The Thermoelectric-Hydromagnetic Pump

1964 ◽  
Vol 86 (2) ◽  
pp. 166-168 ◽  
Author(s):  
J. F. Osterle ◽  
S. W. Angrist
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Flux ◽  
Flux Density ◽  
Pressure Rise ◽  
Maximum Efficiency ◽  
Magnetic Flux Density ◽  
Optimum Thickness ◽  
Pumping Power ◽  
Electrically Conducting

A thermally powered pump for fluids which are electrically conducting, which utilizes the Lorentz force between an electric current induced by the Seebeck effect, and an external magnetic field is examined. The pressure rise in the pump is found to be proportional to the magnetic flux density while the flow rate is found to be inversely proportional to the magnetic flux density. Thus the pumping power and efficiency (both being proportional to the product of pressure rise and flow) are independent of the applied magnetic field. Calculations for a pump with constantan walls handling sodium and utilizing a temperature difference of 300 deg C show that a maximum efficiency of close to seven-tenths of a percent is possible. If the same pump is constructed with optimum thickness walls made of the semiconductor AgSbTe2, it would have an efficiency of nearly six percent.

SURFACE BARRIER IN THE MIXED STATE OF ANISOTROPIC SUPERCONDUCTOR

1993 ◽  
Vol 07 (12) ◽  
pp. 841-847
Author(s):  
T. KRZYSZTON
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Flux ◽  
Flux Density ◽  
Magnetic Flux Density ◽  
Surface Barrier ◽  
Anisotropy Axis ◽  
Anisotropic Superconductor ◽  
Applied External Magnetic Field ◽  
London Theory

In the framework of London theory, the problem of equilibrium between magnetic flux density in the anisotropic superconductor and the applied external magnetic field is studied. The Gibbs free energy of a fluxoid in the presence of magnetic flux density in the sample is calculated. As a result, critical entry and exit fields are calculated and their dependence upon the angle which makes anisotropy axis and the direction of an external magnetic field.

External Magnetic Field Control during EDM of a Permanent Magnet

2014 ◽  
Vol 1017 ◽  
pp. 806-811
Author(s):  
Hideki Takezawa ◽  
Nobuhiro Yokote ◽  
Naotake Mohri
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Flux ◽  
Permanent Magnet ◽  
Flux Density ◽  
Electrical Discharge Machining ◽  
Magnetic Flux Density ◽  
Internal Temperature ◽  
Set Up ◽  
The Magnetic Field

The effect of changes in the magnetic field on the magnetic flux density during the electrical discharge machining (EDM) of a permanent magnet is reported. During EDM of the permanent magnet, a second magnet for the external magnetic field was set up, and the internal temperature and surface magnetic flux density on the opposite surface of the permanent magnet during machining were evaluated. It was found that even though the internal temperature of the magnet remained unchanged, the surface magnetic flux density changed when the external magnetic field was varied. In addition, the magnetic field generated by the magnet changed when a plate with high permeability was pressed onto the surface of the permanent magnet.

Properties of Photopolymer Part with Aligned Short Ferromagnetic Fibers

2016 ◽  
Vol 10 (6) ◽  
pp. 916-922 ◽  
Author(s):  
Takeshi Nakamoto ◽  
◽  
Sho Marukado ◽  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Flux ◽  
Flux Density ◽  
The Other ◽  
Magnetic Flux Density ◽  
Uv Laser ◽  
Short Fibers ◽  
The Magnetic Field ◽  
Laser Stereolithography

Photopolymer parts with short ferromagnetic fibers are fabricated by laser stereolithography. A magnetic field is applied to a liquid photopolymer that contains the short ferromagnetic fibers, with the axes of the short fibers aligned in the direction of the magnetic field. Then, the photopolymer is solidified with UV laser irradiation to get the desired shape. After fabricating the part, it is magnetized by applying magnetic field to it. When the magnetic field is applied in the direction of the aligned short fibers in the fabricated part, the residual magnetic flux density of the magnetized part in the direction of the aligned fibers becomes approximately twice that in the other directions. The magnetized part can be bent by applying an external magnetic 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.

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.

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.

Effect of distribution of magnetic flux density on purifying liquid metal by travelling magnetic field

1999 ◽  
Vol 3 (2) ◽  
pp. 157-161 ◽  
Author(s):  
Yunbo Zhong ◽  
Zhongming Ren ◽  
Kang Deng ◽  
Guochang Jiang ◽  
Kuangdi Xu
Keyword(s):  
Magnetic Field ◽  
Liquid Metal ◽  
Magnetic Flux ◽  
Flux Density ◽  
Magnetic Flux Density
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