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This paper presents an analytical solution for the magnetic field between two poles of an axially oriented ring magnet. The method involves expanding the scalar potential between the two poles into McLauren series. The magnetic fi...
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This paper presents an analytical solution for the magnetic field between two poles of an axially oriented ring magnet. The method involves expanding the scalar potential between the two poles into McLauren series. The magnetic field is then linked to the field along the axis of the ring. The resulted solution shows the relationship between the geometry of the ring and magnetic field. From this solution, a geometrical relationship can be found to generate near uniform field at the center region of the ring. We also present a geometrical relationship of the ring to generate a peak field at the center. The results are then compared with boundary element analysis (BEA).
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The ReA3 reaccelerator facility at the National Superconducting Cyclotron Laboratory (NSCL), Michigan State University (MSU), East Lansing, MI, USA, provides unique access to high-quality beams of a wide variety of isotopes for sc...
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The ReA3 reaccelerator facility at the National Superconducting Cyclotron Laboratory (NSCL), Michigan State University (MSU), East Lansing, MI, USA, provides unique access to high-quality beams of a wide variety of isotopes for scientific research. The high-energy beam transport (HEBT) line from the ReA3 superconducting linear accelerator to the three experimental end stations consists of several iron-dominated normal-conducting quadrupole magnets, dipole magnets, and also combined-function horizontal and vertical corrector magnets. This article focuses on the design and fabrication of a new type of normal-conducting quadrupole magnet with cylindrical split yoke structure and standard quadrupole coils. Electromagnetic simulation results demonstrate that the magnet design fulfills the performance requirements for the ReA3 HEBT beamline. We present the coil fabrication and mechanical assembly details of the magnet. Our analysis results show that the hydraulic requirements for the coils are met.
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Part of the winding near its middle is often omitted when the volume about the centre of a solenoid over which the magnetic field is relatively uniform is to be extended. Field distributions are considered, and optimum gap lengths...
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Part of the winding near its middle is often omitted when the volume about the centre of a solenoid over which the magnetic field is relatively uniform is to be extended. Field distributions are considered, and optimum gap lengths computed. The volume of specified field uniformity is compared with hat of uniform solenoids. The use of solenoids with a gap makes certain precautions essential.
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The article describes a measurement system for magnetic field scanning using a CNC plotter. Comprehensive studies have been conducted on various materials, confirming the effectiveness and precision of the system in analysing the ...
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The article describes a measurement system for magnetic field scanning using a CNC plotter. Comprehensive studies have been conducted on various materials, confirming the effectiveness and precision of the system in analysing the uniformity distribution of the magnetic field.
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摘要 :Highlights•Permanent magnets are magnetic source suitable for exposing biological systems.•The magnetic dose is one of the most important independent factors.•Cylindrical magnets faced generate a working volume with a greater h...
展开Highlights•Permanent magnets are magnetic source suitable for exposing biological systems.•The magnetic dose is one of the most important independent factors.•Cylindrical magnets faced generate a working volume with a greater homogeneity.•The direction ofB→has greater homogeneity above the solid area in toroidal magnets.AbstractThe spatial distribution of the magnetic flux density (B) was determined for the passive sources of magnetic field most used in magnetic stimulation of biological systems, toroidal dipole magnets and cylindrical dipole magnets, in order to find the spatial characteristics of the magnetic field within the volumes of interest for the treatment of biological systems. The perpendicular and parallel components ofBregarding the polar surface of the magnets were measured, for which a FW Bell 5180 digital teslameter was used with longitudinal and transverse probes and a two-dimensional positioning system with millimeter scale. It was found that the magnets of this type, which are the most used, present a strong variation of the magnitude and direction of the magnetic flux density for spaces specified in millimeters, reason why the homogeneity of the magnetic field in the regions of interest was found to be relatively low, which makes them elements with a strong applicability for the stimulation of biological systems in which magnetic field gradients up to mT/mm are required in the case of cylindrical magnets, and up to tens of mT/mm in the case of toroidal magnets. Finally, it is concluded that a high percentage of experiments reported in the literature on magnetic treatment of biological systems may be presenting values ofBin their doses with deviations of more than 100% of the real value, which raises an incongruence in the cause-effect proposed relation.收起
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? 2022 Elsevier Ltd and Techna Group S.r.l.Manufacturing processes yielding stronger, yet lighter structures are sought for in many industries and scientific applications. Freeze casting is a fabrication process that offers a way ...
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? 2022 Elsevier Ltd and Techna Group S.r.l.Manufacturing processes yielding stronger, yet lighter structures are sought for in many industries and scientific applications. Freeze casting is a fabrication process that offers a way to achieve these strong, lightweight structures, but only in a single direction (the direction of the templating-ice growth). Applying a uniform magnetic field to these structures allows for increased strength in an additional direction, thus allowing for them to be applied in a variety of complex loading environments. Using a Helmholtz coil, it is possible to apply weak, uniform fields in any direction, magnitude, or frequency. Previous research using Helmholtz coils has shown that an applied field can increase strength through microstructural alignment, but the limited field strength reduces the applicability of these materials. To mitigate this, an oscillating field (i.e., a stronger magnetic field in a single direction with a weaker alternating field in an orthogonal direction) of various magnitudes of oscillation during the fabrication of freeze-cast materials was applied using Helmholtz coils. These oscillating magnetic fields led to an increase of strength of up to 2.5x compared to materials fabricated with either no applied field or a non-oscillating applied field due to increased alignment and thickness of the lamellar walls. This demonstrates that increased material response can be induced through the application of an oscillating field without increasing the maximum magnetic field strength.
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Magnetic-field uniformity is of the utmost importance in experiments to measure the electric dipole moment of the neutron. A general parametrization of the magnetic field in terms of harmonic polynomial modes is proposed, going be...
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Magnetic-field uniformity is of the utmost importance in experiments to measure the electric dipole moment of the neutron. A general parametrization of the magnetic field in terms of harmonic polynomial modes is proposed, going beyond the linear-gradients approximation. We review the main undesirable effects of nonuniformities: depolarization of ultracold neutrons and Larmor frequency shifts of neutrons and mercury atoms. The theoretical predictions for these effects were verified by dedicated measurements with the single-chamber neutron electricdipole- moment apparatus installed at the Paul Scherrer Institute.
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Helmholtz coils are used to establish a uniform magnetic field with the known value necessary for different applications from the technical field, such as: the calibrating of the magnetic field sensor, electromagnetic immunity (EM...
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Helmholtz coils are used to establish a uniform magnetic field with the known value necessary for different applications from the technical field, such as: the calibrating of the magnetic field sensor, electromagnetic immunity (EMI) testing research regarding the magnetic field effects against human body. Generally the practical realization of the Helmholtz coils is based on the classic study of the magnetic field, namely the magnetic field computation only on the coils axis. In this paper are shown on the basis of the magnetic field analytical computation in any point of the space (3D), that there are other domains in which the magnetic field is uniform.
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The objective of the study is a development of desk-top magnetic shielding system for the calibration of high-sensitive magnetometers, and the evaluation of their ability to produce a uniform magnetic field. This system consists o...
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The objective of the study is a development of desk-top magnetic shielding system for the calibration of high-sensitive magnetometers, and the evaluation of their ability to produce a uniform magnetic field. This system consists of hexagonal tubes and a cylinder. The hexagonal tubes have a double-layered structure, an opening and an advantage in axial shielding performance. The cylinder has openings and an advantage in transverse shielding performance. A solenoid-like coil is wound around the hexagonal tubes to produce a uniform magnetic field. From the experimental results, the magnetic shielding and the calibration field properties are demonstrated. Within the half length of the system, the achieved total magnetic field (dc component) is less than 200 nT within $pm$50 nT deviation, and the measured shielding factor is larger than 250. For producing a uniform magnetic field up to 10 kHz, we can use the 1/3 length of the system.
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The thermosolutal convection in ferromagnetic fluid is considered for a fluid layer heated and soluted from below in the presence of uniform vertical magnetic field. For the case of two free boundaries, an exact solution is obtain...
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The thermosolutal convection in ferromagnetic fluid is considered for a fluid layer heated and soluted from below in the presence of uniform vertical magnetic field. For the case of two free boundaries, an exact solution is obtained using a linear stability analysis. For the case of stationary convection, magnetization has a destabilizing effect, whereas stable solute gradient has a stabilizing effect on the onset of instability. Graphs have been plotted by giving numerical values to various parameters, to depict the stability characteristics. The principle of exchange of stabilities is found to hold true for the ferromagnetic fluid heated from below in porous medium in the absence of stable solute gradient. The oscillatory modes are introduced due to the presence of the stable solute gradient, which were non-existent in its absence. A sufficient condition for non-existence of the overstability is also obtained.
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