scholarly journals Effect of internal chain-like structures on magnetic hyperthermia in non-liquid media

2019 ◽  
Vol 377 (2143) ◽  
pp. 20180213 ◽  
Author(s):  
Andrey Yu. Zubarev
Keyword(s):  
Theoretical Study ◽  
Linear Chain ◽  
Particle Diameter ◽  
Magnetic Hyperthermia ◽  
Heating Time ◽  
Theme Issue ◽  
Magnetic Medium ◽  
Internal Structures ◽  
Magnetite Particles ◽  
Process Observation

This paper deals with a theoretical study of the effect of chain-like aggregates on magnetic hyperthermia in systems of single-domain ferromagnetic particles immobilized in a non-magnetic medium. We assume that the particles form linear chain-like aggregates and the characteristic time of the Néel remagnetization is much longer than the time of medium heating (time of process observation). This is applicable to magnetite particles when the particle diameter exceeds 20–25 nm. Our results show that the appearance of the chains significantly decreases the intensity of heat production. This article is part of the theme issue ‘Heterogeneous materials: metastable and non-ergodic internal structures’.

scholarly journals Effect of interparticle interaction on magnetic hyperthermia: homogeneous spatial distribution of the particles

2019 ◽  
Vol 377 (2143) ◽  
pp. 20180216 ◽  
Author(s):  
Ali Fathi Abu-Bakr ◽  
Andrey Zubarev
Keyword(s):  
Spatial Distribution ◽  
Magnetic Moment ◽  
Characteristic Time ◽  
Theoretical Study ◽  
Magnetic Hyperthermia ◽  
Interparticle Interaction ◽  
Theme Issue ◽  
Internal Structures ◽  
Linearly Polarized ◽  
Magnetite Particles

The paper deals with the theoretical study of the effect of magnetic interparticle interaction on magnetic hyperthermia, produced by the particles under the action of a linearly polarized oscillating field. The particles are homogeneously distributed and immobilized in a rigid medium. The supposed size of the magnetite particles is about 20–30 nm. For these particles, the characteristic time of the Neel remagnetization is much longer than the time of observation. This is why we concluded that the dissipation occurs as a result of the particle magnetic moment oscillation in the pit of energy of magnetic anisotropy. This article is part of the theme issue ‘Heterogeneous materials: metastable and non-ergodic internal structures’.

scholarly journals On the theory of magnetic hyperthermia: clusterization of nanoparticles

2020 ◽  
Vol 378 (2171) ◽  
pp. 20190251 ◽  
Author(s):  
Ali F. Abu-Bakr ◽  
Andrey Yu. Zubarev
Keyword(s):  
Mathematical Modelling ◽  
Magnetic Anisotropy ◽  
Heat Production ◽  
Theoretical Study ◽  
Magnetic Hyperthermia ◽  
Strong Anisotropy ◽  
Theme Issue ◽  
Weak Anisotropy ◽  
Host Medium ◽  
Ferromagnetic Particles

Experiments show that clusters consisting of nano-sized ferromagnetic particles strongly affect the intensity of heat production during magnetic hyperthermia. In this paper, a theoretical study and mathematical modelling of the heat production by clusters of single-domain ferromagnetic particles, immobilized in a host medium, are presented. Two situations of strong and weak magnetic anisotropy of the particles are considered. Our results show that, in the case of strong anisotropy, the clusterization weakens the thermal effect, whereas in the case of weak anisotropy it enhances it. This article is part of the theme issue ‘Patterns in soft and biological matters'.

scholarly journals The Effect of Particle Concentration on the Heating Rate of Ferrofluids for Magnetic Hyperthermia

2015 ◽  
Vol 58 (1) ◽  
pp. 81-88 ◽  
Author(s):  
I. Malaescu ◽  
C. N. Marin ◽  
M. Bunoiu ◽  
P. C. Fannin ◽  
N. Stefu ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Oleic Acid ◽  
Dilution Rate ◽  
Heating Rate ◽  
Particle Concentration ◽  
Magnetic Hyperthermia ◽  
Initial Sample ◽  
Frequency Field ◽  
Three Samples ◽  
Magnetite Particles

Abstract The complex magnetic susceptibility χ(f) = χ′(f) - i χ″(f), of a ferrofluid sample with magnetite particles dispersed in kerosene and stabilized with oleic acid, over the range 0.1 GHz to 6 GHz, was determined. The initial sample has been successively diluted with kerosene (with a dilution rate of 2/3), thus obtaining further three samples. Using the complex magnetic susceptibility measurements of each sample, the frequency field and particle concentration dependencies of the heating rate of the ferrofluid samples, were analyzed. The results show the possibility of using the heating rate of ferrofluid samples with different particle concentrations, in hyperthermia applications.

Role of Anisotropy, Frequency, and Interactions in Magnetic Hyperthermia Applications: Noninteracting Nanoparticles and Linear Chain Arrangements

2021 ◽  
Vol 15 (4) ◽  
Author(s):  
Daniela Paola Valdés ◽  
Enio Lima, ◽  
Roberto Daniel Zysler ◽  
Gerardo Fabián Goya ◽  
Emilio De Biasi
Keyword(s):  
Linear Chain ◽  
Magnetic Hyperthermia

scholarly journals STUDY ON SOME FACTORS OF MAGNETIC FLUID CHITOSANCOATED Fe3O4 NANOPARTICLES FABRICATION VIA HYDROTHERMAL METHOD

2018 ◽  
Vol 54 (2C) ◽  
pp. 341
Author(s):  
Le The Tam
Keyword(s):  
Salt Concentration ◽  
Fe3o4 Nanoparticles ◽  
Particle Diameter ◽  
Heating Time ◽  
Molar Ratio ◽  
Ferrous Ions ◽  
Hydrothermal Preparation ◽  
Hydrothermal Temperature ◽  
Synthesis Conditions ◽  
Ferric Salt

To optimize reaction conditions of hydrothermal preparation of crystalline magnetite(Fe3O4) nanoparticles, the influence of some experimental parameters (temperature, initialconcentration of ferric and ferrous ions, and heating time), and their interactions on the magneticnanoparticle formation was studied using response surface methodology (RSM), based on astatistical design of experiments (DOE). The variation in the particle diameter and crystallitesize of obtained magnetic nanoparticles (MNPs) with the synthesis conditions was examined andtransmission electron microscopy (TEM) and X-ray diffraction analysis. The results showed thatcrystallite size was greatly affected by temperature, ferric salt concentration and the heatingtime, whereas the particle diameter strongly depended on the heating time, and on the interactionbetween the initial ferrous/ferric ion molar ratio and the initial concentration of ferrous ions. TheMNPs produced by this method were the objects to coat surface with chitosan solution. Thechitosan coated MNPs are nearly spherical with a mean size from 10 to 20 nm depending on theexperimental conditions. RSM analysis showed that under optimized conditions, the chitosancoated MNPs with smallest size 13.43 ± 1.5 nm and saturation magnetization 68.12 emu/g atroom temperature were obtained under the hydrothermal temperature 165oC, heating time 2 h 55minute and ferric salt concentration 0.21 M.

Effect of ring-shaped clusters on magnetic hyperthermia: modelling approach

2021 ◽  
Vol 379 (2205) ◽  
pp. 20200316
Author(s):  
Ali F. Abu-Bakr ◽  
Andrey Yu. Zubarev
Keyword(s):  
Composite System ◽  
Magnetic Interaction ◽  
Magnetic Hyperthermia ◽  
Theme Issue ◽  
Host Medium ◽  
Closed Ring ◽  
Heterogeneous Structures ◽  
Kinetics Of ◽  
Debye Equation ◽  
Modelling Approach

Experiments demonstrate that magnetic nanoparticles, embedded in a tissue, very often form heterogeneous structures of various shapes and topologies. These structures (clusters) can significantly affect macroscopical properties of the composite system, in part its ability to generate heat under an alternating magnetic field (so-called magnetic hyperthermia). If the energy of magnetic interaction between the particles significantly exceeds the thermal energy of the system, the particles can form the closed ring-shaped clusters. In this work, we propose a relatively simple model of the heat production by the particles united in the ‘ring’ and immobilized in a host medium. Mathematically, this model is based on the phenomenological Debye equation of kinetics of the particles remagnetization. Magnetic interaction between all particles in the cluster is taken into account. Our results show that the appearance of the clusters can significantly decrease the thermal effect. This article is part of the theme issue ‘Transport phenomena in complex systems (part 1)’.

scholarly journals Anisotropic magnetic hydrogels: design, structure and mechanical properties

2019 ◽  
Vol 377 (2143) ◽  
pp. 20180217 ◽  
Author(s):  
Cristina Gila-Vilchez ◽  
Mari C. Mañas-Torres ◽  
Rafael Contreras-Montoya ◽  
Miguel Alaminos ◽  
Juan D. G. Duran ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Biomedical Applications ◽  
Magnetic Particles ◽  
Precursor Solution ◽  
Polymer Chains ◽  
Cross Linking ◽  
Theme Issue ◽  
Design Structure ◽  
Internal Structures ◽  
Intrinsic Feature

Anisotropy is an intrinsic feature of most of the human tissues (e.g. muscle, skin or cartilage). Because of this, there has been an intense effort in the search of methods for the induction of permanent anisotropy in hydrogels intended for biomedical applications. The dispersion of magnetic particles or beads in the hydrogel precursor solution prior to cross-linking, in combination with applied magnetic fields, which gives rise to columnar structures, is one of the most recently proposed approaches for this goal. We have gone even further and, in this paper, we show that it is possible to use magnetic particles as actuators for the alignment of the polymer chains in order to obtain anisotropic hydrogels. Furthermore, we characterize the microstructural arrangement and mechanical properties of the resulting hydrogels. This article is part of a theme issue ‘Heterogeneous materials: metastable and non-ergodic internal structures’.

scholarly journals A review on computational modelling of phase-transition problems

2019 ◽  
Vol 377 (2143) ◽  
pp. 20180203 ◽  
Author(s):  
Hector Gomez ◽  
Miguel Bures ◽  
Adrian Moure
Keyword(s):  
Phase Transition ◽  
Model Development ◽  
Computational Modelling ◽  
Field Method ◽  
Interfacial Phenomena ◽  
Phase Field Method ◽  
Theme Issue ◽  
Science And Engineering ◽  
Internal Structures ◽  
Numerical Discretization

Phase-transition problems are ubiquitous in science and engineering. They have been widely studied via theory, experiments and computations. This paper reviews the main challenges associated with computational modelling of phase-transition problems, addressing both model development and numerical discretization of the resulting equations. We focus on classical phase-transition problems, including liquid–solid, gas–liquid and solid–solid transformations. Our review has a strong emphasis on the treatment of interfacial phenomena and the phase-field method. This article is part of the theme issue ‘Heterogeneous materials: metastable and non-ergodic internal structures’.

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