scholarly journals Numerical Model for Magnetic Fluid Hyperthermia in a Realistic Breast Phantom: Calorimetric Calibration and Treatment Planning

2019 ◽  
Vol 20 (18) ◽  
pp. 4644 ◽  
Author(s):  
Arkadiusz Miaskowski ◽  
Mahendran Subramanian
Keyword(s):  
Magnetic Field ◽  
Treatment Planning ◽  
Magnetic Fluid ◽  
Heat Dissipation ◽  
Current Effect ◽  
Magnetic Fluid Hyperthermia ◽  
Safety Issues ◽  
Tissue Interactions ◽  
Eddy Current Effect ◽  
The Magnetic Field

This paper aims to apply a proposed, based on calorimetric measurements, a reliable numerical model for magnetic fluid hyperthermia (MFH) treatment planning of breast cancer. Furthermore, we perform a comparative analysis of magnetic nanoparticles (MNPs) and tumour tissue interactions by means of the magnetic-field-dependent Néel and Brownian relaxation times. The analysis was based on an anatomically correct breast model (developed in-house) and a modified linear response theory, which was applied to investigate the heat dissipation from the magnetic nanoparticles dispersed in the breast tumour. The calculations of the single-domain magnetic power losses were conducted for a case where the magnetic field value and the applied frequency were known, but also for the different concentrations of the MNPs in the tumour. Two scenarios were considered: The MNPs mobilised and immobilised in the tumour. In parallel, the eddy currents effect, together with the related temperature distributions, were considered in order to analyse safety issues. By changing the MNP concentration in the tumour, the corresponding temperature distributions were calculated. The eddy current effect, together with the related temperature distribution, were considered in order to analyse safety issues. Varying the MNP concentration in the tumour, the corresponding temperature distribution was calculated. Moreover, the cumulative equivalent minutes at 43   ℃ were analysed. In the anatomically correct breast phantoms, the tissue location can lead to “hot spots” due to the eddy current effect and subsequently to the high gradients of the temperature. That is why the analysis of safety issues related to the overheating side effect should be taken into consideration during the treatment planning of magnetic fluid hyperthermia. The phenomenon of heat dissipation from MNPs is very sophisticated and depends on their concentration, the distribution and the relaxation mechanism in the tumour, together with magnetic field strength and frequency. Furthermore, we inferred that the phenomenon of heat dissipation from MNPs equally depends on MNP-tissue interactions, and it can lead to 30% differences in the power assessment. Nevertheless, the aforementioned factors should be considered in parallel using anatomical, volume-dependent models to enhance the efficiency of in vivo treatment.

scholarly journals Analysis and solution of eddy current induced in rail for medium and low speed maglev transportation system

2018 ◽  
Vol 4 (4) ◽  
pp. 129-137 ◽  
Author(s):  
Ying Yang ◽  
Wenyue Zhang ◽  
Laisheng Tong ◽  
Qibiao Peng ◽  
Huajun Luo ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Eddy Current ◽  
Levitation Force ◽  
Current Effect ◽  
Maglev Train ◽  
Running Speed ◽  
Low Speed ◽  
Eddy Current Effect ◽  
Maglev Transportation System ◽  
The Magnetic Field

Background: For medium and low speed maglev transportation system, the eddy current will be induced in rail, which is made of solid steel, while the train is running. The levitation force of electromagnets will be weakened by the magnetic field generated by eddy current in the rail, especially at the position of the forefront electromagnets. With the increase of train running speed, the eddy current effect will also increase, which will reach 30 % at 100 km/h, and which will directly affect the levitation stability of the train during high-speed running. Put it another way, it will limit the further improvement of the running speed of the medium and low speed maglev train. Aim: In order to solve the above problem, and compensate the levitation force reduced by the eddy current effect. Methods: The FEA method is used to obtain the magnetic field distribution and levitation force changing with the train speed. And taking the middle and low speed maglev trains and rails of Changsha Maglev Express as the research object, we have adopted two solutions, and the prototypes of airsprings and levitation magnets are manufactured and tested in the train. Results: The test result show that the currents of the windings at the front end of the two forefront electromagnets are reduced obviously. Conclusion: In this paper, the medium and low speed maglev train and rail used by Changsha Maglev Express are studied, the eddy current effect is analyzed, and two solutions are proposed. The results show that the solution methods can alleviate the eddy current effects to some extent.

On the in Vitro Hyperthermia of Magnetic Fluid in AC Magnetic Field

2009 ◽  
Author(s):  
Junfeng Jiang ◽  
Ruoyu Hong ◽  
Xiaohui Zhang ◽  
Hongzhong Li
Keyword(s):  
Magnetic Field ◽  
Magnetic Fluid ◽  
Volume Fraction ◽  
Maximum Temperature ◽  
Magnetic Fluid Hyperthermia ◽  
Ac Magnetic Field ◽  
Hyperthermia Therapy ◽  
Good Biocompatibility ◽  
High Chemical Stability

Hyperthermia therapy for cancer has attracted much attention nowadays. The study on the heat transfer in the magnetic fluid and the tumor is crucial for the successful application of magnetic fluid hyperthermia (MFH). Water-based Fe3O4 magnetic fluid is expected to be a most appropriate candidate for MFH due to the good biocompatibility, high saturation magnetization, super-paramagnetization and high chemical stability. In this paper, we explore the heat generation and transfer in magnetic fluid which is placed under an AC magnetic field. It is found that the amplitude and the frequency of alternating magnetic field, particle size and volume fraction have a pronounce influence on maximum temperature of hyperthermia.

Swirling Flow of Magnetic Fluid in Multi-Pole Rotating Magnetic Field

2003 ◽  
Author(s):  
Kenichi Kamioka ◽  
Ryuichiro Yamane
Keyword(s):  
Magnetic Field ◽  
Fluid Flow ◽  
Circular Cylinder ◽  
Phase Velocity ◽  
Magnetic Fluid ◽  
Swirling Flow ◽  
Peak Velocity ◽  
Rotating Magnetic Field ◽  
Outer Periphery ◽  
The Magnetic Field

The experiments are conducted on the magnetic fluid flow induced by the multi-pole rotating magnetic field in a circular cylinder. The numbers of poles are two, four, six, eight and twelve. The applied electric current and frequency are 2∼6 A and 20∼60 Hz, respectively. The peak velocity of the flow increases with the increase in the strength and the phase velocity of the magnetic field. As the increase in the number of poles, the flow shifts to the outer periphery.

scholarly journals Magnetic Field Generated during Electric Current-Assisted Sintering: From Health and Safety Issues to Lorentz Force Effects

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1653
Author(s):  
Huaijiu Deng ◽  
Jian Dong ◽  
Filippo Boi ◽  
Theo Saunders ◽  
Chunfeng Hu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Electric Current ◽  
Lorentz Force ◽  
Health And Safety ◽  
Interparticle Contact ◽  
Safety Issues ◽  
Contact Points ◽  
The Magnetic Field ◽  
Health And Safety Issues

In the past decade, a renewed interest on electromagnetic processing of materials has motivated several investigations on the interaction between matter, electric and magnetic fields. These effects are primarily reconducted to the Joule heating and very little attention has been dedicated to the magnetic field contributions. The magnetic field generated during electric current-assisted sintering has not been widely investigated. Magnetism could have significant effects on sintering as it generates significant magnetic forces, resulting in inductive electrical loads and preferential heating induced by overlapping magnetic fields (i.e., proximity effect). This work summarizes the magnetic field effects in electric current-assisted processing; it focuses on health and safety issues associated with large currents (up to 0.4 MA); using FEM simulations, it computes the self-generated magnetic field during spark plasma sintering (SPS) to consolidate materials with variable magnetic permeability; and it quantifies the Lorentz force acting at interparticle contact points. The results encourage one to pay more attention to magnetic field-related effects in order to engineer and exploit their potentials.

The Out-Rotator of Spin Traveling Wave Pump on Magnetic Fluid

2012 ◽  
Vol 503 ◽  
pp. 3-7
Author(s):  
Meng Zhao ◽  
Ji Bin Zou ◽  
Jing Shang
Keyword(s):  
Magnetic Field ◽  
Magnetic Fluid ◽  
Traveling Wave ◽  
Magnetic Particles ◽  
Theory Method ◽  
The Press ◽  
Relationship Of ◽  
The Relationship ◽  
The Magnetic Field

According to researching the spin traveling wave pump, the relationship of the characteristics of magnetic fluid and the press is investigated under the spin magnetic field by the theory method. The relationship of moving, magnetic field and press is investigated by the decoupled computation between the magnetic field and force. The method is scientificity and rationality by the testing. The distributing shape of magnetic fluid in the pump is affected by the adding magnetic field under the spin magnetic field when the magnetic fluid is filled in the pump. At the same time, the adding magnetic field is affected by magnetic particles of magnetic fluid. The magnetic fluid can be moved by the effect of the adding magnetic field in the pump. The flux of magnetic fluid increases with the magnetic field.

The Comparison of Magnetic Leakage of Different Teeth Structures in Magnetic Fluid Seal

2011 ◽  
Vol 197-198 ◽  
pp. 314-317 ◽  
Author(s):  
Fei Fei Xing ◽  
De Cai Li ◽  
Wen Ming Yang ◽  
Xiao Long Yang
Keyword(s):  
Magnetic Field ◽  
Finite Element Method ◽  
Finite Element ◽  
Theoretical Model ◽  
Field Distribution ◽  
Magnetic Fluid ◽  
Magnetic Field Distribution ◽  
Two Sides ◽  
The Magnetic Field ◽  
Sealing Gap

Based on the theoretical model, magnetic field distribution of rectangular teeth, two-sides dilated shape and one-side dilated shape teeth structure with common other conditions were calculated using finite element method when the sealing gap was 0.1mm and 0.12mm. The comparison of their results with the same sealing gap showed that rectangular teeth structure had the highest magnetic leakage. Moreover, the magnetic field distribution of sealing structures with rectangular stages on both the shaft and pole pieces under the same design and sealing gap were also calculated using the same method, whose result was compared with rectangular stages on pole pieces only. The comparison showed that the former did not have higher pressure capability obviously but led to higher magnetic leakage.

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