Papers by Keyword: Lorentz Force

Abstract: This study investigated the characteristics of a microtool used in electrochemical microdrilling under conditions with and without magnetic field assistance. The experimental results indicated that charged ions and the direction of bubble movement were affected by the Lorentz force under the condition with magnetic field assistance, forming a vortex to promote electrolyte renewal. Reaction products and heat generated by the machining process were effectively discharged. The zone affected by stray current corrosion and microhole expansion were also reduced.

Abstract: Flat spiral coil for electromagnetic forming system has been modelled in FEMM 4.2 software. Copper strip was chosen as material for designing the actuator coil. Relationship between height to width ratio (S-factor) of the copper strip and coil’s performance has been studied. Magnetic field intensities, eddy currents and Lorentz force were calculated for the coils that were designed using six different 'S-factor' values (0.65, 0.75, 1.05, 1.25, 1.54 and 1.75), keeping the cross-sectional area of strip same. Results obtained through simulation suggest that actuator coil with S-factor ~ 1 shows optimum forming performance as it exerts maximum Lorentz force (84 kN) on work piece. The same coils was fabricated and used for electromagnetic sheet forming experiments. Aluminum 6061 sheets of thickness 1.5 mm have been formed using different voltage levels of capacitor bank. Smooth forming profiles were obtained with dome heights 28, 35 and 40 mm in work piece at 800, 1150 and 1250 V respectively.

Abstract: The project presents the use of laser and magnetic nanoparticles like iron oxide (Fe₃O₄) in heavy metal detection in water. In this method, metal Nanomagnets particles result in a magnetic reagent for the rapid removal of heavy metals from solutions or water of magnitude to concentration 0.25wt%. This can be done by measuring the magneto-optical parameters (as a hysteric loop) of the solution as an indication of the change in concentrations of the detected heavy metal. The samples used in this work using the Tigris River water that supported from al-Wathba lab. water projects of the Baghdad water directorate at Baghdad-Iraq. Putting here a study of the effect of graphene and metal oxide such as cobalt and nickel which doped the ferrofluid (iron oxide) /polymer/water (Tigris river water) composite on the magneto-optical properties. The graphene adding had the best result in low threshold magnetic field which was 67mGauss, give the motive to use it in fast sensing and detecting of heavy metal in Tigris river water.

Abstract: In this paper we present fabrication steps for manufacturing MEMS based magnetometer which is actuated by Lorentz force in the middle point of beam which has been fixed from both two edges (Clamped - Clamped). We utilized two different process sequences in order to fabricate microsystems properly. The structures were first fabricated on bulk Si-wafer and the fabrication of these sensors was characterized by built in stress in the beam and etching methods in the processes. The second approach was performed on SOI Si-wafer. Two fabrication routes are compared in terms of working MEMS structures. The microstructures are manufactured successfully by a process sequence based on SOI-Si wafer.

Abstract: Magnetoacoustic Tomography (MAT) is a new imaging method. MAT combines the good contrast of electrical impedance tomography with the good spatial resolution of ultrasound imaging. Magnetoacoustic Tomography includes Magnetoacoustic Tomography with magnetic induction and Magnetoacoustic Tomography with injecting current. In this paper we researched the later imaging method mainly; in paper we studied the parameters of AC power supply, which was injected to the imaging sample. At the same time, the waveforms of experiment were given and analyzed, which provides theoretical basis for the selection of power supply used in the subsequent experiments.

Abstract: Actuator based on Lorentz force exhibits excellent isolating performance with its non-contact characteristic, especially during frequency bandwidth below 5Hz. In this paper, mathematical model of the magnetic levitation actuator is constructed. In order to obtain better performance, parametric design of the structure of magnetic actuator is carried out and a multi-objective optimization method is proposed to maximize Lorentz force and minimize the mass of coil on the basis of genetic algorithm in the optimization process. A designing optimization program is developed, by which optimized parameters of magnetic actuator with maximal actuator force and minimal mass of coil can be identified to conduct experiment on ground. Compared with initial values in an instance, the optimized method is proven to be feasible and has the value of practical application.

Abstract: The left-hand rule and the right-hand rule are widely used in electromagnetics but are often confusing. Based on an analysis of the differences and commonalities of the two rules, a uniform rule using coordinate rotation is proposed to determine the direction of the magnetic force and the induced electromotive force (emf) or the induced current in a static magnetic field. Furthermore, we discuss how to use the uniform rule to determine the direction of the induced emf or current in a moving magnetic field, which is traditionally determined by Lenz's law. The uniform rule is easy to understand and remember.

Abstract: Room-temperature ionic liquids are new emerging green material. They have good chemical and thermal stability, negligible vapor pressure, nonflammability, high ionic conductivity, transparence, and a wide electrochemical window. So the ionic liquid material strongly tempts many researchers. But ionic liquids are usually applied in chemistry and rarely applied in physics. In fact ionic liquids are good photoelectric medium material owing to its well ionic conductivity, transparence. However, in applications, the drive of ionic liquids is the key technic and is also a bottle-neck. Here a kind of electromagnetic drive way is presented, There are not any mechanical moving elements and the drive is bidirectional. Theory and experiments indicate the drive pressure and flow rate are distinct undering a few voltages and 0.5T magnetic flux density. So this drive way can be used as a low power liquid pump. Latency applications in Microfluidics, Optoelectronics and industry are given.

Abstract: In this paper, an electromagnetic design method for a novel DC Lorentz Motor for micromanipulation is described. To optimize permanent magnet (PM) array and minimize the magnetic field coupling among PMs, the distribution of magnetic field and the fluctuation of Lorentz force are obtained by the 3D finite-element method (FEM). Through the electromagnetic analysis, an optimized distribution and shape of PMs are found. Finally, the optimized DC Lorentz motor is manufactured. These simulation results are verified by those of the experiment results, which presents the finite element model and simulation results are reasonable.

Abstract: Based on the electro-magneto-elastic theory and the theory of the bending vibration of the electric beam, nonlinear vibration equation of current-carrying beam in thermal-magneto-elasticity field is studied. The Lorentz force and thermal force on the beam are derived. According to the method of multiple scales for nonlinear vibrations the approximation solution of 1/3 subharmonic resonance of the system is obtained. Numerical analysis results show that the amplitude changed with the system parameters.