Numerical study of RF exposure and the resulting temperature rise in the foetus during a magnetic resonance procedure

Abstract Dynamically adjustable permanent magnet arrays have been proposed to generate switchable magnetic fields for pre-polarisation in Ultra-Low Field magnetic resonance imaging. However, the optimal switching dynamics of the pre-polarisation magnetic field as well as the energy requirements, mechanical forces and stresses during switching of the pre-polarisation field have not been evaluated. We analysed these requirements numerically and estimated the magnetic resonance signal strength and image quality for two practical switching modes in an instrument suitable for scanning the human head. Von Mises stress analysis showed that although magnetic forces were significantly higher for two specific rungs, the structural integrity of magnet rungs would not be compromised. Our simulations suggest that a significantly higher signal yield is obtained by switching off the pre-polarisation field with the angular velocity in each rung dependent on its location.

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Numerical study on temperature rise and mechanical properties of winding in oil-immersed transformer

Energy ◽

10.1016/j.energy.2021.121788 ◽

2022 ◽

Vol 239 ◽

pp. 121788 ◽

Cited By ~ 1

Author(s):

Xiaoyu Jia ◽

Mei Lin ◽

Shiwei Su ◽

Qiuwang Wang ◽

Jian Yang

Keyword(s):

Mechanical Properties ◽

Temperature Rise ◽

Numerical Study

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Numerical Study of a Crossed Loop Coil Array for Parallel Magnetic Resonance Imaging

10.1063/1.2979261 ◽

2008 ◽

Author(s):

J. Hernández ◽

S. E. Solis ◽

A. O. Rodriguez ◽

Gerardo Herrera Corral ◽

Luis Manuel Montaño Zentina

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Numerical Study ◽

Resonance Imaging ◽

Parallel Magnetic Resonance Imaging ◽

Coil Array ◽

Loop Coil

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Thermomechanical Modelling of a Steel Plate Impacted by a Shot and Experimental Validation

Materials Science Forum ◽

10.4028/www.scientific.net/msf.524-525.167 ◽

2006 ◽

Vol 524-525 ◽

pp. 167-172 ◽

Cited By ~ 1

Author(s):

Sébastien Rouquette ◽

Emmanuelle Rouhaud ◽

Hervé Pron ◽

Manuel François ◽

Christian Bissieux ◽

...

Keyword(s):

Temperature Rise ◽

Experimental Validation ◽

Steel Plate ◽

Numerical Study ◽

Infrared Camera ◽

Metallic Plate ◽

Mechanical Problem ◽

The Impact ◽

Compressive Residual Stresses ◽

Good Agreement

This work presents an experimental and numerical study of the thermo-mechanical problem of a steel plate impacted by a shot. The temperature rise is estimated and its effect on the compressive residual stress is analyzed. The simulations show that the value of the compressive residual stresses at the surface of the plate is modified when thermo-mechanical effects are included in the model as compared with simulation including hardening effects only. To validate this numerical study, an experimental device has been developed to measure the temperature rise after the impact. The experiment consists of the impact of a shot on a metallic plate. The temperature measurement is performed by an infrared camera located on the side of the plate opposite to the impact. Comparison between these experimental measurements and the numerical solution gives good agreement (to within 5%).

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