Research on Distribution of Magnetic Particles Based on Magnetic Field Control Grinding Wheel

2013 ◽  
Vol 797 ◽  
pp. 428-431
Author(s):  
Shao Hui Yin ◽  
Sheng Gong ◽  
Feng Jun Chen ◽  
Ming Wang
Keyword(s):  
Magnetic Field ◽  
Surface Roughness ◽  
Magnetic Flux ◽  
Magnetic Particles ◽  
Magnetic Particle ◽  
Particle Distribution ◽  
Magnetic Flux Density ◽  
Grinding Wheel ◽  
Field Control ◽  
Orderly Arrangement

In order to solve the problem of the randomly arrangement of the diamond abrasives, a novel orderly arrangement grinding wheel was developed, which used magnetic field to control the magnetic particles to drive diamond abrasives orderly arrangement. Effects of magnetic flux density on magnetic particle distribution was studied. And effects of magnetic particle proportion on magnetic particle distribution was studied. Grinding experiments were carried out on the tungsten carbide YG8 and surface roughness after grinding was also analyzed.

Transport of Magnetic Particles Under a Uniform Magnetic Field in Microchannels

2013 ◽  
Author(s):  
Gui-Ping Zhu ◽  
Nam-Trung Nguyen
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Magnetic Flux ◽  
Flux Density ◽  
Uniform Magnetic Field ◽  
Magnetic Particles ◽  
Independent Solution ◽  
Magnetic Flux Density ◽  
Mixing Efficiency ◽  
Water Mixture

This paper reports the numerical and experimental investigation on magnetic particle concentration in a uniform magnetic field. The flow system consists of water-based ferrofluid and glycerol/DI water mixture streams. Two regimes were observed with spreading and mixing phenomena. With a low magnetic field strength, the spread of magnetic particles is caused by improved diffusion migration. With a relatively high field strength, instability at the interface would occur due to the mismatch in magnetization of the fluid streams. The transport of magnetic particles is induced by chaotic mixing of the fluids caused by a secondary flow. The mixing phenomena are characterized by magnetic flux density. For configuration with flow rate and viscosity ratio (between diamagnetic and magnetic streams) being set at 1 and 0.5, the mixing efficiency analyzed based on magnetic particles concentration increases approximately by 0.3 at around 3.5 mT. This value of magnetic flux density indicates the requirement on instability inception. The mixing efficiency increases with magnetic flux density increases further. Complete mixing can be achieved with a magnetic flux density at around 10 mT. The magnetic approach offers a wireless, heat-free and pH-independent solution for a lab-on-a-chip system.

Characterization and modeling of hard magnetic particle–based magnetorheological elastomers

2020 ◽  
pp. 1045389X2094256
Author(s):  
Nader Mohseni Ardehali ◽  
Masoud Hemmatian ◽  
Ramin Sedaghati
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Flux Density ◽  
Magnetic Particle ◽  
Excitation Frequency ◽  
Viscoelastic Behavior ◽  
Magnetic Flux Density ◽  
Driving Frequency ◽  
Magnetorheological Elastomers ◽  
Magnetic Poles

Hard magnetic particle–based magnetorheological elastomers are novel magnetoactive materials in which, unlike the soft particle–based magnetorheological elastomers, the particles provide magnetic poles inside the elastomeric medium. Therefore, the stiffness of the hard magnetic particle–based magnetorheological elastomers can be increased or decreased by applying the magnetic field in the same or opposite direction as the magnetic poles, respectively. In the present work, the viscoelastic properties of hard magnetic particle–based magnetorheological elastomers operating in shear mode have been experimentally characterized. For this purpose, hard magnetic particle–based magnetorheological elastomers with 15% volume fraction of NdFeB magnetic particles have been fabricated and then tested under oscillatory shear motion advanced rotational magneto-rheometer to investigate their viscoelastic behavior under varying excitation frequency and magnetic flux density. The influence of the shear strain amplitude and driving frequency is examined under various levels of applied magnetic field ranging from −0.2 to 1.0 T. Finally, a field-dependent phenomenological model has been proposed to predict the variation of storage and loss moduli of hard magnetic particle–based magnetorheological elastomers under varying excitation frequency and applied magnetic flux density. The results show that the proposed model can accurately predict the viscoelastic behavior of hard magnetic particle–based magnetorheological elastomers under various working conditions.

scholarly journals Development of Magnetic Particle Distribution Imaging Using Magnetic Field Reconstruction for Biopsy of the Sentinel Lymph Node

2021 ◽  
Vol 7 (6) ◽  
pp. 85
Author(s):  
Akari Inagaki ◽  
Tomoko Suzuki ◽  
Yuki Mima ◽  
Kenjiro Kimura
Keyword(s):  
Magnetic Field ◽  
Lymph Node ◽  
Sentinel Lymph Node ◽  
Magnetic Particles ◽  
Magnetic Particle ◽  
Cancer Metastasis ◽  
Particle Distribution ◽  
Magnetic Sensor ◽  
Lymphoid Tissues ◽  
Two Dimensional

The sentinel lymph node is the first lymph-node-draining cancer metastasis. The identification of the sentinel lymph node using magnetic particles and a magnetic sensor has attracted attention in recent years, as this method is less invasive than the conventional method of radiotracer injection. However, the development of a two-dimensional measurement method for sentinel lymph nodes using magnetic nanoparticles remains an issue. In the present study, a method and apparatus for the two-dimensional imaging of magnetic particle distribution were developed to detect a lymph node with magnetic particles concentrated within lymphoid tissues. The method comprises the reconstruction of the magnetic field measured with a high-sensitivity magnetic sensor and with a magnetic detection ability of 2 nT/√Hz at 100 Hz (5 nT/√Hz at 1 Hz). The proposed system measures the two-dimensional magnetic field distribution in an area of up to 25 × 25 mm2 using a coil generating a 0.77 mT external magnetic field applied to the measurement target. The improved spatial resolution of the images makes it possible to use two-dimensional imaging for diagnostics of breast cancer metastases.

A Novel Orderly Arrangement Method Controlled by Magnetic Field for Diamond Abrasives of Grinding Wheel

2012 ◽  
Vol 497 ◽  
pp. 6-9 ◽  
Author(s):  
Shao Hui Yin ◽  
Feng Jun Chen ◽  
Jian Wu Yu ◽  
Ming Wang
Keyword(s):  
Magnetic Field ◽  
Surface Roughness ◽  
Tungsten Carbide ◽  
Surface Quality ◽  
Grinding Wheel ◽  
Forming Process ◽  
Fine Grinding ◽  
The Magnetic Field ◽  
Diamond Fine ◽  
Orderly Arrangement

In traditional manufacture of grinding wheel, a key problem is the randomly arrangement of the diamond abrasives, which results in randomly distribution of surface roughness. In this paper, through controlling the magnetic field during the forming process of the grinding wheel, arrangement of diamond abrasives is orderly to obtain a more orderly surface roughness. The forming process of diamond fine grinding wheel is studied under magnetic field controlling. The grinding experiment for aspherical mold was carried out on the tungsten carbide YG8 and the surface quality after grinding was also analyzed

Manufacturing and Experimental Research of Fine Grain Diamond Grinding Wheel Based on Magnetic Field Controlling

2011 ◽  
Vol 487 ◽  
pp. 195-198 ◽  
Author(s):  
Shao Hui Yin ◽  
M. Wang ◽  
Jian Wu Yu ◽  
Feng Jun Chen ◽  
Yu Wang
Keyword(s):  
Magnetic Field ◽  
Surface Roughness ◽  
Experimental Research ◽  
Magnetic Particles ◽  
Grinding Wheel ◽  
Small Surface ◽  
Diamond Grinding Wheel ◽  
Diamond Grinding ◽  
Fine Grain ◽  
The Magnetic Field

Based on the magnetic field controlling principle, a new manufacturing method and experimental research of fine grain diamond grinding wheel were introduced. The magnetic particles could form spatial chain structures under magnetic field which can make abrasives distributed uniformly within the mold. Therefore, small surface roughness can be obtained when grinding. The manufacturing and dressing of fine grain diamond grinding wheel based on magnetic field controlling (acronym FGDWMC) were introduced. The comparison grinding tests between the magnetic field controlling and nonmagnetic field controlling of wheels were studied. The grinding experiment result showed that the surface roughness was better after being machined by FGDWMC, and it was improved by about 20nm.

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 Optical Imaging of Magnetic Particle Cluster Oscillation and Rotation in Glycerol

2021 ◽  
Vol 7 (5) ◽  
pp. 82
Author(s):  
River Gassen ◽  
Dennis Thompkins ◽  
Austin Routt ◽  
Philippe Jones ◽  
Meghan Smith ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Magnetic Particles ◽  
Magnetic Particle ◽  
Barium Hexaferrite ◽  
Optical Microscope ◽  
Simplified Model ◽  
Particle Cluster ◽  
Average Deviation ◽  
Cross Sectional

Magnetic particles have been evaluated for their biomedical applications as a drug delivery system to treat asthma and other lung diseases. In this study, ferromagnetic barium hexaferrite (BaFe12O19) and iron oxide (Fe3O4) particles were suspended in water or glycerol, as glycerol can be 1000 times more viscous than water. The particle concentration was 2.50 mg/mL for BaFe12O19 particle clusters and 1.00 mg/mL for Fe3O4 particle clusters. The magnetic particle cluster cross-sectional area ranged from 15 to 1000 μμm2, and the particle cluster diameter ranged from 5 to 45 μμm. The magnetic particle clusters were exposed to oscillating or rotating magnetic fields and imaged with an optical microscope. The oscillation frequency of the applied magnetic fields, which was created by homemade wire spools inserted into an optical microscope, ranged from 10 to 180 Hz. The magnetic field magnitudes varied from 0.25 to 9 mT. The minimum magnetic field required for particle cluster rotation or oscillation in glycerol was experimentally measured at different frequencies. The results are in qualitative agreement with a simplified model for single-domain magnetic particles, with an average deviation from the model of 1.7 ± 1.3. The observed difference may be accounted for by the fact that our simplified model does not include effects on particle cluster motion caused by randomly oriented domains in multi-domain magnetic particle clusters, irregular particle cluster size, or magnetic anisotropy, among other effects.

Effects of External Transverse Alternating Magnetic Field on the Oscillating Amplitude of Atmospheric Pressure Plasma Arc

2010 ◽  
Vol 129-131 ◽  
pp. 692-696
Author(s):  
Jian Bing Meng ◽  
Xiao Juan Dong ◽  
Chang Ning Ma
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Flux Density ◽  
Flow Rate ◽  
Gas Flow ◽  
Atmospheric Pressure Plasma ◽  
Alternating Magnetic Field ◽  
Magnetic Flux Density ◽  
Plasma Arc ◽  
Arc Current

A mathematical model was developed to describe the oscillating amplitude of the plasma arc injected transverse to an external transverse alternating magnetic field. The characteristic of plasma arc under the external transverse alternating magnetic field imposed perpendicular to the plasma current was discussed. The effect of processing parameters, such as flow rate of working gas, arc current, magnetic flux density and the standoff from the nozzle to the workpiece, on the oscillation of plasma arc were also analyzed. The results show that it is feasible to adjust the shape of the plasma arc by the transverse alternating magnetic field, which expands the region of plasma arc thermal treatment upon the workpiece. Furthermore, the oscillating amplitude of plasma arc decreases with decrease of the magnetic flux density. Under the same magnetic flux density, more gas flow rate, more arc current, and less standoff cause the oscillating amplitude to decrease. The researches have provided a deeper understanding of adjusting of plasma arc characteristics.

scholarly journals FFC NMR Relaxometer with Magnetic Flux Density Control

2019 ◽  
Vol 9 (3) ◽  
pp. 22
Author(s):  
António Roque ◽  
Duarte M. Sousa ◽  
Pedro Sebastião ◽  
Elmano Margato ◽  
Gil Marques
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Flux Density ◽  
Low Cost ◽  
Current Control ◽  
Magnetic Flux Density ◽  
Density Control ◽  
Earth Magnetic Field ◽  
Innovative Solution ◽  
Field Cycling

This paper describes an innovative solution for the power supply of a fast field cycling (FFC) nuclear magnetic resonance (NMR) spectrometer considering its low power consumption, portability and low cost. In FFC cores, the magnetic flux density must be controlled in order to perform magnetic flux density cycles with short transients, while maintaining the magnetic flux density levels with high accuracy and homogeneity. Typical solutions in the FFC NMR literature use current control to get the required magnetic flux density cycles, which correspond to an indirect magnetic flux density control. The main feature of this new relaxometer is the direct control of the magnetic flux density instead of the magnet current, in contrast with other equipment available in the market. This feature is a great progress because it improves the performance. With this solution it is possible to compensate magnetic field disturbances and parasitic magnetic fields guaranteeing, among other possibilities, a field control below the earth magnetic field. Experimental results validating the developed solution and illustrating the real operation of this type of equipment are shown.

PDMS Membrane Microactuator for Focal Tunable Microlens

2006 ◽  
Author(s):  
Seok Woo Lee ◽  
Seung S. Lee
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Flux Density ◽  
Lorentz Force ◽  
Spin Coating ◽  
Large Displacement ◽  
Pdms Membrane ◽  
Magnetic Flux Density ◽  
Optical Performance ◽  
Electrical Components

In this paper, PDMS membrane for a large displacement is fabricated by new fabrication process which can be integrated with electrical components on substrates fabricated by conventional microfabrication processes and the performance of the membrane using electromagnetism was evaluated. Rectangular PDMS membranes are designed as 2mm and 3mm in width, respectively and are actuated by Lorentz force induced by current paths spread on the membrane. The PDMS membrane is fabricated by reducing a viscosity of uncured PDMS with dilution and spin coating on the substrate on which electric components generating Lorentz force. Finally, PDMS membrane including electric components is opened by a bulk micromachining. The device is tested in magnetic field induced by Nd-Fe-B magnet whose magnetic flux density is 90G. When applied currents are 20, 25, and 30mA, the maximum deflections of membranes are 1.21, 3.07, and 20.2μm for 1.5mm width membrane and 3.34, 31.0, and 50.9μm for width 3mm membrane, respectively. The large displacement PDMS membrane actuator has potentially various applications such as fluidics, optics, acoustics, and electronics. Currently, we are planning to measure the optical performance of the actuator as a focal tunable liquid lens.

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