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Papers by Carlo Andrea Gonano

The cross product frequently occurs in Physics and Engineering, since it has large applications i... more The cross product frequently occurs in Physics and Engineering, since it has large applications in many contexts, e.g. for calculating angular momenta, torques, rotations, volumes etc. Though this mathematical operator is widely used, it is commonly expressed in a 3-D notation which gives rise to many paradoxes and difficulties. In fact, instead of other vector operators like scalar product, the cross product is defined just in 3-D space, it does not respect reflection rules and invokes the concept of "handedness". In this paper we are going to present an extension of cross product in an arbitrary number N of spatial Dimensions, different from the one adopted in the Exterior Algebra and explicitly designed for an easy calculus of moments.

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

Abstract Detectors based on compound semiconductor materials like CdTe and CdZnTe are more suscep... more Abstract Detectors based on compound semiconductor materials like CdTe and CdZnTe are more susceptible to defect-related spectral distortions than elemental semiconductors like Si or Ge. During the design process of new detectors based on these materials it is crucial to consider the effect of these distortions on the detector performance. Due to the diverse range of application areas in which these detectors may be used, the detector geometry must be selected to match the desired application of the device. For those requiring the detection of photons across a broad energy range (1 – 1000 keV), the detector design must account for a variety of different interaction processes. The simulation framework presented in this paper includes all the physical processes involved in the formation of the detector signal, from the radiation absorption mechanisms to the influence of the electrode geometry. A simulation system based on first principle calculations is used which consists of a Monte Carlo simulator, a Finite Elements Method (FEM) calculator and numerical computation software. The framework simulates the radiation–semiconductor interaction, the charge carrier transport and the role of the electric field and weighting field in signal induction on the electrodes. This tool allows to simulate the entire experimental arrangement including the use of attenuators, collimators and scattering surfaces. The ability to accurately simulate the detector response to radiation and its surroundings provides a powerful tool for the realization of a new generation of detector systems. In order to validate the simulation framework, CdZnTe-based detectors with several contact geometries have been modelled and the output of the simulations have been compared to experimental data. A comparison between the simulated and measured responses demonstrate the power of this technique.

ACS applied materials & interfaces, Jan 7, 2018

Gaining access to the cell interior is fundamental for many applications, such as electrical reco... more Gaining access to the cell interior is fundamental for many applications, such as electrical recording, drug and biomolecular delivery. A very promising technique consists of culturing cells on nano/micro pillars. The tight adhesion and high local deformation of cells in contact with nanostructures can promote the permeabilization of lipids at the plasma membrane, providing access to the internal compartment. However, there is still much experimental controversy regarding when and how the intracellular environment is targeted and the role of the geometry and interactions with surfaces. Consequently, we investigated, by coarse-grained molecular dynamics simulations of the cell membrane, the mechanical properties of the lipid bilayer under high strain and bending conditions. We found out that a high curvature of the lipid bilayer dramatically lowers the traction force necessary to achieve membrane rupture. Afterwards, we experimentally studied the permeabilization rate of cell membran...

Metamaterials are artificial materials, made by microscopic unit cells and projected to exhibit s... more Metamaterials are artificial materials, made by microscopic unit cells and projected to exhibit specific macroscopic properties, e.g. they can be designed in order to show a negative refractive index or a superluminal wave propagation. During the last decade, the interest in electromagnetic
metamaterials has been grown because of their possible applications, such as for antennas, transmission lines, lenses, cloaking devices etcetera. In this work we deal specially with metasurfaces, i.e. thin artificial screens or "2D metamaterials". In particular, we analyze how to express the
Huygens' Principle and the Boundary Conditions using the ElectroMagnetic Potentials, also considering the relativistic case. Starting from the Boundary Conditions we derive a circuit model for the project of a screen whose permittivity varepsilon\varepsilonvarepsilon and permeability mu\mumu are assigned. In the last chapters we wonder about the possibility of using metasurfaces in order to realize a holographic television or a hypothetical invisibility cloak.

Dealing with the project of metamaterials scientists often have to design circuit elements at a s... more Dealing with the project of metamaterials scientists often have to design circuit elements at a sub-wavelength (or “microscopic”) scale. At that scale, they use the set of Maxwell’s equations in free-space, and neither permittivity ε nor permeability μ are formally defined. However, the objective is to use the unit cells in order to build a bulk material with some desired “macroscopic” properties. At that scale the set of Maxwell’s equations in matter is adopted. To pass from one approach to the other is not obvious. In this paper we analyse the classic definitions of polarization P and magnetization M, highlighting their limits. Then we propose a definition for P and M fully consistent with Maxwell’s
equations at any scale.

The aim of this work is to introduce an effective tool in order to help the EM designer to select... more The aim of this work is to introduce an effective tool in order to help the EM designer to select the best optimization algorithm through an easy-to-manage classification of Evolutionary Algorithms. In fact, choosing the best tool for an application could be really di cult, especially for a user not aware of optimization theory. Here we propose a general analysis for EAs, highlighting their block-structure and classifying them through some objective (non-qualitative) parameters.

In this paper we examine the possibility to write the circuit equivalent for each of Maxwell's Eq... more In this paper we examine the possibility to write the circuit equivalent for each of Maxwell's Equations in free-space. That could be considered a paradox, since in “empty” space there should be neither currents nor charges. Moreover, in Circuit Theory the space is not continuous but it's a discrete network, made of nodes and edges, and the electric field E→ is approximated as conservative. Here we are going to solve some of those difficulties describing the vector potential A→ as a current iA. In particular we focus the attention on the circuit elements corresponding to Faraday's Law and Lorentz's Gauge.

Circuit models are often used to describe a system in a simply way, lumping its properties in few... more Circuit models are often used to describe a system in a simply way, lumping its properties in few variables and allowing to solve ElectroMagnetic (EM) problems without the need to deal with the complete set of Maxwell's equations. Even if circuit theory is a powerful design tool it has some drawbacks, since the electric field E→ is approximated as conservative and thus the propagation of Transverse EM waves is neglected. However, in this paper we present a circuit model suitably designed to describe also those propagation effects. For sake of simplicity, we consider the problem of the two radiating infinite parallel wires and introduce the concept of “impedance coupling” in order to treat transverse waves. Since EM fields propagate in “empty” space, we are going to interpret the potential vector A→ as a current iA flowing in circuit elements.

The cross product frequently occurs in Physics and Engineering, since it has large applications i... more The cross product frequently occurs in Physics and Engineering, since it has large applications in many contexts, e.g. for calculating angular momenta, torques, rotations, volumes etc. Though this mathematical operator is widely used, it is commonly expressed in a 3-D notation which gives rise to many paradoxes and difficulties. In fact, instead of other vector operators like scalar product, the cross product is defined just in 3-D space, it does not respect reflection rules and invokes the concept of "handedness". In this paper we are going to present an extension of cross product in an arbitrary number N of spatial Dimensions, different from the one adopted in the Exterior Algebra and explicitly designed for an easy calculus of moments.

The cross product frequently occurs in Physics and Engineering, since it has large applications i... more The cross product frequently occurs in Physics and Engineering, since it has large applications in many contexts, e.g. for calculating angular momenta, torques, rotations, volumes etc. Though this mathematical operator is widely used, it is commonly expressed in a 3-D notation which gives rise to many paradoxes and difficulties. In fact, instead of other vector operators like scalar product, the cross product is defined just in 3-D space, it does not respect reflection rules and invokes the concept of "handedness". In this paper we are going to present an extension of cross product in an arbitrary number N of spatial Dimensions, different from the one adopted in the Exterior Algebra and explicitly designed for an easy calculus of moments.

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

Abstract Detectors based on compound semiconductor materials like CdTe and CdZnTe are more suscep... more Abstract Detectors based on compound semiconductor materials like CdTe and CdZnTe are more susceptible to defect-related spectral distortions than elemental semiconductors like Si or Ge. During the design process of new detectors based on these materials it is crucial to consider the effect of these distortions on the detector performance. Due to the diverse range of application areas in which these detectors may be used, the detector geometry must be selected to match the desired application of the device. For those requiring the detection of photons across a broad energy range (1 – 1000 keV), the detector design must account for a variety of different interaction processes. The simulation framework presented in this paper includes all the physical processes involved in the formation of the detector signal, from the radiation absorption mechanisms to the influence of the electrode geometry. A simulation system based on first principle calculations is used which consists of a Monte Carlo simulator, a Finite Elements Method (FEM) calculator and numerical computation software. The framework simulates the radiation–semiconductor interaction, the charge carrier transport and the role of the electric field and weighting field in signal induction on the electrodes. This tool allows to simulate the entire experimental arrangement including the use of attenuators, collimators and scattering surfaces. The ability to accurately simulate the detector response to radiation and its surroundings provides a powerful tool for the realization of a new generation of detector systems. In order to validate the simulation framework, CdZnTe-based detectors with several contact geometries have been modelled and the output of the simulations have been compared to experimental data. A comparison between the simulated and measured responses demonstrate the power of this technique.

ACS applied materials & interfaces, Jan 7, 2018

Gaining access to the cell interior is fundamental for many applications, such as electrical reco... more Gaining access to the cell interior is fundamental for many applications, such as electrical recording, drug and biomolecular delivery. A very promising technique consists of culturing cells on nano/micro pillars. The tight adhesion and high local deformation of cells in contact with nanostructures can promote the permeabilization of lipids at the plasma membrane, providing access to the internal compartment. However, there is still much experimental controversy regarding when and how the intracellular environment is targeted and the role of the geometry and interactions with surfaces. Consequently, we investigated, by coarse-grained molecular dynamics simulations of the cell membrane, the mechanical properties of the lipid bilayer under high strain and bending conditions. We found out that a high curvature of the lipid bilayer dramatically lowers the traction force necessary to achieve membrane rupture. Afterwards, we experimentally studied the permeabilization rate of cell membran...

Metamaterials are artificial materials, made by microscopic unit cells and projected to exhibit s... more Metamaterials are artificial materials, made by microscopic unit cells and projected to exhibit specific macroscopic properties, e.g. they can be designed in order to show a negative refractive index or a superluminal wave propagation. During the last decade, the interest in electromagnetic
metamaterials has been grown because of their possible applications, such as for antennas, transmission lines, lenses, cloaking devices etcetera. In this work we deal specially with metasurfaces, i.e. thin artificial screens or "2D metamaterials". In particular, we analyze how to express the
Huygens' Principle and the Boundary Conditions using the ElectroMagnetic Potentials, also considering the relativistic case. Starting from the Boundary Conditions we derive a circuit model for the project of a screen whose permittivity varepsilon\varepsilonvarepsilon and permeability mu\mumu are assigned. In the last chapters we wonder about the possibility of using metasurfaces in order to realize a holographic television or a hypothetical invisibility cloak.

Dealing with the project of metamaterials scientists often have to design circuit elements at a s... more Dealing with the project of metamaterials scientists often have to design circuit elements at a sub-wavelength (or “microscopic”) scale. At that scale, they use the set of Maxwell’s equations in free-space, and neither permittivity ε nor permeability μ are formally defined. However, the objective is to use the unit cells in order to build a bulk material with some desired “macroscopic” properties. At that scale the set of Maxwell’s equations in matter is adopted. To pass from one approach to the other is not obvious. In this paper we analyse the classic definitions of polarization P and magnetization M, highlighting their limits. Then we propose a definition for P and M fully consistent with Maxwell’s
equations at any scale.

The aim of this work is to introduce an effective tool in order to help the EM designer to select... more The aim of this work is to introduce an effective tool in order to help the EM designer to select the best optimization algorithm through an easy-to-manage classification of Evolutionary Algorithms. In fact, choosing the best tool for an application could be really di cult, especially for a user not aware of optimization theory. Here we propose a general analysis for EAs, highlighting their block-structure and classifying them through some objective (non-qualitative) parameters.

In this paper we examine the possibility to write the circuit equivalent for each of Maxwell's Eq... more In this paper we examine the possibility to write the circuit equivalent for each of Maxwell's Equations in free-space. That could be considered a paradox, since in “empty” space there should be neither currents nor charges. Moreover, in Circuit Theory the space is not continuous but it's a discrete network, made of nodes and edges, and the electric field E→ is approximated as conservative. Here we are going to solve some of those difficulties describing the vector potential A→ as a current iA. In particular we focus the attention on the circuit elements corresponding to Faraday's Law and Lorentz's Gauge.

Circuit models are often used to describe a system in a simply way, lumping its properties in few... more Circuit models are often used to describe a system in a simply way, lumping its properties in few variables and allowing to solve ElectroMagnetic (EM) problems without the need to deal with the complete set of Maxwell's equations. Even if circuit theory is a powerful design tool it has some drawbacks, since the electric field E→ is approximated as conservative and thus the propagation of Transverse EM waves is neglected. However, in this paper we present a circuit model suitably designed to describe also those propagation effects. For sake of simplicity, we consider the problem of the two radiating infinite parallel wires and introduce the concept of “impedance coupling” in order to treat transverse waves. Since EM fields propagate in “empty” space, we are going to interpret the potential vector A→ as a current iA flowing in circuit elements.

The cross product frequently occurs in Physics and Engineering, since it has large applications i... more The cross product frequently occurs in Physics and Engineering, since it has large applications in many contexts, e.g. for calculating angular momenta, torques, rotations, volumes etc. Though this mathematical operator is widely used, it is commonly expressed in a 3-D notation which gives rise to many paradoxes and difficulties. In fact, instead of other vector operators like scalar product, the cross product is defined just in 3-D space, it does not respect reflection rules and invokes the concept of "handedness". In this paper we are going to present an extension of cross product in an arbitrary number N of spatial Dimensions, different from the one adopted in the Exterior Algebra and explicitly designed for an easy calculus of moments.

Metamaterials are artificial materials, made by microscopic unit cells and projected to exhibit s... more Metamaterials are artificial materials, made by microscopic unit cells and projected to exhibit specific macroscopic properties, e.g. they can be designed in order to show a negative refractive index or a superluminal wave propagation. During the last decade, the interest in electromagnetic
metamaterials has been grown because of their possible applications, such as for antennas, transmission lines, lenses, cloaking devices etcetera. In this work we deal specially with metasurfaces, i.e. thin artificial screens or "2D metamaterials". In particular, we analyze how to express the
Huygens' Principle and the Boundary Conditions using the ElectroMagnetic Potentials, also considering the relativistic case. Starting from the Boundary Conditions we derive a circuit model for the project of a screen whose permittivity varepsilon\varepsilonvarepsilon and permeability mu\mumu are assigned. In the last chapters we wonder about the possibility of using metasurfaces in order to realize a holographic television or a hypothetical invisibility cloak.