Nikolaos Maniotis will present a poster on numerical simulations of interactions between magnetic nanoparticles (MNPs) and living matter. The interactions occur under varying external magnetic fields and frequencies through two experimental setups: (1) MNPs transform magnetic energy into mechanical forces on cancer cells via magnetic field gradients from permanent magnets, decreasing cell viability; (2) MNPs transform magnetic energy into heat through magnetic hyperthermia using alternating magnetic fields, inducing apoptosis. Simulations analyze MNP heating and thermal dissipation based on shape and coating. They also model the experimental setups using COMSOL Multiphysics to calculate magnetic fields, temperature distributions, and solve coupled physics phenomena.
In this paper, the natural convection heat transfer process is investigated inside an annular enclosure filled with a magnetic nanofluid (Fe3O4 magnetic nanoparticles dispersed in Kerosene). A uniform magnetic field (H) is applied along the axial direction of the enclosure. Thermal conductivity (k) is considered as a function of magnetic field. A nonlinear relationship between magnetic field and thermal conductivity in the magnetic nanofluid (MNF) is assumed and interpolated. Finite element method is utilized to solve the governing equations and calculate the Nusselt number and it is presented as a function of volume fraction and magnetic field strength. The results show the significant effect of applied magnetic field on heat transfer rate, more specifically on Nu, in the enclosure when higher volume fractions of nanoparticles are used. Thermal conductivity enhancement as a result of using magnetic field can be used for various applications such as thermal energy storage in which the heat transfer needs to be accurately controlled.
FERROMAGNETIC-FERROELECTRIC COMPOSITE 1D NANOSTRUCTURE IN THE PURSUIT OF MAGN...ijrap
Nanocomposites of linear chain of ferroelectric-ferromagnetic crystal structure is considered. It is analyzed
theoretically in the motion equation method on the pursuit of magnonic excitations,lattice vibration
excitations and their interactions leading to a new collective mode of excitations,the electormagnons. In
this particular work, it is observed that the magnetizations and polarizations are tunable in a given temperature ranges for some specific values of the coupling order parameter.
Ferromagnetic-Ferroelectric Composite 1D Nanostructure in the Pursuit of Magn...ijrap
Nanocomposites of linear chain of ferroelectric-ferromagnetic crystal structure is considered. It is analyzed
theoretically in the motion equation method on the pursuit of magnonic excitations,lattice vibration
excitations and their interactions leading to a new collective mode of excitations,the electormagnons. In
this particular work, it is observed that the magnetizations and polarizations are tunable in a given
temperature ranges for some specific values of the coupling order parameter
The Monte Carlo Method of Random Sampling in Statistical PhysicsIOSR Journals
The Monte Carlo technique of random sampling was reviewed in this work. It plays an important role in Statistical Mechanics as well as in scientific computation especially when problems have a vast phase space. The purpose of this paper is to review a general method, suitable to fast electronic computing machines, for calculating the properties of any system which may be considered as composed of interacting particles. Concepts such as phase transition, the Ising model,ergodicity, simple sampling, Metropolis algorithm, quantum Monte Carlo and Non-Boltzmann sampling were discussed. The applications of Monte Carlo method in other areas of study aside Statistical Physics werealso mentioned.
Effect of Rotation on a Layer of Micro-Polar Ferromagnetic Dusty Fluid Heated...IJERA Editor
This paper deals with the theoretical investigation of effect of rotation on micro-polar ferromagnetic dusty fluid
layer heated from below in a porous medium. Linear stability analysis and normal mode analysis methods are
used to find an exact solution for a flat micro-polar ferromagnetic fluid layer contained between two free
boundaries . In case of stationary convection, the effect of various parameters like medium permeability
parameter, non-buoyancy magnetization parameter, micro-polar coupling parameter, spin-diffusion parameter,
micro-polar heat conduction parameter, dust particles parameter and rotation parameter has been analyzed and
results are depicted graphically. In the absence of dust particles, rotation, micro-viscous effect and micro-inertia,
the sufficient condition is obtained for non-oscillatory modes
In this paper, the natural convection heat transfer process is investigated inside an annular enclosure filled with a magnetic nanofluid (Fe3O4 magnetic nanoparticles dispersed in Kerosene). A uniform magnetic field (H) is applied along the axial direction of the enclosure. Thermal conductivity (k) is considered as a function of magnetic field. A nonlinear relationship between magnetic field and thermal conductivity in the magnetic nanofluid (MNF) is assumed and interpolated. Finite element method is utilized to solve the governing equations and calculate the Nusselt number and it is presented as a function of volume fraction and magnetic field strength. The results show the significant effect of applied magnetic field on heat transfer rate, more specifically on Nu, in the enclosure when higher volume fractions of nanoparticles are used. Thermal conductivity enhancement as a result of using magnetic field can be used for various applications such as thermal energy storage in which the heat transfer needs to be accurately controlled.
FERROMAGNETIC-FERROELECTRIC COMPOSITE 1D NANOSTRUCTURE IN THE PURSUIT OF MAGN...ijrap
Nanocomposites of linear chain of ferroelectric-ferromagnetic crystal structure is considered. It is analyzed
theoretically in the motion equation method on the pursuit of magnonic excitations,lattice vibration
excitations and their interactions leading to a new collective mode of excitations,the electormagnons. In
this particular work, it is observed that the magnetizations and polarizations are tunable in a given temperature ranges for some specific values of the coupling order parameter.
Ferromagnetic-Ferroelectric Composite 1D Nanostructure in the Pursuit of Magn...ijrap
Nanocomposites of linear chain of ferroelectric-ferromagnetic crystal structure is considered. It is analyzed
theoretically in the motion equation method on the pursuit of magnonic excitations,lattice vibration
excitations and their interactions leading to a new collective mode of excitations,the electormagnons. In
this particular work, it is observed that the magnetizations and polarizations are tunable in a given
temperature ranges for some specific values of the coupling order parameter
The Monte Carlo Method of Random Sampling in Statistical PhysicsIOSR Journals
The Monte Carlo technique of random sampling was reviewed in this work. It plays an important role in Statistical Mechanics as well as in scientific computation especially when problems have a vast phase space. The purpose of this paper is to review a general method, suitable to fast electronic computing machines, for calculating the properties of any system which may be considered as composed of interacting particles. Concepts such as phase transition, the Ising model,ergodicity, simple sampling, Metropolis algorithm, quantum Monte Carlo and Non-Boltzmann sampling were discussed. The applications of Monte Carlo method in other areas of study aside Statistical Physics werealso mentioned.
Effect of Rotation on a Layer of Micro-Polar Ferromagnetic Dusty Fluid Heated...IJERA Editor
This paper deals with the theoretical investigation of effect of rotation on micro-polar ferromagnetic dusty fluid
layer heated from below in a porous medium. Linear stability analysis and normal mode analysis methods are
used to find an exact solution for a flat micro-polar ferromagnetic fluid layer contained between two free
boundaries . In case of stationary convection, the effect of various parameters like medium permeability
parameter, non-buoyancy magnetization parameter, micro-polar coupling parameter, spin-diffusion parameter,
micro-polar heat conduction parameter, dust particles parameter and rotation parameter has been analyzed and
results are depicted graphically. In the absence of dust particles, rotation, micro-viscous effect and micro-inertia,
the sufficient condition is obtained for non-oscillatory modes
Comparative Study of Evolutionary Algorithms for the Optimum Design Of Thin B...jmicro
With the increasing levels of Electromagnetic pollution almost exponentially in this modern age of
Electronics reported and highlighted by numerous studies carried out by scientists from all over the world,
inspire engineers to concentrate their research for the optimum design of multilayer microwave absorber
considering various parameters which are inherently conflicting in nature. In this paper we mainly focus
on the comparative study of different Evolutionary algorithms for the optimum design of thin broadband (2-
20GHz) multilayer microwave absorber for oblique incidence (300
) considering arbitrary polarization of
the electromagnetic waves. Different models are presented and synthesized using various Evolutionary
algorithm namely Firefly algorithm (FA), Particle swarm optimization (PSO), Artificial bee colony
optimization (ABC) and the best simulated results are tabulated and compared with each others.
Influence of Interface Thermal Resistance on Relaxation Dynamics of Metal-Die...A Behzadmehr
Nanocomposite materials, including noble metal nanoparticles embedded in a dielectric host medium, are interesting because of their optical properties linked to surface plasmon resonance phenomena. For studding of nonlinear optical properties and/or energy transfer process, these materials may be excited by ultrashort pulse laser with a temporal width varying from some femtoseconds to some hundreds of picoseconds. Following of absorption of light energy by metal-dielectric nanocomposite material, metal nanoparticles are heated. Then, the thermal energy is transferred to the host medium through particle-dielectric interface. On the one hand, nonlinear optical properties of such materials depend on their thermal responses to laser pulse, and on the other hand different parameters, such as pulse laser and medium thermodynamic characterizes, govern on the thermal responses of medium to laser pulse. Here, influence of thermal resistance at particle-surrounding medium interface on thermal response of such material under ultrashort pulse laser excitation is investigated. For this, we used three temperature model based on energy exchange between different bodies of medium. The results show that the interface thermal resistance plays a crucial role on nanoparticle cooling dynamics, so that the relaxation characterized time increases by increasing of interface thermal resistance.
Micromechanical Modeling of the Macroscopic Behavior of Soft Ferromagnetic Co...IJMERJOURNAL
ABSTRACT: Soft ferromagnetic composites consist of ferromagnetic particles embedded within nonmagnetic electrically insulating matrix. The aims of this article are twofold. In the first one, multiaxial nonlinear isothermal constitutive equations that govern the behavior of soft ferromagnetic materials are generalized to include the temperature and hysteretic effects. The second aim consists of developing a micromechanical analysis which takes into account the detailed interaction between the phases, and establishes the instantaneous concentration tensors which relate between the local magneto-thermo-elastic field and the externally applied loading. The ferromagnetic particles constituents employed in the micromechanical analysis are governed by the developed magneto-thermo-elastic coupled hysteretic constitutive relations. With the established concentration tensors, the macroscopic (global) re- sponse of the composite can be readily determined at any instant of loading. The offered micromechanical modeling is capable of predicting the response of soft ferromagnetic composites that are subjected to various types of magneto-thermo-elastic loadings, and it can be employed by the designerto easily determine the composite response for a particular desired application.
Introduction to Magnetic RefrigerationSamet Baykul
DATE: 2019.06
We have given a lecture to the class in the course of "Refrigeration Systems" in ODTÜ.
Refrigeration technology has an important role over various areas such as medicine, food, manufacturing, and it is a very important element for a comfortable life for the society. It directly affects the people’s life by permiting to store the medicines and foods for long times, manufacturing with very high accuracy, air conditioning applications, etc.
Although refrigeration technology have lots of benefits which has been mentioned above, conventional vapor compression/expansion systems have some weaknesses. Refrigerant fluids that are used in the traditional cooling/refrigeration applications have important effects over the global warming and ozone depletion. To be able to overcome these disadvantages of the refrigeration applications, new thecnologies which does not use harmful matirals such as traditional refrigerants are investigated. One of these developing technologies is magnetic refrigeration systems.
Magnetic refrigeration systems are commonly used in the low temperature applications and it also has usage in air conditioning applications, aerospace technologies and telecommunication technologies.
Magnetic refrigeration has lots of advantages such that:
1. It uses very small amount of energy compared to compressor work inlet of a similar size vapor compression/expansion system.
2. It is highly more compact and makes less noise than the traditional systems.
3. It has a lower operating and maintenance cost.
4. It is environment friendly and does not cause the global warming or ozone depletion.
Although the magnetic refrigeration has lots of benefits which have been described above, because of its high initial cost and need of the very rare materials in the system, it is not very common recent days, however, it has a high potential for the future.
Numerical Model of Microwave Heating in a Saturated Non-Uniform Porosity Medi...drboon
The microwave heating of a porous medium with a non-uniform porosity is numerically investigated, based on the proposed numerical model. A variation of porosity of the medium is considered. The generalized non-Darcian model developed takes into account of the presence of a solid drag and the inertial effect. The transient Maxwell’s equations are solved by using the finite difference time domain (FDTD) method to describe the electromagnetic field in the wave guide and medium. The temperature profile and velocity field within a medium are determined by the solution of the momentum, energy and Maxwell’s equations. The coupled non-linear set of these equations are solved using the SIMPLE algorithm. In this work, a detailed parametric study is conducted for a heat transport inside a rectangular enclosure filled with saturated porous medium of constant or variable porosity. The numerical results agree well with the experimental data. Variations in porosity significantly affect the microwave heating process as well as convective flow pattern.
During the last decades a large effort has been invested in the development of a new
discipline devoted to benefit from optical excitations in materials where metals are
key element (Plasmonics). We will make an introduction on this topic below, but let’s
anticipate that two application areas are sensing and information technologies.
The following height extended abstracts, presented during the one-day NANOMAGMA
Symposium (Bilbao, Spain – April 13, 2011 reflects some of the latest developments on magneto-plasmonics.
In 2010 and 2011, the nanoICT project (EU/ICT/FET Coordination Action) launched
two calls for exchange visits for PhD students with the following main objectives: 1.
To perform joint work or to be trained in the leading European industrial and academic research institutions; 2. To enhance long-term collaborations within the ERA; 3. To
generate high-skilled personnel and to facilitate technology transfer;
The first outcome report was published in the issue 22 (August 2011) and this edition
contains four new articles providing insights in relevant fi elds for nanoICT.
We would like to thank all the authors who contributed to this issue as well as the European Commission for the financial support (projects nanoICT No. 216165 and NANOMAGMA No. FP7-214107-2).
Dr. Antonio Correia Editor - Phantoms Foundation
Interior Heating of Rocky Exoplanets from Stellar Flares with Application to ...Sérgio Sacani
Many stars of different spectral types with planets in the habitable zone are known to emit flares. Until now, studies
that address the long-term impact of stellar flares and associated coronal mass ejections (CMEs) assumed that the
planet’s interior remains unaffected by interplanetary CMEs, only considering the effect of plasma/UV
interactions on the atmosphere of planets. Here, we show that the magnetic flux carried by flare-associated CMEs
results in planetary interior heating by ohmic dissipation and leads to a variety of interior–exterior interactions. We
construct a physical model to study this effect and apply it to the TRAPPIST-1 star whose flaring activity has been
constrained by Kepler observations. Our model is posed in a stochastic manner to account for uncertainty and
variability in input parameters. Particularly for the innermost planets, our results suggest that the heat dissipated in
the silicate mantle is both of sufficient magnitude and longevity to drive geological processes and hence facilitate
volcanism and outgassing of the TRAPPIST-1 planets. Furthermore, our model predicts that Joule heating can
further be enhanced for planets with an intrinsic magnetic field compared to those without. The associated
volcanism and outgassing may continuously replenish the atmosphere and thereby mitigate the erosion of the
atmosphere caused by the direct impact of flares and CMEs. To maintain consistency of atmospheric and
geophysical models, the impact of stellar flares and CMEs on atmospheres of close-in exoplanetary systems needs
to be studied in conjunction with the effect on planetary interiors.
magnetic fluid generator, manuscript prepared for 2nd GCMEA 2012 Hilton Longbeach USA. selected one of publish planning presentation abstracts. (already published in a proceedings)
Hysteresis Loops for Magnetoelectric Multiferroics Using Landau-Khalatnikov T...IJECEIAES
We present a theoretical discussion of the hysteresis in magnetoelectric multiferroics with bi-quadratic magnetoelectric coupling. The calculations were performed by employing Landau-Khalatnikov equation of motion for both the ferroelectric and ferromagnetic phase, then solve it simultaneously. In magnetoelectric, we obtain four types of hysteresis: ferroelectric hysteresis, ferromagnetic hysteresis and two types of cross hysteresis (electric field versus magnetization and magnetic field versus electric polarization). The cross hysteresis has butterfly shape which agree with the result from the previous research. It can also be seen from that hysteresis, that magnetization / electric polarization can not be flipped into the opposite direction using external electric / magnetic field when the magnetoelectric coupling is bi-quadratic type. Overall, the result shows that LandauKhalatnikov equation is able to approximate hysteresis loops in multiferroics system.
Comparative Study of Evolutionary Algorithms for the Optimum Design Of Thin B...jmicro
With the increasing levels of Electromagnetic pollution almost exponentially in this modern age of
Electronics reported and highlighted by numerous studies carried out by scientists from all over the world,
inspire engineers to concentrate their research for the optimum design of multilayer microwave absorber
considering various parameters which are inherently conflicting in nature. In this paper we mainly focus
on the comparative study of different Evolutionary algorithms for the optimum design of thin broadband (2-
20GHz) multilayer microwave absorber for oblique incidence (300
) considering arbitrary polarization of
the electromagnetic waves. Different models are presented and synthesized using various Evolutionary
algorithm namely Firefly algorithm (FA), Particle swarm optimization (PSO), Artificial bee colony
optimization (ABC) and the best simulated results are tabulated and compared with each others.
Influence of Interface Thermal Resistance on Relaxation Dynamics of Metal-Die...A Behzadmehr
Nanocomposite materials, including noble metal nanoparticles embedded in a dielectric host medium, are interesting because of their optical properties linked to surface plasmon resonance phenomena. For studding of nonlinear optical properties and/or energy transfer process, these materials may be excited by ultrashort pulse laser with a temporal width varying from some femtoseconds to some hundreds of picoseconds. Following of absorption of light energy by metal-dielectric nanocomposite material, metal nanoparticles are heated. Then, the thermal energy is transferred to the host medium through particle-dielectric interface. On the one hand, nonlinear optical properties of such materials depend on their thermal responses to laser pulse, and on the other hand different parameters, such as pulse laser and medium thermodynamic characterizes, govern on the thermal responses of medium to laser pulse. Here, influence of thermal resistance at particle-surrounding medium interface on thermal response of such material under ultrashort pulse laser excitation is investigated. For this, we used three temperature model based on energy exchange between different bodies of medium. The results show that the interface thermal resistance plays a crucial role on nanoparticle cooling dynamics, so that the relaxation characterized time increases by increasing of interface thermal resistance.
Micromechanical Modeling of the Macroscopic Behavior of Soft Ferromagnetic Co...IJMERJOURNAL
ABSTRACT: Soft ferromagnetic composites consist of ferromagnetic particles embedded within nonmagnetic electrically insulating matrix. The aims of this article are twofold. In the first one, multiaxial nonlinear isothermal constitutive equations that govern the behavior of soft ferromagnetic materials are generalized to include the temperature and hysteretic effects. The second aim consists of developing a micromechanical analysis which takes into account the detailed interaction between the phases, and establishes the instantaneous concentration tensors which relate between the local magneto-thermo-elastic field and the externally applied loading. The ferromagnetic particles constituents employed in the micromechanical analysis are governed by the developed magneto-thermo-elastic coupled hysteretic constitutive relations. With the established concentration tensors, the macroscopic (global) re- sponse of the composite can be readily determined at any instant of loading. The offered micromechanical modeling is capable of predicting the response of soft ferromagnetic composites that are subjected to various types of magneto-thermo-elastic loadings, and it can be employed by the designerto easily determine the composite response for a particular desired application.
Introduction to Magnetic RefrigerationSamet Baykul
DATE: 2019.06
We have given a lecture to the class in the course of "Refrigeration Systems" in ODTÜ.
Refrigeration technology has an important role over various areas such as medicine, food, manufacturing, and it is a very important element for a comfortable life for the society. It directly affects the people’s life by permiting to store the medicines and foods for long times, manufacturing with very high accuracy, air conditioning applications, etc.
Although refrigeration technology have lots of benefits which has been mentioned above, conventional vapor compression/expansion systems have some weaknesses. Refrigerant fluids that are used in the traditional cooling/refrigeration applications have important effects over the global warming and ozone depletion. To be able to overcome these disadvantages of the refrigeration applications, new thecnologies which does not use harmful matirals such as traditional refrigerants are investigated. One of these developing technologies is magnetic refrigeration systems.
Magnetic refrigeration systems are commonly used in the low temperature applications and it also has usage in air conditioning applications, aerospace technologies and telecommunication technologies.
Magnetic refrigeration has lots of advantages such that:
1. It uses very small amount of energy compared to compressor work inlet of a similar size vapor compression/expansion system.
2. It is highly more compact and makes less noise than the traditional systems.
3. It has a lower operating and maintenance cost.
4. It is environment friendly and does not cause the global warming or ozone depletion.
Although the magnetic refrigeration has lots of benefits which have been described above, because of its high initial cost and need of the very rare materials in the system, it is not very common recent days, however, it has a high potential for the future.
Numerical Model of Microwave Heating in a Saturated Non-Uniform Porosity Medi...drboon
The microwave heating of a porous medium with a non-uniform porosity is numerically investigated, based on the proposed numerical model. A variation of porosity of the medium is considered. The generalized non-Darcian model developed takes into account of the presence of a solid drag and the inertial effect. The transient Maxwell’s equations are solved by using the finite difference time domain (FDTD) method to describe the electromagnetic field in the wave guide and medium. The temperature profile and velocity field within a medium are determined by the solution of the momentum, energy and Maxwell’s equations. The coupled non-linear set of these equations are solved using the SIMPLE algorithm. In this work, a detailed parametric study is conducted for a heat transport inside a rectangular enclosure filled with saturated porous medium of constant or variable porosity. The numerical results agree well with the experimental data. Variations in porosity significantly affect the microwave heating process as well as convective flow pattern.
During the last decades a large effort has been invested in the development of a new
discipline devoted to benefit from optical excitations in materials where metals are
key element (Plasmonics). We will make an introduction on this topic below, but let’s
anticipate that two application areas are sensing and information technologies.
The following height extended abstracts, presented during the one-day NANOMAGMA
Symposium (Bilbao, Spain – April 13, 2011 reflects some of the latest developments on magneto-plasmonics.
In 2010 and 2011, the nanoICT project (EU/ICT/FET Coordination Action) launched
two calls for exchange visits for PhD students with the following main objectives: 1.
To perform joint work or to be trained in the leading European industrial and academic research institutions; 2. To enhance long-term collaborations within the ERA; 3. To
generate high-skilled personnel and to facilitate technology transfer;
The first outcome report was published in the issue 22 (August 2011) and this edition
contains four new articles providing insights in relevant fi elds for nanoICT.
We would like to thank all the authors who contributed to this issue as well as the European Commission for the financial support (projects nanoICT No. 216165 and NANOMAGMA No. FP7-214107-2).
Dr. Antonio Correia Editor - Phantoms Foundation
Interior Heating of Rocky Exoplanets from Stellar Flares with Application to ...Sérgio Sacani
Many stars of different spectral types with planets in the habitable zone are known to emit flares. Until now, studies
that address the long-term impact of stellar flares and associated coronal mass ejections (CMEs) assumed that the
planet’s interior remains unaffected by interplanetary CMEs, only considering the effect of plasma/UV
interactions on the atmosphere of planets. Here, we show that the magnetic flux carried by flare-associated CMEs
results in planetary interior heating by ohmic dissipation and leads to a variety of interior–exterior interactions. We
construct a physical model to study this effect and apply it to the TRAPPIST-1 star whose flaring activity has been
constrained by Kepler observations. Our model is posed in a stochastic manner to account for uncertainty and
variability in input parameters. Particularly for the innermost planets, our results suggest that the heat dissipated in
the silicate mantle is both of sufficient magnitude and longevity to drive geological processes and hence facilitate
volcanism and outgassing of the TRAPPIST-1 planets. Furthermore, our model predicts that Joule heating can
further be enhanced for planets with an intrinsic magnetic field compared to those without. The associated
volcanism and outgassing may continuously replenish the atmosphere and thereby mitigate the erosion of the
atmosphere caused by the direct impact of flares and CMEs. To maintain consistency of atmospheric and
geophysical models, the impact of stellar flares and CMEs on atmospheres of close-in exoplanetary systems needs
to be studied in conjunction with the effect on planetary interiors.
magnetic fluid generator, manuscript prepared for 2nd GCMEA 2012 Hilton Longbeach USA. selected one of publish planning presentation abstracts. (already published in a proceedings)
Hysteresis Loops for Magnetoelectric Multiferroics Using Landau-Khalatnikov T...IJECEIAES
We present a theoretical discussion of the hysteresis in magnetoelectric multiferroics with bi-quadratic magnetoelectric coupling. The calculations were performed by employing Landau-Khalatnikov equation of motion for both the ferroelectric and ferromagnetic phase, then solve it simultaneously. In magnetoelectric, we obtain four types of hysteresis: ferroelectric hysteresis, ferromagnetic hysteresis and two types of cross hysteresis (electric field versus magnetization and magnetic field versus electric polarization). The cross hysteresis has butterfly shape which agree with the result from the previous research. It can also be seen from that hysteresis, that magnetization / electric polarization can not be flipped into the opposite direction using external electric / magnetic field when the magnetoelectric coupling is bi-quadratic type. Overall, the result shows that LandauKhalatnikov equation is able to approximate hysteresis loops in multiferroics system.
Hysteresis Loops for Magnetoelectric Multiferroics Using Landau-Khalatnikov T...
Maniotis-XXXII_ABSTRACT
1. XXXII Panhellenic Conference on Solid State Physics and Materials Science
Conference Center "Carolos Papoulias", 18-21 September 2016, Ioannina, Greece
Topic preference (1-6): 3
Presentation preference (oral/poster): poster
Full name of presenting author: Nikolaos Maniotis
e-mail of presenting author: nimaniot@physics.auth.gr
Numerical simulations of interactions between magnetic nanoparticles and living
matter through magnetothermal and magnetomechanical experimental setups
N. Maniotis, A. Makridis, E. Myrovali, T. Samaras and M. Angelakeris
Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
In this work we quantify numerically the interactions between magnetic nanoparticles (MNPs) and the living
matter which take place under varying external magnetic fields and frequencies through two different
procedures: The MNPs magnetic energy density transformation (i) into mechanical forces and (ii) into heat.
For the first case magnetic field gradients are induced by permanent magnets which are placed on a 3D
polymer disk and in close proximity to seeded cells (above the magnets in Fig1a). With COMSOL 3.5a
Multiphysics we estimate the mechanical forces exerted on different lines of cancer cells by cell-internalized
MNPs. Those forces are generated by high-gradient magnetic fields (Fig.1d) and dictate MNPs movements
within the cellular environment. Mechanical stress mediated by localized nanoparticles in HT.29 (human
colorectal adenocarcinoma) and CT 26 cells leads to a significant decrease of cells viability. On the other
hand in magnetic hyperthermia (Figs 1b, 1c) the combination of alternating magnetic fields and magnetic
nanoparticles allows one to cause apoptosis via heat induction. We simulate the heating process of a single
MNP inserted in a biological tissue under an external applied magnetic field. The thermal response of MNPs
with different morphological features is analysed. The results demonstrate the impact of nanoparticle shape
and surface coating in temperature dissipation in and around the nanoparticle. Finally we model the
experimental setup of magnetic hyperthermia for in – vitro experiments. The simulations are repeated for
both experimental setups of the laboratory, one consisting of two circular coils and one of eight squared coils
surrounding the solution (Figs 1e, 1f). COMSOL can easily extend convectional models for one type of
physics into multiphysics models that solve coupled physics phenomena simultaneously and so the electrical
and the thermal problem were solved, calculating the magnetic field and the temperature of the coil and the
solution respectively.
(a)
(b) (c)
(d) (e) (f)
Figure 1: From theory to experiment and vice versa: Magnetic flux density mapping of a permanent NdFeB magnet
placed in the centre of the 3D polymer magnetomechanical disk (1a,1d), Magnetic field distribution generated by two
circular coils (1b,1e) and temperature distribution in the eight squared coils (1c,1f).