scholarly journals A Magnetic Field Camera for Real-Time Subsurface Imaging Applications

2021 ◽  
Vol 11 (8) ◽  
pp. 3302
Author(s):  
Andriyan Bayu Suksmono ◽  
Donny Danudirdjo ◽  
Antonius Darma Setiawan ◽  
Dien Rahmawati ◽  
Rizki Putra Prastio
Keyword(s):  
Magnetic Field ◽  
Real Time ◽  
Temporal Distribution ◽  
Magnetic Flux Density ◽  
Subsurface Imaging ◽  
Interpolation Algorithm ◽  
Imaging Device ◽  
Spatio Temporal ◽  
Magneto Resistance ◽  
The Magnetic Field

We have constructed an imaging device that is capable of showing the spatio-temporal distribution of magnetic flux density in real-time. The device employs a set of AMR (anisotropic magneto-resistance) three-axis magnetometers, which are arranged into a two-dimensional sensor array. All of the magnetic field values measured by the array are collected by a microcontroller, which pre-processes and sends the data to a PDU (processing and display unit) implemented on a smartphone/tablet or a computer. The interpolation algorithm and display software in the PDU present the field as a high-resolution video; thus, the device works as a magnetic field camera. In the experiments, we employ the camera to map the field distribution of the distorted ambient magnetic field caused by a hidden object. The obtained image of field shows both the position and shape of the object. We also demonstrate the capability of the device to image a loaded power-line cable carrying a 50 Hz alternating current.

scholarly journals Solar and Stellar Dynamo Waves Under Asymptotic Investigation

1998 ◽  
Vol 167 ◽  
pp. 415-418
Author(s):  
Kirill M. Kuzanyan
Keyword(s):  
Magnetic Field ◽  
Temporal Distribution ◽  
Active Regions ◽  
Magnetic Activity ◽  
Dynamo Model ◽  
The Sun ◽  
Asymptotic Investigation ◽  
Spatio Temporal ◽  
Dynamo Wave ◽  
The Magnetic Field

AbstractThe main magnetic activity of the Sun can be visualised by Maunder butterfly diagrams which represent the spatio-temporal distribution of sunspots. Besides sunspots there are other tracers of magnetic activity, like filaments and active regions, which are observable over a wider latitudinal range of the Sun. Both these phenomena allow one to consider a complete picture of solar magnetic activity, which should be explained in the framework of one relatively simple model.A kinematic αѡ-dynamo model of the magnetic field’s generation in a thin convection shell with nonuniform helicity for large dynamo numbers is considered in the framework of Parker’s migratory dynamo. The obtained asymptotic solution of equations governing the magnetic field has a form of a modulated travelling dynamo wave. This wave propagates over the most latitudes of the solar hemisphere equatorwards, and the amplitude of the magnetic field first increases and then decreases with the propagation. Over the subpolar latitudes the dynamo wave reverses, there the dynamo wave propagates polewards and decays with latitude. Butterfly diagrams are plotted and analyzed.There is an attractive opportunity to develop a more quantitatively precise model taking into account helioseismological data on differential rotation and fitting the solar observational data on the magnetic field and turbulence, analyzing the helicity and the phase shift between toroidal and poloidal components of the field.

scholarly journals Design of a New 1D Halbach Magnet Array with Good Sinusoidal Magnetic Field by Analyzing the Curved Surface

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2522
Author(s):  
Guangdou Liu ◽  
Shiqin Hou ◽  
Xingping Xu ◽  
Wensheng Xiao
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Permanent Magnet ◽  
Flux Density ◽  
Permanent Magnets ◽  
Air Gap ◽  
Curved Surface ◽  
Magnetic Flux Density ◽  
Sinusoidal Magnetic Field ◽  
The Magnetic Field

In the linear and planar motors, the 1D Halbach magnet array is extensively used. The sinusoidal property of the magnetic field deteriorates by analyzing the magnetic field at a small air gap. Therefore, a new 1D Halbach magnet array is proposed, in which the permanent magnet with a curved surface is applied. Based on the superposition of principle and Fourier series, the magnetic flux density distribution is derived. The optimized curved surface is obtained and fitted by a polynomial. The sinusoidal magnetic field is verified by comparing it with the magnetic flux density of the finite element model. Through the analysis of different dimensions of the permanent magnet array, the optimization result has good applicability. The force ripple can be significantly reduced by the new magnet array. The effect on the mass and air gap is investigated compared with a conventional magnet array with rectangular permanent magnets. In conclusion, the new magnet array design has the scalability to be extended to various sizes of motor and is especially suitable for small air gap applications.

scholarly journals Calculation of Transient Magnetic Field and Induced Voltage in Photovoltaic Bracket System during a Lightning Stroke

2021 ◽  
Vol 11 (10) ◽  
pp. 4567
Author(s):  
Xiaoqing Zhang ◽  
Yaowu Wang
Keyword(s):  
Magnetic Field ◽  
Time Derivative ◽  
Equivalent Circuit Model ◽  
Magnetic Flux Density ◽  
Induced Voltage ◽  
Lightning Stroke ◽  
Transient Magnetic Field ◽  
Lightning Current ◽  
Time Space ◽  
The Magnetic Field

An effective method is proposed in this paper for calculating the transient magnetic field and induced voltage in the photovoltaic bracket system under lightning stroke. Considering the need for the lightning current responses on various branches of the photovoltaic bracket system, a brief outline is given to the equivalent circuit model of the photovoltaic bracket system. The analytic formulas of the transient magnetic field are derived from the vector potential for the tilted, vertical and horizontal branches in the photovoltaic bracket system. With a time–space discretization scheme put forward for theses formulas, the magnetic field distribution in an assigned spatial domain is determined on the basis of the lightning current responses. The magnetic linkage passing through a conductor loop is evaluated by the surface integral of the magnetic flux density and the induced voltage is obtained from the time derivative of the magnetic linkage. In order to check the validity of the proposed method, an experiment is made on a reduced-scale photovoltaic bracket system. Then, the proposed method is applied to an actual photovoltaic bracket system. The calculations are performed for the magnetic field distributions and induced voltages under positive and negative lightning strokes.

scholarly journals A Magnetic Field Camera for Real-Time Subsurface Imaging Applications.

2018 ◽  
Author(s):  
A.B. Suksmono ◽  
D. Danudirdjo ◽  
R.P. Prastio ◽  
A.D. Setiawan ◽  
D. Rahmawati
Keyword(s):  
Magnetic Field ◽  
Real Time ◽  
Subsurface Imaging

Uticaj armirano betonskog stuba na raspodelu magnetskog polja mešovitog voda

2020 ◽  
Vol 22 (1-2) ◽  
pp. 58-64
Author(s):  
Teodora Gavrilov ◽  
◽  
Karolina Kasaš-Lažetić ◽  
Kristian Haška ◽  
Miroslav Prša
Keyword(s):  
Magnetic Field ◽  
Field Distribution ◽  
Magnetic Field Distribution ◽  
Magnetic Flux Density ◽  
Reinforcing Bars ◽  
Magnitude Distribution ◽  
Calculation Results ◽  
Mixed Power ◽  
The Impact ◽  
The Magnetic Field

In this paper, the analysis of magnetic field distribution of overhead mixed power line (20 kV/0.4 kV) supported by reinforced concrete towers, named MNL-12 is presented. The impact of ferromagnetic, conductive parts of the pylons (reinforcing bars, billets and cross arm beams) on magnetic field distribution is investigated. The numerical calculations were performed in COMSOL Multiphysics program package on simplified 2D model. The main goal of the calculations was to examine the impact of currents induced in ferromagnetic conductive parts on magnetic field produced by currents in the power system’s conductors. The calculation results are presented graphically, as the diagrams of the magnetic flux density magnitude distribution in the tower plan, normal to the system’s axe. The calculation results demonstrated that the magnetic field of induced currents decreases the magnetic field produced by the currents of overhead power system.

Investigation on the Improvement of Surface Quality by the Magnetic Plate-Assisted Magnetic Abrasive Finishing Process

2021 ◽  
Vol 1018 ◽  
pp. 111-116
Author(s):  
Yan Hua Zou ◽  
Hui Jun Xie
Keyword(s):  
Magnetic Field ◽  
Surface Quality ◽  
Field Distribution ◽  
Magnetic Field Distribution ◽  
Magnetic Flux Density ◽  
Magnetic Pole ◽  
Magnetic Abrasive Finishing ◽  
Abrasive Finishing ◽  
Glass Lens ◽  
The Magnetic Field

The traditional magnetic abrasive finishing (MAF) process, the magnetic flux density at the bottom of the magnetic pole is unevenly distributed, resulting in poor uniformity of the finished surface. Therefore, it is proposed to improve the surface quality by attaching a magnetic plate at the bottom of the workpiece to improve the magnetic field distribution. It is confirmed by simulation that the magnetic field distribution at the bottom of the magnetic pole is effectively improved after the magnetic plate is attached. It is proved through experiments that the magnetic plate-assisted MAF process can obtain a smoother surface. The experimental results show that the surface roughness of the glass lens improves from 246 nm Ra to 3 nm Ra through the magnetic plate-assisted MAF process within 45min.

scholarly journals Noninvasive muscle activity imaging using magnetography

2020 ◽  
Vol 117 (9) ◽  
pp. 4942-4947 ◽  
Author(s):  
Rodolfo R. Llinás ◽  
Mikhail Ustinin ◽  
Stanislav Rykunov ◽  
Kerry D. Walton ◽  
Guilherme M. Rabello ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Contrast Media ◽  
Electrical Activity ◽  
Real Time ◽  
Human Body ◽  
Muscle Activity ◽  
Muscular Activity ◽  
Exponential Increase ◽  
Somatic Musculature ◽  
The Magnetic Field

A spectroscopic paradigm has been developed that allows the magnetic field emissions generated by the electrical activity in the human body to be imaged in real time. The growing significance of imaging modalities in biology is evident by the almost exponential increase of their use in research, from the molecular to the ecological level. The method of analysis described here allows totally noninvasive imaging of muscular activity (heart, somatic musculature). Such imaging can be obtained without additional methodological steps such as the use of contrast media.

Platform Design for Characterizing Shear Force Produced by Magnetized Magnetorheological Fluid

2019 ◽  
Author(s):  
Ping-Hsun Lee ◽  
Jen-Yuan (James) Chang
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Yield Stress ◽  
Flux Density ◽  
Shear Force ◽  
Permanent Magnets ◽  
Magnetic Flux Density ◽  
Finite Element Method Result ◽  
Mr Fluid ◽  
The Magnetic Field

Abstract In this paper we proposed a platform for measuring shear force of magnetorheological (MR) fluid by which the relationship of yield stress and magnetic flux density of specific material can be determined. The device consisted of a rotatable center tube in a frame body and the magnetic field was provided by two blocks of permanent magnets placed oppositely outside the frame body. The magnitude and direction of the magnetic field were manipulated by changing the distance of the two permanent magnets from the frame body and rotating the center tube, respectively. For determining the magnetic field of the device, we adopted an effective method by fitting the FEM (finite element method) result to the measured one and then rebuilt the absent components to approximate the magnetic field, which was hardly to be measured simultaneously as different device setup were required. With the proposed platform and analytical methods, the drawing shear force and the corresponding yield stress contributed by MR fluid could be evaluated in respect to the magnitude and direction of given magnetic flux density with acceptable accuracy for specific designing purposes without a large, complex, and expensive instrument.

The long-term optical activity of the propellers AE Aquarii and AR Scorpii

2020 ◽  
Vol 72 (2) ◽  
Author(s):  
Vojtěch Šimon
Keyword(s):  
Magnetic Field ◽  
Real Time ◽  
Optical Activity ◽  
White Dwarf ◽  
Transient Decrease ◽  
Mass Outflow ◽  
Orbital Modulation ◽  
The Magnetic Field

Abstract This analysis of the long-term optical activity of the propellers AE Aqr and AR Sco uses data from the Catalina Real-time Transient Survey, DASCH, and AAVSO. The site and character of the emissions from the phenomena caused by the magnetic field of the white dwarf (WD) vary from system to system. The histogram of intensities of the ensemble of flares of AE Aqr suggests that the long-term activity consists of a large variety of the peak magnitudes of the flares, with the probability of their detection gradually decreasing with increasing intensity. Any increase of activity only leads to an increase of the number of blobs of the transferring matter. We also detected a season with a transient decrease or even a cessation of the mass outflow from the donor to the lobe of the WD. The very strong orbital modulation of AR Sco is most stable in the phases of the extrema of brightness for about a century; its minor changes suggest that the trailing side of the synchrotron-emitting region is more unstable than the leading side.

2-D Magnetic Field Analysis of Air Cylinder with MR Sensor

2011 ◽  
Vol 121-126 ◽  
pp. 2706-2709
Author(s):  
Dan Jiang ◽  
Ping Yang ◽  
Kun Jiang
Keyword(s):  
Magnetic Field ◽  
Field Analysis ◽  
Magnetic Flux Density ◽  
Piston Motion ◽  
Element Analysis ◽  
Pneumatic Control ◽  
Magnetoresistive Sensor ◽  
Magnetic Field Analysis ◽  
Working Principle ◽  
The Magnetic Field

As a type of solid state switch, MR (magnetoresistive) sensor detects the air cylinder piston’s position in pneumatic control system. The construction and working principle of the air cylinder with MR sensor are introduced. Using 2-D magnetic field finite element analysis (FEA) method, the magnetic field distribution of air cylinder with piston motion is analyzed. Simulation results are given. The magnetic flux density characteristics are compared between piston wear or not.

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