• Structural Engineering and Mechanics
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• v.61 no.1
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• pp.65-76
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• 2017

Prediction of the characteristics of both in-plane and out-of-plane elastic waves within conducting nanoplates in the presence of bidirectionally in-plane magnetic fields is of interest. Using Lorentz's formulas and nonlocal continuum theory of Eringen, the nonlocal elastic version of the equations of motion is obtained. The frequencies as well as the corresponding phase and group velocities pertinent to the in-plane and out-of-plane waves are analytically evaluated. The roles of the strength of in-plane magnetic field, wavenumber, wave direction, nanoplate's thickness, and small-scale parameter on characteristics of waves are discussed. The obtained results show that the in-plane frequencies commonly grow with the in-plane magnetic field. However, the transmissibility of the out-of-plane waves rigorously depends on the magnetic field strength, direction of the propagated transverse waves, small-scale parameter, and thickness of the nanoplate. The criterion for safe transferring of the out-of-plane waves through the conducting nanoplate immersed in a bidirectional magnetic field is also explained and discussed.

• Journal of The Korean Astronomical Society
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• v.33 no.1
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• pp.47-55
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• 2000

Nonpotential characteristics of magnetic fields in AR 5747 are examined using Mees Solar Observatory magnetograms taken on Oct. 20, 1989 to Oct. 22, 1989. The active region showed such violent flaring activities during the observational span that strong X-ray flares took place including a 2B/X3 flare. The magnetogram data were obtained by the Haleakala Stokes Polarimeter which provides simultaneous Stokes profiles of the Fe I doublet 6301.5 and 6302.5. A nonlinear least square method was adopted to derive the magnetic field vectors from the observed Stokes profiles and a multi-step ambiguity solution method was employed to resolve the $180^{\circ}$ ambiguity. From the ambiguity-resolved vector magnetograms, we have derived a set of physical quantities characterizing the field configuration, which are magnetic flux, vertical current density, magnetic shear angle, angular shear, magnetic free energy density, a measure of magnetic field discontinuity MAD and linear force-free coefficient. Our results show that (1) magnetic nonpotentiality is concentrated near the inversion line in the flaring sites, (2) all the physical parameters decreased with time, which may imply that the active region was in a relaxation stage of its evolution, (3) 2-D MAD has similar patterns with other nonpotential parameters, demonstrating that it can be utilized as an useful parameter of flare producing active region, and (4) the linear force-free coefficient could be a evolutionary indicator with a merit as a global nonpotential parameter.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.181-186
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• 2005

In this paper, an estimation system of vehicle position and orientation on magnetic lane, which is a parameter of the steering controller for automated lane follwing is described. To verify that the magnetic dipole model could be applied to a magnetic unit paved in roadway, the analysis of the the data 3-axis magnetic field measured experimentally.

• Steel and Composite Structures
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• v.43 no.2
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• pp.221-228
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• 2022

Two-dimensional stagnation point slip flow of a Casson fluid impinging normally on a flat linearly shrinking surface is considered. The modeled PDEs are changed into nonlinear ODEs through appropriate nonlinear transformations.The flow is assumed to be steady and incompressible, with external magnetic field acting on it. Similarity transformation is utilized to investigate the behavior of many parameters for heat and velocity distributions using truncation approach.The influence of buoyancy parameter, slip parameter, shrinking parameter, Casson fluid parameter on the heat profile. The effect of the magnetic parameter on the streamwise velocity profile is also investigated.

• Journal of Institute of Convergence Technology
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• v.11 no.1
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• pp.7-12
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• 2021

The magnetic gear, which amplifies the torque by filtering the magnetic field generated by the low-speed permanent magnet with a modulator, can exclude gear contact and can be effectively applied when there are environmental restrictions. In this paper, we discuss the magnetic force characteristics of a magnetic gear using a magnetic focusing array that replaces a general permanent magnet array magnetized in a radial direction along the circumferential direction. The torque increasing effect of the discussed array, known as an arrangement that increases the principal component by focusing a radial magnetic field, is compared with that of a general magnetic gear. In particular, in a magnetic gear using such an array, the sensitivity of torque according to variables is analyzed to see how various variables known as factors affecting torque have an effect.

• Geomechanics and Engineering
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• v.37 no.3
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• pp.243-251
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• 2024

In the current work, a poro-thermoelastic half-space issue with temperature-dependent characteristics and an inclined load is examined in the framework of the three-phase-lag model (3PHL) while taking into account the effects of magnetic and gravity fields. The resulting coupled governing equations are non-dimensional and are solved by normal mode analysis. To investigate the impacts of the gravitational field, magnetic field, inclined load, and an empirical material constant, numerical findings are graphically displayed. MATLAB software is used for numerical calculations. Graphs are used to visualize and analyze the computational findings. It is found that the physical quantities are affected by the magnetic field, gravity field, the nonlocal parameter, the inclined load, and the empirical material constant.

• Advances in nano research
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• v.11 no.6
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• pp.581-593
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• 2021

This model is proposed to describe the buckling behavior of Carbon Nanotubes (CNTs) embedded in an elastic medium taking into account the combined effects of the magnetic field, the temperature, the nonlocal parameter, the number of walls. Using Eringen's nonlocal elasticity theory, thin cylindrical shell theory and Van der Waal force (VdW) interactions, we develop a system of partial differential equations governing the buckling response of CNTs embedded on Winkler, Pasternak, and Kerr foundations in a thermal-magnetic environment. The pre-buckling stresses are obtained by applying airy's stress function and an adjacent equilibrium criterion. To estimate the nonlocal critical buckling load of CNTs under the simultaneous effects of the magnetic field, the temperature change, and the number of walls, an optimization technique is proposed. Furthermore, analytical formulas are developed to obtain the buckling behavior of SWCNTs embedded in an elastic medium without taking into account the effects of the nonlocal parameter. These formulas take into account VdW interactions between adjacent tubes and the effect of terms involving differences in tube radii generally neglected in the derived expressions of the critical buckling load published in the literature. Most scientific research on modeling the effects of magnetic fields is based on beam theories, this motivation pushes me to develop a cylindrical shell model for studying the effect of the magnetic field on the static behavior of CNTs. The results show that the magnetic field has significant effects on the static behavior of CNTs and can lead to slow buckling. On the other hand, thermal effects reduce the critical buckling load. The findings in this work can help us design of CNTs for various applications (e.g. structural, electrical, mechanical and biological applications) in a thermal and magnetic environment.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.11
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• pp.1970-1975
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• 2008

Critical current of the superconducting machines is limited by the magnetic field. When the magnetic field is not uniform, it is difficult to estimate the magnetic field and the critical current. This paper proposed a method for the estimation of the magnetic field and the critical current of the HTS pancake windings which can be used to generate the high field magnet. A parameter which was needed to calculate the critical current of a BSCCO magnet with 10 pancake windings was obtained by the experiment. Test which was carried out by using single pancake winding and magnet consisting of 10 pancake windings shows the proposed method can be an effective method for the estimation of the critical current of pancake windings.

• Advances in materials Research
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• v.12 no.3
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• pp.243-261
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• 2023

This study aims to analyze the mechanical buckling behavior of a single-walled carbon nanotube (SWCNT) integrated with a one-parameter elastic medium and modeled as a Kerr-type foundation under a longitudinal magnetic field. The structure is considered homogeneous and therefore modeled utilizing the nonlocal first shear deformation theory (NL-FSDT). This model targets thin and thick structures and considers the effect of the transverse shear deformation and small-scale effect. The Kerr model describes the elastic matrix, which takes into account the transverse shear strain and normal pressure. Using the nonlocal elastic theory and taking into account the Lorentz magnetic force acquired from Maxwell relations, the stability equation for buckling analysis of a simply supported SWCNT under a longitudinal magnetic field is obtained. Moreover, the mechanical buckling load behavior with respect to the impacts of the magnetic field and the elastic medium parameters considering the nonlocal parameter, the rotary inertia, and transverse shear deformation was examined and discussed. This study showed useful results that can be used for the design of nano-transistors that use the buckling properties of single-wall carbon nanotubes(CNTs) due to the creation of the magnetic field effect.

• Progress in Superconductivity and Cryogenics
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• v.14 no.3
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• pp.18-22
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• 2012

This paper presents the magnetic field analysis of the racetrack double pancake field coil for the 10 MW class superconducting wind turbine which is considered to be the next generation of wind turbines using the 3 Dimensional FEM(Finite Elements Method). Generally, the racetrack-shaped field coil which is wound by the second generation(2G) superconducting wire in the longer axial direction is used, because the racetrack-shaped field coil generates the higher magnetic field density at the minimum size and reduces the synchronous reactance. To analysis the performance of the wind turbines, It is important to calculate the distribution of magnetic flux density at the straight parts and both end sections of the racetrack-shaped high temperature superconductivity(HTS) field coil. In addition, Lorentz force acting on the superconducting wire is calculated by the analysis of the magnetic field and it is important that through this way Lorentz force can be used as a parameter in the mechanical analysis which analyzes the mechanical stress on the racetrack-shaped field coil.