Iberian Meeting on Computational Electromagnetics (EIEC)
http://hdl.handle.net/2117/369300
2024-10-08T12:56:12ZNumerical modelling of oocytes partially covered by magnetic nanoparticles in external magnetic fields
http://hdl.handle.net/2117/369914
Numerical modelling of oocytes partially covered by magnetic nanoparticles in external magnetic fields
Molina-Cuberos, Gregorio J.; García-Collado, Ángel J.; García Vázquez, Francisco A.; Jiménez Movilla, María
Nanorep® is a novel device based on the magnetic tweezer concept that has been
developed for precise, fast, and non-aggressive oocytes and embryos manipulation. To
operate the reproductive cells, they are first immersed in a standard host medium with
ferrite containing nanoparticles. The magnetic particles are attached to the external
matrix of the oocytes/embryos thanks to a linked protein making possible to control
them by using external magnetic fields. Electron microscope photographs show
magnetic particle aggregates around the oocyte. The total mass and distribution of the
attached magnetic particles per oocyte show a wide range of variability, which strongly
affects their magnetic response. Despite the uncertainties on the attachment of
magnetic nanoparticles, the set formed by the oocyte and the nanoparticles can be
caught and transported by using standard neodymium magnets.
Here we present an initial study of the interaction between the set
oocyte/nanoparticles and the external magnetic field in aqueous environment. We are
going to discuss several relevant topics of the model such us the characterization of
magnetic field produced by cylindrical neodymium magnets, the model of the ferrite
magnetization as an effective spherical dipole or a magnetized spherical shell, the
measurement processes to obtain the temporal evolution of the particle position and
the different observed dynamic behaviours.
2022-07-08T14:39:33ZMolina-Cuberos, Gregorio J.García-Collado, Ángel J.García Vázquez, Francisco A.Jiménez Movilla, MaríaNanorep® is a novel device based on the magnetic tweezer concept that has been
developed for precise, fast, and non-aggressive oocytes and embryos manipulation. To
operate the reproductive cells, they are first immersed in a standard host medium with
ferrite containing nanoparticles. The magnetic particles are attached to the external
matrix of the oocytes/embryos thanks to a linked protein making possible to control
them by using external magnetic fields. Electron microscope photographs show
magnetic particle aggregates around the oocyte. The total mass and distribution of the
attached magnetic particles per oocyte show a wide range of variability, which strongly
affects their magnetic response. Despite the uncertainties on the attachment of
magnetic nanoparticles, the set formed by the oocyte and the nanoparticles can be
caught and transported by using standard neodymium magnets.
Here we present an initial study of the interaction between the set
oocyte/nanoparticles and the external magnetic field in aqueous environment. We are
going to discuss several relevant topics of the model such us the characterization of
magnetic field produced by cylindrical neodymium magnets, the model of the ferrite
magnetization as an effective spherical dipole or a magnetized spherical shell, the
measurement processes to obtain the temporal evolution of the particle position and
the different observed dynamic behaviours.Synthetic aperture radar imagery using SOCET GXP®
http://hdl.handle.net/2117/369913
Synthetic aperture radar imagery using SOCET GXP®
Duarte, Afonso M.; Topa, António L.
Synthetic Aperture Radar (SAR) provides high resolution images for a multitude of applications.
The main purpose of this work is to provide the reader to get accustomed to application oriented
SAR data processing and visualization. This goal is achieved using BAE SYSTEMS SOCET GXP®
software tool. The obtained results present a solid approach by using the tool for the exploitation of
SAR images as a source for geospatial information and data regarding water resource detection, terrain
feature extraction, vegetation health assessment among other applications.
2022-07-08T14:35:58ZDuarte, Afonso M.Topa, António L.Synthetic Aperture Radar (SAR) provides high resolution images for a multitude of applications.
The main purpose of this work is to provide the reader to get accustomed to application oriented
SAR data processing and visualization. This goal is achieved using BAE SYSTEMS SOCET GXP®
software tool. The obtained results present a solid approach by using the tool for the exploitation of
SAR images as a source for geospatial information and data regarding water resource detection, terrain
feature extraction, vegetation health assessment among other applications.Signal power variation for bio-radar applications
http://hdl.handle.net/2117/369911
Signal power variation for bio-radar applications
Gouveia, Carolina; Cruz, Beatriz; Pinho, Pedro; Albuquerque, Daniel
Micro-Doppler radars have been widely used for the
remote vital signs acquisition. In those cases, the signals quality is
directly related with the received power provided by the reflecting
chest-wall. In order to determine which is the optimal radar
configuration, it is important to study the signal behavior in the
near-field region considering the Radar Cross Section (RCS) of
the human chest. In this work, simulations are performed to
characterize the received signal power variation, considering the
subject distance in relation to the radar.
2022-07-08T14:25:55ZGouveia, CarolinaCruz, BeatrizPinho, PedroAlbuquerque, DanielMicro-Doppler radars have been widely used for the
remote vital signs acquisition. In those cases, the signals quality is
directly related with the received power provided by the reflecting
chest-wall. In order to determine which is the optimal radar
configuration, it is important to study the signal behavior in the
near-field region considering the Radar Cross Section (RCS) of
the human chest. In this work, simulations are performed to
characterize the received signal power variation, considering the
subject distance in relation to the radar.Relativistic particle motion of a charge including the radiation reaction
http://hdl.handle.net/2117/369847
Relativistic particle motion of a charge including the radiation reaction
Martín-Luna, P.; Esperante, D.; Gimeno, B.; González-Iglesias, D.; Blanch, C.; Fuster-Martínez, N.; Martinez-Reviriego, P.; Fuster, J.
The problem of the electromagnetic radiation of an accelerated charged particle is one of the
most controversial issues in Physics since the beginning of the last century representing one of
the most popular unsolved problems of the Modern Physics. Different equations of motion for
a point charge including the electromagnetic radiation emitted have been proposed throughout
history, but all these expressions show some limitations. An equation based on the principle of
conservation of energy is proposed for the ultra-relativistic motion. Different examples are
analyzed showing that the energy lost by the charge agrees with the relativistic generalization
of the Larmor formula. This proposed equation has been compared with the Landau-Lifshitz
equation obtaining a good agreement in the range of application of the Landau-Lifshitz formula.
Finally, it is discussed a possible variation of the typical relativistic particle integrators (e.g. Boris,
Vay or Higuera-Cary methods) in order to include the radiation reaction.
2022-07-07T18:23:44ZMartín-Luna, P.Esperante, D.Gimeno, B.González-Iglesias, D.Blanch, C.Fuster-Martínez, N.Martinez-Reviriego, P.Fuster, J.The problem of the electromagnetic radiation of an accelerated charged particle is one of the
most controversial issues in Physics since the beginning of the last century representing one of
the most popular unsolved problems of the Modern Physics. Different equations of motion for
a point charge including the electromagnetic radiation emitted have been proposed throughout
history, but all these expressions show some limitations. An equation based on the principle of
conservation of energy is proposed for the ultra-relativistic motion. Different examples are
analyzed showing that the energy lost by the charge agrees with the relativistic generalization
of the Larmor formula. This proposed equation has been compared with the Landau-Lifshitz
equation obtaining a good agreement in the range of application of the Landau-Lifshitz formula.
Finally, it is discussed a possible variation of the typical relativistic particle integrators (e.g. Boris,
Vay or Higuera-Cary methods) in order to include the radiation reaction.A GNU library for high order boudary integral equation methods in electromagnetism
http://hdl.handle.net/2117/369846
A GNU library for high order boudary integral equation methods in electromagnetism
Vico, Felipe
In this talk we will present a GNU library made by The Simons Foundation, Inc
(Leslie Greengard and Manas Racch), Michael O’Neil, Felipe Vico and others.
The library can be downloaded from https://fastalgorithms.github.io/ and consist
of a set of functions for the high order discretization of integral equations in
electromagnetism. We will explain the main functionalities and interfaces available.
The source code is made in fortran and there are wrappers from Matlab,
Python, C and other high order languages. The surface geometry is provided
by using high order triangular patches and the induced densities on the surface
are described by using Koorwninder orthogonal polynomials. The functions
provided allow to compute the field on the surface by using a multilevel fast
multipole algorithm that is stable in low frequency and a fast adaptive quadrature
algorithm for the near interaction terms. The EM formulations provided
are: the decoupled potential integral equation (DPIE), the non-resonant chargecurrent
integral equation (NRCCIE) and the regularized combined source integral
equation (RCSIE). Those formulations are particularly interesting in the
low frequency regime due to its stability but can be also used in higher frequencies.
The library uses openmp for paralelization and explicit SIMD vectorization
for the evaluation of the near field in the adaptive quadrature algorithm. The
resulting algorithms don’t suffer from high density mesh breakdown, instead the
user can obtain arbitrarily low errors by doing hp refinement (reducing the size
of the triangles and increasing the order of the polynomials on each triangle).
The formulations allow also adaptive discretizations for geometries with small
details.
The talk will include a quick user’s guide to the library and interfaces and its
installation process in different platforms. We will also show different numerical
results.
The library also contains low level functions that allow to implement easily
other EM formulations or the use of different basis/test functions easily making
use of all the adaptive integration and FMM machinery.
2022-07-07T17:31:18ZVico, FelipeIn this talk we will present a GNU library made by The Simons Foundation, Inc
(Leslie Greengard and Manas Racch), Michael O’Neil, Felipe Vico and others.
The library can be downloaded from https://fastalgorithms.github.io/ and consist
of a set of functions for the high order discretization of integral equations in
electromagnetism. We will explain the main functionalities and interfaces available.
The source code is made in fortran and there are wrappers from Matlab,
Python, C and other high order languages. The surface geometry is provided
by using high order triangular patches and the induced densities on the surface
are described by using Koorwninder orthogonal polynomials. The functions
provided allow to compute the field on the surface by using a multilevel fast
multipole algorithm that is stable in low frequency and a fast adaptive quadrature
algorithm for the near interaction terms. The EM formulations provided
are: the decoupled potential integral equation (DPIE), the non-resonant chargecurrent
integral equation (NRCCIE) and the regularized combined source integral
equation (RCSIE). Those formulations are particularly interesting in the
low frequency regime due to its stability but can be also used in higher frequencies.
The library uses openmp for paralelization and explicit SIMD vectorization
for the evaluation of the near field in the adaptive quadrature algorithm. The
resulting algorithms don’t suffer from high density mesh breakdown, instead the
user can obtain arbitrarily low errors by doing hp refinement (reducing the size
of the triangles and increasing the order of the polynomials on each triangle).
The formulations allow also adaptive discretizations for geometries with small
details.
The talk will include a quick user’s guide to the library and interfaces and its
installation process in different platforms. We will also show different numerical
results.
The library also contains low level functions that allow to implement easily
other EM formulations or the use of different basis/test functions easily making
use of all the adaptive integration and FMM machinery.Enriched finite element formulation for discontinuous electric field in electrohydrodynamic problems
http://hdl.handle.net/2117/369845
Enriched finite element formulation for discontinuous electric field in electrohydrodynamic problems
Narváez Muñoz, Christian; Hashemi, Mohammad Reza; Ryzhakov, Pavel; Pons Prats, Jordi; Owen, Herbert
Although purely analytical models can provide rough qualitative predictions
in the field of electrohydrodynamics (EHD), more sophisticated numerical
approaches are necessary to quantitatively study the involved phenomena
[1, 2]. Considering the computational cost and complexities associated
with the mesh-free numerical methods, mesh-based methods are usually more
efficient for fluid dynamics applications. Nevertheless, in the case of multiphase
EHD flows, the difference in the material properties of the phases
imposes discontinuities in the field variables (e.g. pressure, electric field).
In this sense, the accuracy of the solution of EHD problems depends on the
sharp representation of the strong (jump) and weak discontinuities in the field
variables. So far, different numerical techniques have been proposed in the
literature to represent such discontinuity, for example, Weighted Harmonic
Averaging Method (WHAM), the Ghost Fluid Method (GFM), Immersed
Interface Method (IIM), to name just a few. However, these schemes can
accurately capture the electric field only in cases of small permittivity ratio,
perfect dielectric fluids, or via a computationally expensive refinement
process. On the other hand, the Enriched Finite Element Method (EFEM)
can be acquired as a viable option for EHD problems. EFEM relies on the enrichment of the shape functions for the elements cut by the phase interface.
In this work, such enrichment is proposed to accurately capture the weak discontinuity
in the electric potential (or equivalently the jump in the electric field), adopting the ideas previously explored for representing pressure gradient
discontinuity in two-phase flows [3]. The main advantage of this method is that the enrichment functions do not depend on the neighboring elements, and therefore, the associated additional degrees of freedom (DoF) can be
condensed at the elemental level. This feature makes EFEM one of the most
efficient techniques for multi-phase problems. Although this technique has
been widely used for multi-phase CFD applications [4, 5], the employment
of EFEM for EHD applications has scarcely been addressed in the literature.
In this sense, the present work is among the very first applications of the
EFEM method to EHD problems.
2022-07-07T17:21:28ZNarváez Muñoz, ChristianHashemi, Mohammad RezaRyzhakov, PavelPons Prats, JordiOwen, HerbertAlthough purely analytical models can provide rough qualitative predictions
in the field of electrohydrodynamics (EHD), more sophisticated numerical
approaches are necessary to quantitatively study the involved phenomena
[1, 2]. Considering the computational cost and complexities associated
with the mesh-free numerical methods, mesh-based methods are usually more
efficient for fluid dynamics applications. Nevertheless, in the case of multiphase
EHD flows, the difference in the material properties of the phases
imposes discontinuities in the field variables (e.g. pressure, electric field).
In this sense, the accuracy of the solution of EHD problems depends on the
sharp representation of the strong (jump) and weak discontinuities in the field
variables. So far, different numerical techniques have been proposed in the
literature to represent such discontinuity, for example, Weighted Harmonic
Averaging Method (WHAM), the Ghost Fluid Method (GFM), Immersed
Interface Method (IIM), to name just a few. However, these schemes can
accurately capture the electric field only in cases of small permittivity ratio,
perfect dielectric fluids, or via a computationally expensive refinement
process. On the other hand, the Enriched Finite Element Method (EFEM)
can be acquired as a viable option for EHD problems. EFEM relies on the enrichment of the shape functions for the elements cut by the phase interface.
In this work, such enrichment is proposed to accurately capture the weak discontinuity
in the electric potential (or equivalently the jump in the electric field), adopting the ideas previously explored for representing pressure gradient
discontinuity in two-phase flows [3]. The main advantage of this method is that the enrichment functions do not depend on the neighboring elements, and therefore, the associated additional degrees of freedom (DoF) can be
condensed at the elemental level. This feature makes EFEM one of the most
efficient techniques for multi-phase problems. Although this technique has
been widely used for multi-phase CFD applications [4, 5], the employment
of EFEM for EHD applications has scarcely been addressed in the literature.
In this sense, the present work is among the very first applications of the
EFEM method to EHD problems.Grid design benchmark on sheets with nonzero thickness
http://hdl.handle.net/2117/369844
Grid design benchmark on sheets with nonzero thickness
Úbeda Farré, Eduard; Rius Casals, Juan Manuel; Heldring, Alexander; López Menchón, Héctor
The conventional scattering analysis of perfectly conducting sheets ignores the scattering
contribution of the rim. The so-called thin-surface scheme arises from the discretization of the
Electric-field Integral Equation by assuming the sheet thickness to be null. This gives rise to many
less unknowns than the full approach, arising from modelling the whole plate. Although good
accuracy is observed in many practical applications, the thin-plate scattering analysis of thick
enough sheets, especially under oblique incidences, with low grazing angles, exhibits great
inaccuracies. A recent approach, so-called thick-surface, has proved to show similar accuracy as the
full scheme, also in those cases where the thin-surface scheme fails, with moderate computational
effort. In this paper, we show RCS results computed with the thick-surface approach for several
sheets with nonzero thickness where the thin-surface scheme fails. Several types of meshes are
adopted, triangular, quadrangular or hybrid. The required symmetries for the generation of the
meshes are pointed out in each case.
2022-07-07T17:16:17ZÚbeda Farré, EduardRius Casals, Juan ManuelHeldring, AlexanderLópez Menchón, HéctorThe conventional scattering analysis of perfectly conducting sheets ignores the scattering
contribution of the rim. The so-called thin-surface scheme arises from the discretization of the
Electric-field Integral Equation by assuming the sheet thickness to be null. This gives rise to many
less unknowns than the full approach, arising from modelling the whole plate. Although good
accuracy is observed in many practical applications, the thin-plate scattering analysis of thick
enough sheets, especially under oblique incidences, with low grazing angles, exhibits great
inaccuracies. A recent approach, so-called thick-surface, has proved to show similar accuracy as the
full scheme, also in those cases where the thin-surface scheme fails, with moderate computational
effort. In this paper, we show RCS results computed with the thick-surface approach for several
sheets with nonzero thickness where the thin-surface scheme fails. Several types of meshes are
adopted, triangular, quadrangular or hybrid. The required symmetries for the generation of the
meshes are pointed out in each case.Numerical study of dark current dynamics in a high-gradient backward travelling wave accelerating cavity using the electromagnetic simulation software CST studio.
http://hdl.handle.net/2117/369843
Numerical study of dark current dynamics in a high-gradient backward travelling wave accelerating cavity using the electromagnetic simulation software CST studio.
Martinez-Reviriego, P.; Esperante, D.; Gimeno, B.; Fuster-Martínez, N.; González-Iglesias, D.; Blanch, C.; Martín-Luna, P.; Fuster, J.
High-Gradient accelerating cavities are one of the main research lines in the development of
compact linear colliders. However, the operation of such cavities is currently limited by nonlinear
effects that are intensified at high electric fields, such as dark currents and radiation
emission or RF breakdowns.
A new normal-conducting High-Gradient S-band Backward Travelling Wave accelerating
cavity for medical application (v=0.38c) designed and constructed at Conseil Européen pour la
Recherche Nucléaire (CERN) is being tested at Instituto de Física Corpuscular (IFIC) High Power
RF Laboratory. The objective consists of studying its viability in the development of compact
linear accelerators for hadrontherapy treatments in hospitals.
Due to the high surface electric field in the cavity, electrons are emitted following Fowler-
Nordheim equation, also known as dark currents. The emission and dynamic of these
electrons are of fundamental importance on different phenomena such as RF Breakdowns or
radiation dose emission.
In this work, 3D electromagnetic numerical simulations have been performed using the
computer simulation technology software CST Studio Suite. Then, the resulting EM field maps
are used to study the emission and electron dynamics inside the cavity. The simulation results
are compared with experimental data and first conclusions discussed.
2022-07-07T17:10:56ZMartinez-Reviriego, P.Esperante, D.Gimeno, B.Fuster-Martínez, N.González-Iglesias, D.Blanch, C.Martín-Luna, P.Fuster, J.High-Gradient accelerating cavities are one of the main research lines in the development of
compact linear colliders. However, the operation of such cavities is currently limited by nonlinear
effects that are intensified at high electric fields, such as dark currents and radiation
emission or RF breakdowns.
A new normal-conducting High-Gradient S-band Backward Travelling Wave accelerating
cavity for medical application (v=0.38c) designed and constructed at Conseil Européen pour la
Recherche Nucléaire (CERN) is being tested at Instituto de Física Corpuscular (IFIC) High Power
RF Laboratory. The objective consists of studying its viability in the development of compact
linear accelerators for hadrontherapy treatments in hospitals.
Due to the high surface electric field in the cavity, electrons are emitted following Fowler-
Nordheim equation, also known as dark currents. The emission and dynamic of these
electrons are of fundamental importance on different phenomena such as RF Breakdowns or
radiation dose emission.
In this work, 3D electromagnetic numerical simulations have been performed using the
computer simulation technology software CST Studio Suite. Then, the resulting EM field maps
are used to study the emission and electron dynamics inside the cavity. The simulation results
are compared with experimental data and first conclusions discussed.Analysis of chiral effects in non-planar metamaterials with oblique incidence
http://hdl.handle.net/2117/369838
Analysis of chiral effects in non-planar metamaterials with oblique incidence
Fernández, Óscar; Ben Jamoun, Jihad; Gómez, Álvaro; Barba, Ismael; Grande, Ana M.; López Cabeceira, Ana C.
One of the main research lines of the Grupo de Electromagnetismo of the Universidad de Cantabria is focused on the
study and characterization of planar chiral metamaterial (CMM) structures implemented on printed circuit board technology.
The objective of this communication is to analyze the influence of the angle of incidence on the chiral behavior
of metamaterial structures. A variation of the split ring resonator (SRR) particle has been used as unit cell of the periodic
metamaterials analyzed.
From this structure, the effect of the angle of incidence on the chiral response is analyzed, evaluating variations in the
geometry that provide different types of interaction between unit cells or between the incident wave and the structure.
The SRRs are printed only on one side of the printed circuit board. Fig.1. This way, with normal incidence the structure
is achiral.
The obtained results show that the angle of incidence is a key parameter for the structure in order to present a chiral
behavior. In this case, the chiral behavior is shown as a high difference between the transmission levels of the two eigenwaves
(left handed and right handed circular polarized waves), i.e., circular dichroism.
2022-07-07T15:57:47ZFernández, ÓscarBen Jamoun, JihadGómez, ÁlvaroBarba, IsmaelGrande, Ana M.López Cabeceira, Ana C.One of the main research lines of the Grupo de Electromagnetismo of the Universidad de Cantabria is focused on the
study and characterization of planar chiral metamaterial (CMM) structures implemented on printed circuit board technology.
The objective of this communication is to analyze the influence of the angle of incidence on the chiral behavior
of metamaterial structures. A variation of the split ring resonator (SRR) particle has been used as unit cell of the periodic
metamaterials analyzed.
From this structure, the effect of the angle of incidence on the chiral response is analyzed, evaluating variations in the
geometry that provide different types of interaction between unit cells or between the incident wave and the structure.
The SRRs are printed only on one side of the printed circuit board. Fig.1. This way, with normal incidence the structure
is achiral.
The obtained results show that the angle of incidence is a key parameter for the structure in order to present a chiral
behavior. In this case, the chiral behavior is shown as a high difference between the transmission levels of the two eigenwaves
(left handed and right handed circular polarized waves), i.e., circular dichroism.Dual band circular polarization selector using asymmetric SRR mirrors
http://hdl.handle.net/2117/369836
Dual band circular polarization selector using asymmetric SRR mirrors
Barba, Ismael; Grande, Ana; López Cabeceira, Ana C.; Fernández, Óscar; Gómez, Álvaro
In this work we aim to design circularly polarized flat mirror/reflectarray to work at a dual frequency. The design approach uses
a unit cell made by four assymetrical split-ring resonators with an opposite rotation plus an element size variation, a seen in Fig.1
Fig. 1. Proposed structure (unit cell). The SRRs are made
on copper on a FR4 substrate. There is a metallic (copper)
plane mirror behind the structure. The inner rings have a
radius of 5.8 mm (1st and 3rd quadrant) and 5mm (2nd and
4th quadrant). The outer rings have a radius of 10.2mm
and 10mm, respectively.
As we may see in Fig.2, the proposed structure presents a dual-band circular polarization selection: in the band around 2.97 GHz
it absorbs LHCP incident waves while reflecting LHCP incident waves, doing the opposite around 3.28 GHz
Fig. 2. Reflection coefficient for a circularly polarized
wave normally incident on a structure as shown in Fig.1.
The superindexes +/- stand for right-handed/left-handed
circular polarized waves.
2022-07-07T15:52:21ZBarba, IsmaelGrande, AnaLópez Cabeceira, Ana C.Fernández, ÓscarGómez, ÁlvaroIn this work we aim to design circularly polarized flat mirror/reflectarray to work at a dual frequency. The design approach uses
a unit cell made by four assymetrical split-ring resonators with an opposite rotation plus an element size variation, a seen in Fig.1
Fig. 1. Proposed structure (unit cell). The SRRs are made
on copper on a FR4 substrate. There is a metallic (copper)
plane mirror behind the structure. The inner rings have a
radius of 5.8 mm (1st and 3rd quadrant) and 5mm (2nd and
4th quadrant). The outer rings have a radius of 10.2mm
and 10mm, respectively.
As we may see in Fig.2, the proposed structure presents a dual-band circular polarization selection: in the band around 2.97 GHz
it absorbs LHCP incident waves while reflecting LHCP incident waves, doing the opposite around 3.28 GHz
Fig. 2. Reflection coefficient for a circularly polarized
wave normally incident on a structure as shown in Fig.1.
The superindexes +/- stand for right-handed/left-handed
circular polarized waves.