory of Applied Hydrology and Environment Faculty of Sciences University of Lom&eacute Togo (LHAE/FDS/UL) Lom&eacute Togo

Groundwater resources are the main sources of water used to supply drinking water to the population of the Ouémé Delta via the Continental Terminal aquifer. Urbanization, population growth, and agricultural and industrial activities have resulted in a deterioration in the quality of these resources. To assess the quality of the delta’s groundwater and its suitability for human consumption and irrigation, a total of fourteen (14) physico-chemical parameters were analyzed in some forty existing water points between September 2020 and March 2021, using standard water analysis techniques. The values obtained were compared with the potability standards recommended by the World Health Organization (WHO) and the Republic of Benin and were subjected to statistical analysis (principal component analysis (PCA)). In addition, methods for determining the suitability of water for irrigation were used. The results showed that the waters are acidic to slightly neutral and influenced by ambient temperature. In addition, the waters are moderately mineralized, with conductivities (24 - 1205 μS/cm) in line with WHO standards. A comparison of the analytical results of the WHO (2017) and Benin (2001) standards indicates that the majority of the waters studied are of good quality for all the chemical parameters considered. Nevertheless, some samples show levels of nitrates (21%), potassium (14% to 16%), calcium (13%), ammonium (12%), nitrites (8%) and bicarbonates (10%) over their respective standards. The Wilcox and Riverside diagrams indicate that the majority of waters (90%) have excellent suitability for irrigation and no negative effect on soil fertilization.

关键词： Benin OuéméDelta Groundwater Physico-Chemical Quality Consumption Irrigation

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Advances on numerical and experimental investigation of ship roll damping

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水动力学研究与进展B辑:英文版 2023年第3期35卷 431-448页

作者： Patrick Sumislawski Moustafa Abdel-Maksoud Institute for Fluid Dynamics and Ship Theory Hamburg University of Technology (TUHH) Hamburg Germany

This paper presents recent developments towards efficient and reliable methods for roll damping estimation based on numerical simulations as well as model tests using the harmonic excited roll motion(HERM)technique.A newly designed automatic roll damping estimation procedure shows the advantage of a just-in-time post processing of experimental measurement ***-time analysis of the measured roll damping values permits a considerable shortening of the test ***,a large number of investigations can be carried out with relatively manageable effort in order to determine the roll damping behavior of different keel configurations or at operating conditions,e.g.,different sized keels or Froude *** addition,HERM measurement method is applied to investigate the memory *** this purpose,different excitation schemes are introduced and the results are ***,a study of the scale effect on the roll damping properties is conducted,in which experimental and numerical investigations are performed for two scales of a ship ***,a method is developed that significantly reduces the effort of Reynolds average Navier-Stokes(RANS)-based simulations of roll *** reduction of simulation time is achieved by introducing an artificial *** obtained results show that the developed method is very well applicable for numerical as well as in experimental *** the model tests using HERM technique,the model is free and the rudder is used to keep the straight-ahead *** analysis of the numerical and experimental results shows that the influence of the rudder induced force and moment during HERM tests is not negligible and the contribution of the rudder must be taken into account by estimating the roll ***,a new concept is developed to investigate the parametric roll behavior of ships,which allows neglecting the consideration of the complex modelling of free surface waves in the *** the RAN

关键词： Roll damping harmonic excited roll motion rudder HERM experimental fluid dynamics(EFD) CFD

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Fore-Body Side Vortex of KVLCC2 at 30°Drift: A Trailing Vortex Resolved with DES and Compared to PIV Data

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Open Journal of Fluid Dynamics 2019年第4期9卷 303-325页

作者： Dag-Frederik Feder Ivan Shevchuk Ahmed Sahab Lukas Gerwers Moustafa Abdel-Maksoud fds/tuhh Hamburg Germany

A hybrid RANS-LES approach is used to resolve the Fore-body Side Vortex (FSV) separating from the KVLCC2 hull at 30° drift angle and Reynolds number ReLoa ≈ 2.56e6. The performance of the DES approach is evaluated using a proper grid study. Besides, the following aspects of the CFD results are investigated: the resolution of turbulent energy, the prediction of instantaneous and time-averaged vortical structures, local flow features, the limiting streamlines and the evolution of the vortex core flow. New PIV data from wind tunnel experiments is compared to the latter. The results form a basis for future investigations in particular on the vortex interaction further downstream and the applicability of different kinds of turbulence models to trailing vortices like the FSV. Turbulence modelling is realised with the k-ω-SST-IDDES model presented in [1], the grids’ cell count is 6.4 M, 10.5 M and 17.5 M. Grid convergence of the time-averaged vortex core flow is observed. OpenFOAM version 1806 is used to carry out the simulations and snappyHexMesh to build the mesh.

关键词： KVLCC2 DES Hybrid RANS-LES PIV Trailing Vortex Drift

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Slice Thickness Optimization for the Focused Ion Beam-Scanning Electron Microscopy 3D Tomography of Hierarchical Nanoporous Gold

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Nanomanufacturing and Metrology 2022年第2期5卷 112-118页

作者： Alexander Shkurmanov Tobias Krekeler Martin Ritter Electron Microscopy Unit Hamburg University of Technology(TUHH)Eißendorfer Straße 4221073HamburgGermany

The combination of focused ion beam (FIB) with scanning electron microscopy (SEM), also known as FIB-SEM tomography, has become a powerful 3D imaging technique at the nanometer scale. This method uses an ion beam to mill away a thin slice of material, which is then block-face imaged using an electron beam. With consecutive slicing along the z-axis and subsequent imaging, a volume of interest can be reconstructed from the images and further analyzed. Hierarchical nanoporous gold (HNPG) exhibits unique structural properties and has a ligament size of 15–110 nm and pore size of 5–20 nm. Accurate reconstruction of its image is crucial in determining its mechanical and other properties. Slice thickness is one of the most critical and uncertain parameters in FIB-SEM tomography. For HNPG, the slice thickness should be at least half as thin as the pore size and, in our approach, should not exceed 10 nm. Variations in slice thickness are caused by various microscope and sample parameters, e.g., converged ion milling beam shape, charging effects, beam drift, or sample surface roughness. Determining and optimizing the actual slice thickness variation appear challenging. In this work, we examine the influence of ion beam scan resolution and the dwell time on the mean and standard deviation of slice thickness. After optimizing the resolution and dwell time to achieve the target slice thickness and lowest possible standard deviation, we apply these parameters to analyze an actual HNPG sample. Our approach can determine the thickness of each slice along the z-axis and estimate the deviation of the milling process along the y-axis (slow imaging axis). For this function, we create a multi-ruler structure integrated with the HNPG sample.

关键词： Focused ion beam Scanning electron microscopy Tomography Hierarchical nanoporous gold

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Generalized Trigonometric Power Sums Covering the Full Circle

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Journal of Applied Mathematics and Physics 2022年第2期10卷 405-414页

作者： Hans Jelitto Institute of Advanced Ceramics Hamburg University of Technology (TUHH) Hamburg Germany

The analytical calculation of the area moments of inertia used for special mechanical tests in materials science and further generalizations for moments of different orders and broader symmetry properties has led to a new type of trigonometric power sums. The corresponding generalized equations are presented, proven, and their characteristics discussed. Although the power sums have a basic form, their results have quite different properties, dependent on the values of the free parameters used. From these equations, a large variety of power reduction formulas can be derived. This is shown by some examples.

关键词： Trigonometric Power Sum Power Reduction Formula Trigonometric Identity Central Binomial Coefficient

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Experimental Study of Inducing Compressive Stress by Anti-welding Heating Treatment in a Thin Plate Weldment with Variant Temperatures

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Journal of Materials Science & Technology 2002年第2期18卷 151-154页

作者： HuainingCHEN W.Fricke 等 InstituteofMetalResearch ChineseAcademyofSciencesShenyang110016China DepartmentofShipstructuresandStructuralAnalysis TUHH22305HamburgGermany

Significant compressive stress may be induced in thin plate weldment by anti-welding heating treatment (AWHT) with a temperature difference above 350°C, which can be applied in the shipbuilding industry and an interesting phenomenon of obvious residual stress reduction on non-treated surface is discovered. The method of AWHT has not a great effect on the mechanical properties including hardness, strength and toughness of the metal material.

关键词： Experimental study Auti-welding heating treatment Thin plate weldment Welding residual stress

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核电站风险监测器软件开发研究

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核动力工程 2009年第1期30卷 26-30页

作者：王海涛吴宜灿李亚洲胡丽琴刘萍袁润曹兴焕李媛媛中国科学院等离子体物理研究所fds团队

在大型概率安全分析软件系统Risk A的基础上,开发了具有自主知识产权的核电站风险监测器Risk Angel。使用Risk Watcher及大亚湾核电站的部分参考模型对Risk Angel系统进行了测试。测试结果表明,Risk Angel完全可以用于核电站实时风险的... 详细信息

在大型概率安全分析软件系统Risk A的基础上,开发了具有自主知识产权的核电站风险监测器Risk Angel。使用Risk Watcher及大亚湾核电站的部分参考模型对Risk Angel系统进行了测试。测试结果表明,Risk Angel完全可以用于核电站实时风险的计算。

关键词：核电站概率安全评价风险监测器软件

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Bauxite washing for the removal of clay

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International Journal of Minerals,Metallurgy and Materials 2014年第11期21卷 1045-1051页

作者： Ishaq Ahmad Ernst-Ulrich Hartge Joachim Werther Reiner Wischnewski Department of Mining Engineering University of Engineering and TechnologyPeshawar-25120 Pakistan Institute of Solids Process Engineering and Particle Technology Hamburg University of Technology (TUHH)Denickestrasse 1521073 Hamburg Germany Norsk Hydro Aluminum ASA Skφyen Oslo Norway

Clay impurities associated with bauxite negatively affect the Bayer process for alumina production. These impurities should be removed as far as possible by a beneficiation technique before the ore is used as feed for the Bayer process. In this current investigation, bauxite washing was conducted in the laboratory. Bauxite washing is a physical process that causes the disintegration and deagglomeration of the clay matrix, and bauxite is liberated from the clay（mainly rich in silica）. Subsequently, separation occurs with the assistance of wet screening at a predetermined cut size. Three techniques were investigated in the laboratory： drum washing, water-jet washing, and ultrasonic washing. Various operating parameters were investigated for drum washing and water-jet washing, including materials retention time, drum rotation speed, solid concentration, water-jet spray duration, pressure, and height. We concluded that the retention time of bauxite inside the drum at a solid concentration of 55wt% and a drum rotation speed of 31 r/min is the dominant parameter for the removal of clay from the bauxite surface.

关键词： beneficiation bauxite washing clay Bayer process

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聚变堆液态金属锂铅实验回路温度测量与控制方法探索

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计量学报 2007年第z1期28卷 240-243页

作者：朱志强高胜章毛连黄群英吴宜灿徐幼斌中国科学院等离子体物理研究所fds团队安徽合肥230031 中国科学院等离子体物理研究所FDS团队安徽合肥230031 中国科学院等离子体物理研究所FDS团队安徽合肥230031 中国科学院等离子体物理研究所FDS团队安徽合肥230031 中国科学院等离子体物理研究所FDS团队安徽合肥230031 合肥易控科技有限公司安徽合肥230088

液态金属锂铅实验回路是研究聚变堆液态金属包层技术独一无二的实验平台.为了探索锂铅回路高温锂铅温度测量与控制方法,对316L不锈钢管道进行加热,并设计了其温度控制系统,以测试K型铠装热电偶不同工作端形式的测温效果.发现同一截面处... 详细信息

液态金属锂铅实验回路是研究聚变堆液态金属包层技术独一无二的实验平台.为了探索锂铅回路高温锂铅温度测量与控制方法,对316L不锈钢管道进行加热,并设计了其温度控制系统,以测试K型铠装热电偶不同工作端形式的测温效果.发现同一截面处露端式热电偶温度测量比接壳式(或绝缘式)更接近于实验设定温度,其温度曲度波动小.因此采用露端式热电偶测温方法及加热温控和数据采集系统应用于中国第一个热对流锂铅实验回路DRAGON-I,其温度测量和控制系统完全满足锂铅回路的要求.

关键词：计量学液态锂铅包层锂铅回路热电偶温度测量与控制

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Special Column on Shear Failure Test and Analysis of Concrete Structures

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Frontiers of Structural and Civil Engineering 2014年第4期8卷 323-324页

作者： Y. L. MO J. G. NIE V. SIGRIST Z. SUN University of Houston USA Tsinghua University China Hamburg University of Technology (tuhh) Germany Research Fellow Tongji University China

Shear resistance capacity analysis is a traditional bottleneck problem for the analysis and design of reinforced concrete structures. Along with the use of high performance materials and the geometrical layout optimization of concrete, rebars and other additives, the performance of reinforced concrete components and structures are continuously improved. The testing, modelling and analyzing research works are continuously conducted for the accurate computation and conservative design of the improved concrete components and structures.

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