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Lorentz Force Velocimetry for Local Velocity Measurement

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Journal of Iron and Steel Research International 2012年第S1期19卷 578-581页

作者： HEINICKE Christiane PULUGUNDLA Gautam TYMPEL Saskia BOECK Thomas KARCHER Christian SCHUMACHER Joerg RAHNEBERG Ilko FROEHLICH Thomas HILBRUNNER Falko THESS André Department of Mechanical Engineering Ilmenau University of TechnologyIlmenau 98684Germany

Standard flow measurement techniques fail for liquid metals due to their high temperatures,opaqueness and ***,recent developments in the measurement of volumetric fluxes of industrially relevant metal melts have been *** of these methods,Lorentz Force Velocimetry(LFV)is based on the measurement of Lorentz forces generated when an electrically conducting fluid moves through a magnetic *** aim is to extend the working range of this method to the measurement of local flow *** resolve local velocity fluctuations we reduce the size of the permanent magnet that produces the magnetic *** use the fundamental setup of a square duct filled with the eutectic alloy GaInSn and having a cross-section of 5 cm by 5 *** magnet cube employed has an edge length of 1 *** this setup,we investigate both experimentally and numerically the interaction between the liquid metal flow and the non-uniform magnetic *** results help in understanding the effect of flow dynamics on the total Lorentz force.

关键词： liquid metal flow measurement local resolution contactless

One-Variable Attack on the Industrial Fault Classification System and Its Defense

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Engineering 2022年第12期19卷 240-251页

作者： Yue Zhuo Yuri A.W.Shardt Zhiqiang Ge State Key Laboratory of Industrial Control technology College of Control Science and EngineeringZhejiang UniversityHangzhou 310027China Department of Automation Engineering Technische Universität IlmenauIlmenau D-98684Germany

Recently developed fault classification methods for industrial processes are mainly ***,models based on deep neural networks have significantly improved fault classification accuracy owing to the inclusion of a large number of data ***,these data-driven models are vulnerable to adversarial attacks;thus,small perturbations on the samples can cause the models to provide incorrect fault *** recent studies have demonstrated the vulnerability of machine learning methods and the existence of adversarial *** paper proposes a black-box attack method with an extreme constraint for a safe-critical industrial fault classification system:Only one variable can be perturbed to craft adversarial ***,to hide the adversarial samples in the visualization space,a Jacobian matrix is used to guide the perturbed variable selection,making the adversarial samples in the dimensional reduction space invisible to the human *** the one-variable attack(OVA)method,we explore the vulnerability of industrial variables and fault types,which can help understand the geometric characteristics of fault classification *** on the attack method,a corresponding adversarial training defense method is also proposed,which efficiently defends against an OVA and improves the prediction accuracy of the *** experiments,the proposed method was tested on two datasets from the Tennessee–Eastman process(TEP)and steel plates(SP).We explore the vulnerability and correlation within variables and faults and verify the effectiveness of OVAs and defenses for various classifiers and *** industrial fault classification systems,the attack success rate of our method is close to(on TEP)or even higher than(on SP)the current most effective first-order white-box attack method,which requires perturbation of all variables.

关键词： Adversarial samples Black-box attack Industrial data security Fault classification system

Hierarchical Sb-Ni nanoarrays as robust binder-free anodes for high-performance sodium-ion half and full cells

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Nano Research 2017年第9期10卷 3189-3201页

作者： Liying Liang Yang Xu Liaoyong Wen Yueliang Li Min Zhou Chengliang Wang Huaping Zhao Ute Kaiser Yong Lei Institute of Physics & IMN MacroNano (ZIK) Ilmenau University of Technology Professor Schmidt Strasse 26 98693 Ilmenau Germany Central Facility for Electron Microscopy Electron Microscopy Group of Materials Science UIm University Albert~Einstein-Allee 11 89081 UIm Germany

A novel hierarchical electrode material for Na-ion batteries composed of Sb nanoplates on Ni nanorod arrays is developed to tackle the issues of the rapid capacity fading and poor rate capability of Sb-based materials. The three-dimensional (3D) Sb-Ni nanoarrays as anodes exhibit the synergistic effects of the two-dimensional nanoplates and the open and conductive array structure as well as strong structural integrity. Further, their capacitive behavior is confirmed through a kinetics analysis, which shows that their excellent Na-storage performance is attributable to their unique nanostructure. When used as binder-free sodium-ion battery (SIB) anodes, the nanoarrays exhibit a high capacity retention rate (more than 80% over 200 cycles) at a current density of 0.5 A·g–1 and excellent rate capacity (up to 20 A·g–1), with their capacity being 580 mAh·g–1. Moreover, a P2-Na2/3Ni1/3Mn2/3O2//3D Sb-Ni nanoarrays full cell delivers a highly reversible capacity of 579.8 mAh·g–1 over 200 cycles and an energy density as high as 100 Wh·kg–1. This design strategy for ensuring fast and stable Na storage may work with other electrode materials as well.

关键词： hierarchical Sb-Ni nanoarrays binder-free anode capacitive charge storage Na-ion full cell

Electromagnetic Processing of Materials at the Department Inorganic-Nonmetallic Materials

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Journal of Iron and Steel Research International 2012年第S1期19卷 135-140页

作者： HALBEDEL Bernd KRIEGER Uwe WERNER Michael TORRES Jose Oskar SCHADEWALD Uwe QUIROZ Pamela ilmenau university of technology P.O. 100565D-98684 IlmenauGermany ilmenau Technische Glaswerke ilmenau GmbH Am Vogelherd 7D-98684 IlmenauGermany

This paper illustrates an overview of current research activities in the working group 'Electromagnetic Processing of Materials' of the department Inorganic-Nonmetallic *** are 'Electromagnetic module to flow impact in special melting plants for the production of High-tech glasses', 'Numerical study of EM controlled flow in crystallizers of inorganic materials', 'Design,test and optimization of sophisticated magnet systems for Lorentz force velocimetry in electrially low conducting fluids', 'Magnetic ion manipulation in glass melts with Kelvin force', 'Electromechanical dry t'me milling of raw materials' and 'Synthesis,characterization and application of Titatium doped hexaferrites'.The primary results are presented here.

关键词： Lorentz force Kelvin force magnet system glass melt crystallization grinding synthesis hexaferrite

Assembling and Test of a Halbach Array Magnet System for Lorentz Forece Velocimetry in Electrolytes

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Journal of Iron and Steel Research International 2012年第S1期19卷 145-148页

作者： Werner Michael Halbedel Bernd Department of Inorganic-Nonmetallic Materials University of Technology IlmenauIlmenau 100565 98684Germany

The paper presents a Halbach array magnet system(HAMS)for the application within a very first Lorentz force velocimetry(LFV)experiment for electrolytic *** the design,assembling procedure and characterization method are presented under consideration of the strict limited weight of the *** increase the Lorentz force outcome by a factor of three compared to the currently used simple magnet *** the fluid profile influence on a LFV measurement on electrolytes is investigated numerically-directly on the planned test setup-and presented for the first *** the Lorentz forces,generated by the HAMS,decreases by 8%comparing an ideal plug-like profile at the inlet with a semi-parabolic profile arising near the outlet of the experiment.

关键词： Lorentz force velocimetry Halbach magnet array magnet assemblies magnet system design

Flowrate Measurement in Turbulent Liquid Metal Channel Flow Using Time-of-Flight Lorentz Force Velocimetry:Experimental Investigations and Numerical Modeling

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Journal of Iron and Steel Research International 2012年第S1期19卷 582-585页

作者： JIAN Dan-dan KARCHER Christian ilmenau university of technology Institute of Thermodynamics and Fluid MechanicsIlmenau D-98684Germany

Lorentz force velocimetry(LFV)is a suitable non-contact technique to measure flow velocity and flowrates in electrically conducting high-temperature *** is based on the principles of magnetohydrodynamics:when an electrically conducting fluid passes the field lines produced by a magnet system,eddy currents are induced within the *** interactions of the eddy currents with the magnetic field generate Lorentz *** LFV the counterforce acting on the magnet system is *** a flowmeter consists of a permanent magnet system and an attached digital force *** force recorded by the flowmeter is proportional to the flowrate Q and depends on both the electrical conductivity σ of the fluid and the spatial distribution of the applied magnet field ***,in metallurgical applications,σ is often unknown or fluctuates in time as it strongly depends on both temperature and composition of the *** the present paper we investigate a technique called Time-of-Flight Lorentz force velocimetry ToF *** this technique,the flowrate can be determined by just cross-correlating the two force signals recorded by two flowmeters which are arranged one behind the other separated by a certain distance *** the passage of the triggered vortices, this ToF LFV measures the transit time τ of these *** we recalculate the velocity V according to the relation V = D/τ.We experimentally and numerically study turbulent liquid metal flow in the test facility EFCO(electromagnetic flow control channel)using the eutectic alloy GainSn as a test *** experiments show that this electromagnetic ToF LFV is well suited to determine the flow velocity and *** experiments are accompanied by numerical simulations using the commercial program package FLUENT.

关键词： Lorentz force velocimetry electromagnetic flowrate measurement magnetohydrodynamic

Lorentz Force Sigmometry

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Journal of Iron and Steel Research International 2012年第S1期19卷 123-126页

作者： Mladen Zec Robert P.Uhlig Marek Ziolkowski Hartmut Brauer Andre Thess Department of Advanced Electromagnetics Ilmenau University of TechnologyIlmenau 100565 98684 Germany Institute of Thermodynamics and Fluid Mechanics llmenau University of TechnologyIlmenau 100565 98684Germany

The present communication reports a new technique for the contactless measurement of the specific electrical conductivity of a solid conductor or an electrically conducting *** term the technique 'Lorentz Force Sigmometry' where the neologism 'Sigmometry' is derived fiom the Greek letter sigma,often used to denote the electrical *** force sigmometry(abbreviated LoFoS)is based on similar principles as the traditional eddy current testing but allows a larger penetration depth and is less sensitive to variations in the distance between the sensor and the *** we formulate the theory of LoFoS and numerically compute the calibration function which is necessary for determining the unknown electrical conductivity from the measurement of a Lorentz force.

关键词： electrical conductivity Lorentz force finite element method

Investigation of impact of DC component on breakdown characteristics for different electric fields under composite AC&DC voltage

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High Voltage 2022年第2期7卷 279-287页

作者： Mehmet Murat Ispirli Özcan Kalenderli Florian Seifert Michael Rock Bülent Oral Group for Lightning and Surge Protection Technische Universität IlmenauIlmenauGermany Electrical Engineering Department Istanbul Technical UniversityIstanbulTurkey Research Unit High‐Voltage Technologies Technische Universität IlmenauIlmenauGermany Electrical‐Electronic Engineering Department Marmara UniversityIstanbulTurkey

The valve side of the converter in the high‐voltage direct current is subjected to mixed voltages such as composite AC&DC *** this study,the effects of the homo-geneity of electric field on breakdown voltage were investigated for different�DC component amplitudes of the composite *** field efficiency factor was calcu-lated using mean and maximum field strengths for all of *** of breakdown voltage of air was examined under the composite AC&DC voltage for different ratios�*** one result of the study,the breakdown occurs at the positive half‐wave of the AC voltage despite−DC voltage being applied due to positive corona discharge *** breakdown point is named as the polarity change *** breakdown voltage increases with the decrease of DC voltage component up to polarity change point in non‐uniform electric *** less uniform electric field,the AC breakdown voltage was measured slightly higher than the DC breakdown *** less uniform electric field,as the ratio of the applied AC voltage to DC voltage increases,the breakdown voltage gradually approaches the AC breakdown *** result is similar to the result ob-tained for the+DC component in non‐uniform electric field experiments.

关键词： breakdown composite component

New Developments in Lorentz Force Velocimetry

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Journal of Iron and Steel Research International 2012年第S1期19卷 475-478页

作者： A.Thess T.Boeck S.Engert M.Gramss C.Heinicke D.Jian C.Karcher R.Klein Y.Kolesnikov V.Minchenya G.Pulugundla C.Resagk F.Santara J.Schumacher S.Tympel C.Weidermann A.Wegfrass Institute of Thermodynamics and Fluid Mechanics Ilmenau University of TechnologyIlmenau 100565 98684Germany

Lorentz force velocimetry(LFV)is a noncontact technique for the measurement of velocities in hightemperature metal melts that is based on exposing the liquid metal to a magnetic field and measuring the force acting upon the magnet system([1],[2],[3],[4]).The present communication provides an overview of recent research activities in LFV carried out at the Institute of Thermodynamics and Fluid Mechanics at ilmenau university of *** overview will focus on fundamental issues such as the suitability of LFV for local velocity measurement as well as on applications such as flow measurement in poorly conducting melts,industrial applications in aluminium production as well as on wet,dry and numerical calibration methods for *** present overview will be supplemented by individual presentations on specific topics to be presented in the papers by Heinicke,Jian,Wegfrass,Gramss,Kolesnikov and Karcher.

关键词： Flow measurement magnetohydrodynamics