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AN ANALYTICAL SOLUTION FOR CALCULATING THE INITIATION OF SEDIMENT MOTION

International Journal of Sediment Research 2007年第2期22卷 87-102页

作者： Thomas LUCKNER ulrich zanke Groundwater Research Institute DresdenGermany Institute for Hydraulic Engineering Darmstadt University of TechnologyGermany

This paper presents an analytical solution for calculating the initiation of sediment motion and the risk of river bed movement. It thus deals with a fundamental problem in sediment transport, for which no complete analytical solution has yet been found. The analytical solution presented here is based on forces acting on a single grain in state of initiation of sediment motion. The previous procedures for calculating the initiation of sediment motion are complemented by an innovative combination of optical surface measurement technology for determining geometrical parameters and their statistical derivation as well as a novel approach for determining the turbulence effects of velocity fluctuations. This two aspects and the comparison of the solution functions presented here with the well known data and functions of different authors mainly differ the presented solution model for calculating the initiation of sediment motion from previous approaches. The defined values of required geometrical parameters are based on hydraulically laboratory tests with spheres. With this limitations the derivated solution functions permit the calculation of the effective critical transport parameters of a single grain, the calculation of averaged critical parameters for describing the state of initiation of sediment motion on the river bed, the calculation of the probability density of the effective critical velocity as well as the calculation of the risk of river bed movement. The main advantage of the presented model is the closed analytical solution from the equilibrium of forces on a single grain to the solution functions describing the initiation of sediment motion.

关键词： Incipient motion Initiation of sediment motion Sediment transport Bed load movement Risk analysis Risk of river bed movement Optical surface measurement

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Characteristics of developing scour-holes at a sand-embedded cylinder

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International Journal of Sediment Research 2008年第3期23卷 258-266页

作者： Oscar LINK Florian PFLEGER ulrich zanke Dept. of Civil Engineering University of Concepción Edmundo Larenas 270 Concepción Chile.Dr.-Ing. Assistant Prof. Doctoral Research Fellow Institute for Hydromechanics Technische Universitt München Arcisstrasse 21 80333 München Germany. Institute for Hydraulic and Water Resources Engineering Darmstadt University of Technology Rundeturmstraβe 1 64283 Germany.Full Prof.

Characteristics of developing scour-holes at a sand-embedded 0.2 m diameter circular cylinder are presented. Non-intrusive, high-resolution topographic measurements of developing scour-holes were made with an experimental installation using a laser distance sensor (LDS) and precision step-motors. A clear-water experiment was conducted with bed shear stress equal to 95% of the critical bed shear stress for the initiation of sediment motion at the undisturbed plane sand bed with a d50 of 0.26 mm. During the running experiment of 21 hours duration, measurements were taken by the LDS in different azimuthal half-planes with θ = 0, 15, 30, 45, 60, 75, 90, 105, 120, 135, 150, 165 and 180o in order to study the spatio-temporal variation of geometric properties in developing scour-holes. After 21 hours, the equilibrium condition was approached, with a scour rate less than d50 per hour. Measurement of maximum scour depth in different azimuthal half-planes at different points in time during the experiment show that scour started at the cylinder side and surrounded the cylinder after about 20% of experiment time. Slopes of developing scour-holes presented three regions with different inclinations, which were attributed to vortex action. Both maximum scour depth and maximum scour radius at different azimuthal half-planes are well correlated with the maximum scour depth at plane with θ = 0o. When providing maximum scour depth at the cylinder front, the presented correlations are useful for simple calculation of scour-hole topography. This work provides an experimental database for advanced numerical simulation for loose sediment hydraulics.

关键词： Scour Bridges Piers Sediment transport Loose sediment hydraulics

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紊流扩散系数与悬移质泥沙的关系

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水道港口 1984年第3期 58-60页

作者： ulrich zanke 殷风珍

根据Engelund和本文作者的研究成果,可知泥沙开始悬浮时,在水流中存在一种特定的临界速度u*1（或者u1）。计算悬移质泥沙（或浓度）分布的传统表达式给出了u*的理论分布,该值不可能小于u*1。利用u*1的存在,对一个传统的公式进行了修改... 详细信息

根据Engelund和本文作者的研究成果,可知泥沙开始悬浮时,在水流中存在一种特定的临界速度u*1（或者u1）。计算悬移质泥沙（或浓度）分布的传统表达式给出了u*的理论分布,该值不可能小于u*1。利用u*1的存在,对一个传统的公式进行了修改。此外,还指出沙质河床上的卡门常数可以大于0.4。所得出的泥沙扩散系数可以随流体与泥沙参数的不同而小于或者大于传统公式所给出的结果。同时又指出对于水流中的天然砂来说,当粒径小于0.1毫米时;传统假定εs=εw是许可的。

关键词：悬移质泥沙紊流水流流体流动方程方程式泥沙颗粒泥沙粒径

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ON THE PHYSICS OF FLOW-DRIVEN SEDIMENTS (BED-LOAD)

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International Journal of Sediment Research 2001年第1期16卷 1-18页

作者： ulrich C. E. zanke Prof, Institute of Hydraulic Engineering, University of Technology, Darmstadt, Germany Institute of Hydraulic Engineering University of Technology Darmstadt Germany

More than three dozen significant formulae for bed-load transport have been developed over a period of more than 100 years with varying degrees of success. Major problems have been the use of completely or partly empirical approaches and too few data for fitting. This paper presents an analytical formulation for bed-load transport. It is based on a balance of forces for the determination of the thickness of the moving bed-load layer and on the determination of the velocity of this layer. The formula derived is compared to a set of approx. 2000 data published by 32 authors. It is demonstrated that the basic form of the MPM-formula is a special case of the analytical solution. The derivation also includes the effect of bed features such as ripples and dunes on quantitative transport.

关键词： Bed-load transport Meyer-Peter/Mueller formula Moving bed-load layer Threshold concept Suspended load

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柱前衍生气相色谱法测定沙棘中脂肪酸的含量

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特产研究 2024年第4期46卷 116-127页

作者：赵磊丁雪孙艳杰马金刚孟军姜大成马彧昝珂长春中医药大学药学院吉林长春130117 四平市食品药品检验所吉林四平136000 吉林师范大学化学学院吉林四平136000 四平市中心人民医院吉林四平136000 吉林省医疗器械检验研究院吉林长春130041 中国食品药品检定研究院北京102629

本研究旨在建立柱前衍生-气相色谱法测定沙棘中脂肪酸的含量。采用索氏提取法提取沙棘中的脂肪油,甲酯化后,采用气相色谱法测定沙棘中脂肪酸成分。结果表明,柱前衍生测定的肉豆蔻酸、棕榈酸、棕榈油酸、硬脂酸、油酸、亚油酸、α-亚麻... 详细信息

本研究旨在建立柱前衍生-气相色谱法测定沙棘中脂肪酸的含量。采用索氏提取法提取沙棘中的脂肪油,甲酯化后,采用气相色谱法测定沙棘中脂肪酸成分。结果表明,柱前衍生测定的肉豆蔻酸、棕榈酸、棕榈油酸、硬脂酸、油酸、亚油酸、α-亚麻酸线性范围良好,r均大于0.999 8;平均回收率均大于93.1%,RSD均小于2.8%;通过Spass软件分析沙棘果不同部位的种子、果皮、果肉分别被聚为一类表明3种药用部位的脂肪酸类成分可以分别作为鉴别沙棘不同部位的重要指标成分。其中种子中的亚油酸含量约为果肉、果皮的2倍,α-亚麻酸含量种子中高于果肉、果皮15倍以上通过棕榈酸与棕榈油酸的比值判断,随着贮藏时间的增长棕榈酸与棕榈油酸的比值越大;沙棘果在通过蒸制20min后干燥处理,脂肪酸类成分含量最佳。通过柱前衍生-气相色谱法测定沙棘中脂肪酸的含量,可用于沙棘的质量评价。

关键词：沙棘脂肪酸气相色谱柱前衍生

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ON THE INFLUENCE OF TURBULENCE ON THE INITIATION OF SEDIMENT MOTION

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International Journal of Sediment Research 2003年第1期18卷 17-31页

作者： U.C.E. zanke Darmstadt Germany Institute of Hydraulic Engineering Prof University of Technology

For the initiation of sediment motion a theory is developed, which presupposes that the critical shear stress tc responsible for inducing motion in non-turbulent flow is solely defined by the angle of internal friction f or the angle of repose f’ of single grains. In turbulent flow, fluctuations t’ in the shear stress as well as lift forces produced by these fluctuations also occur. Owing to this, the actual (effective) critical shear stress t + t’ acting on a grain is larger than the average stress t on the one hand, and on the other hand, the effective weight of the grains is reduced: they become effectively lighter. On the basis of the presented analytical formulation the initiation of sediment motion may be described solely by the angle of repose of the grains and turbulence parameters.

关键词： Critical shear stress Angle of repose Initiation of sediment motion Turbulence parameter

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In vitro Antimicrobial Activity and Phytochemical Screening of Local Plants

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Journal of Pharmacy and Pharmacology 2016年第4期4卷 151-154页

作者： Shital Chandrashekhar Lolge Sunita Pandit zanke Dipfi Ramrao Patil Sureshchandra Popat Zambare Department of Zoology Dr. BabasahebAmbedkarMarathwada University Aurangabad 431004 (M.S.) India

Antimicrobial activity of extracts of local plants was evaluated, with two strain i.e E. coil and S. aurri （gram positive and gram negative） microorganisms. The in vitro anti bacterial activity was performed by agar disc diffusion method. The most active antibacterial plants were S. trifiliatus and A. mexicana. The significant antibacterial activity of active extracts was compared with the standered, antimicrobics, streptomycin （10 μg/disc）. The results obtained in the present study suggest that S. trifoliatus and A. mexicana can be used in treating diseases caused by the test organism.

关键词： Antimicrobial antibacterial plant extract S. trifoliatus A. mexicana.

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WORLD ASSOCIATION FOR SEDIMENTATION AND EROSION RESEARCH (WASER)

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International Journal of Sediment Research 2016年第2期 94-94页

作者： Giampaolo Di Silvio ulrich C.E.zanke Zhao-yin Wang

The World Association for Sedimentation and Erosion Research(WASER),inaugurated on Oct.19,2004,is an independent non-governmental,non-profit *** mission of WASER is to promote international co-operation on the study a... 详细信息

关键词： WORLD ASSOCIATION FOR SEDIMENTATION AND EROSION RESEARCH WASER

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壮药材滇桂艾纳香及其易混品种东风草和高艾纳香比较研究

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中国药事 2020年第2期34卷 169-183页

作者：林雀跃张荣林甘勇强黄清泉唐琳娜郑健过立农昝珂谢培德广西壮族自治区食品药品检验所南宁530021 广西-东盟食品药品安全检验检测中心南宁530021 中国食品药品检定研究院北京100050

目的:建立壮药材滇桂艾纳香专属性检验方法。方法:采用基原鉴别、性状鉴别、显微鉴别、薄层鉴别、分子生物学及特征图谱等方法对滇桂艾纳香及其易混品种东风草和高艾纳香进行对比研究。结果:三者的根、茎、叶性状基本相同,区别点在于滇... 详细信息

目的:建立壮药材滇桂艾纳香专属性检验方法。方法:采用基原鉴别、性状鉴别、显微鉴别、薄层鉴别、分子生物学及特征图谱等方法对滇桂艾纳香及其易混品种东风草和高艾纳香进行对比研究。结果:三者的根、茎、叶性状基本相同,区别点在于滇桂艾纳香头状花序小(直径0.5~0.8 cm),东风草头状花序大(直径1.5~2 cm),高艾纳香头状花序具密集的长绒毛;三者的根、茎横切面,粉末显微特征基本相同,高艾纳香具基部膨大的非腺毛;薄层鉴别(1)中高艾纳香比滇桂艾纳香和东风草少1个斑点;薄层鉴别(2)中滇桂艾纳香比东风草和高艾纳香少1个特征斑点;ITS2序列N-J树聚类分析显示三者具有良好的单系性,三者种间最小遗传距离均大于种内最大遗传距离;与滇桂艾纳香对照图谱相比,东风草平均相似度为0.962,高艾纳香平均相似度仅为0.789。结论:高艾纳香与滇桂艾纳香区别较大,不宜混用,在日常使用中应注意甄别;东风草与滇桂艾纳香在性状、显微、薄层、分子生物学、特征图谱等方面相似度较高,在对二者进行充分的药理活性以及临床试验等基础上,可考虑作为滇桂艾纳香的替代品使用,以缓解药用资源不足的问题。

关键词：滇桂艾纳香东风草高艾纳香性状鉴别显微鉴别薄层鉴别分子生物学特征图谱

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