2021 IEEE International Workshop on Metrology for Agriculture and Forestry (MetroAgriFor), 2021
This paper presents a comparison of different methodologies for monitoring the plants growth in a... more This paper presents a comparison of different methodologies for monitoring the plants growth in a greenhouse. A 2D measurement based on Computer Vision algorithms and 3D shape measurements techniques (Structured light, LIDAR and photogrammetry) are compared. From the joined 2D and 3D data, an analysis was performed considering health plant indicators. The methodologies are compared among each other. The acquired data are then fed into Deep Learning algorithms in order to detect anomalies in plant growth. The final aim is to give an assessment on the image acquisition methodologies, selecting the most suitable to be used to create the Deep Learning model inputs saving time and resources.
Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2019
We study elastic shear waves of small but finite amplitude, composed of an anti-plane shear motio... more We study elastic shear waves of small but finite amplitude, composed of an anti-plane shear motion and a general in-plane motion. We use a multiple scales expansion to derive an asymptotic system of coupled nonlinear equations describing their propagation in all isotropic incompressible nonlinear elastic solids, generalizing the scalar Zabolotskaya equation of compressible nonlinear elasticity. We show that for a general isotropic incompressible solid, the coupling between anti-plane and in-plane motions cannot be undone and thus conclude that linear polarization is impossible for general nonlinear two-dimensional shear waves. We then use the equations to study the evolution of a nonlinear Gaussian beam in a soft solid: we show that a pure (linearly polarized) shear beam source generates only odd harmonics, but that introducing a slight in-plane noise in the source signal leads to a second harmonic, of the same magnitude as the fifth harmonic, a phenomenon recently observed experime...
Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2019
We study the propagation of linearly polarized transverse waves in a pre-strained incompressible ... more We study the propagation of linearly polarized transverse waves in a pre-strained incompressible isotropic elastic solid. Both finite and small-but-finite amplitude waves are examined. Irrespective of the magnitude of the wave amplitude, these waves may propagate only if the (unit) normal to the plane spanned by the directions of propagation and polarization is a principal direction of the left Cauchy–Green deformation tensor associated with the pre-strained state. A rigorous asymptotic analysis of the equations governing the propagation of waves of small but finite amplitude reveals that the time scale over which the nonlinear effects become significant depends on the direction along which the wave travels. Moreover, we design theoretically an experimental procedure to determine the Landau constants of the fourth-order weakly nonlinear theory of elasticity.
The analytic response for the Cauchy extra stress in large amplitude oscillatory shear (LAOS) is ... more The analytic response for the Cauchy extra stress in large amplitude oscillatory shear (LAOS) is computed from a constitutive model for isotropic incompressible materials, including viscoelastic contributions, and relaxation time. Three cases of frame invariant derivatives are considered: lower, upper, and Jaumann. In the first two cases, the shear stress at steady-state includes the first and third harmonics, and the difference of normal stresses includes the zeroth, second, and fourth harmonics. In the Jaumann case, the stress components are obtained in integral form and are approximated with a Fourier series. The behavior of the coefficients is studied parametrically, as a function of relaxation time and constitutive parameters. Further, the shear stress and the difference of normal stresses are studied as functions of shear strain and shear rate, and are visualized by means of the elastic and viscous Lissajous–Bowditch (LB) plots. Sample results in the Pipkin plane are reported,...
International Journal of Engineering Science, 2016
Abstract In this paper we consider the structure of the symmetry group of some important mechanic... more Abstract In this paper we consider the structure of the symmetry group of some important mechanical theories (nonlinear elasticity and fluids of grade n ). We discuss why the invariance with respect to some well-known transformations must be used with care and we explain why some of these universal transformations are useless to obtain invariant solutions of physical significance.
ABSTRACT A simple model for history dependent nonlinear viscoelasticity is considered. The determ... more ABSTRACT A simple model for history dependent nonlinear viscoelasticity is considered. The determining equation governing shear motions is derived and investigated in the quasistatic approximation and under the traveling waves ansatz. Traveling waves are possible only if an inequality involving the constitutive parameters is satisfied. This fact is in contrast to what happens in viscoelasticity of the Kelvin-Voigt type. On the other hand, in the quasi-static approximation (classical creep and recovery experiments) the behavior of the history dependent model is similar to analogous rate dependent models.
We consider the strain energy recently proposed, on a phenomenological basis by Alan Gent to take... more We consider the strain energy recently proposed, on a phenomenological basis by Alan Gent to take into account limiting chain extensibility in rubber-like materials. We show that this model gives the simplest rational approximation for the reduced tensile force associated with uniaxial extension that satisfies the usual basic assumptions of continuum mechanics. Then by examination of the classical Treloar data on uniaxial extension of rubber, we explain why the Gent model cannot give good predictions for small and moderate strains. We propose some modifications and find a particular one which is able with a minimum number of phenomenological coefficients to give a very good fit to uniaxial data over the full range of deformations.
International Journal of Non-Linear Mechanics, 1989
Abstract An analysis of the propagation of acceleration waves is performed for a solid-gas flow i... more Abstract An analysis of the propagation of acceleration waves is performed for a solid-gas flow in adiabatic or isothermal cases. The flow considered is defined by linear constitutive laws in the condition of phase separation.
International Journal of Non-Linear Mechanics, 1999
ABSTRACT The problem of universal motions of a uniform and isotropic simple material subject to a... more ABSTRACT The problem of universal motions of a uniform and isotropic simple material subject to a generic isotropic internal constraint is studied. Complete results are achieved for motions with space-dependent strain invariants. As an application, free oscillations of an elastic Bell-constrained spherical shell are investigated.
Modern Group Analysis: Advanced Analytical and Computational Methods in Mathematical Physics, 1993
ABSTRACT The characterization of potential systems derived from first order conservation laws and... more ABSTRACT The characterization of potential systems derived from first order conservation laws and of the related potential symmetries is carried out for the Fokker-Planck equation u t =u xx +(a(x)u) x . The potential symmetries for the natural potential system are classified. Via a generalization of the classical reduction method, we obtain classes of exact solutions which contain invariant solutions as a particular case.
2021 IEEE International Workshop on Metrology for Agriculture and Forestry (MetroAgriFor), 2021
This paper presents a comparison of different methodologies for monitoring the plants growth in a... more This paper presents a comparison of different methodologies for monitoring the plants growth in a greenhouse. A 2D measurement based on Computer Vision algorithms and 3D shape measurements techniques (Structured light, LIDAR and photogrammetry) are compared. From the joined 2D and 3D data, an analysis was performed considering health plant indicators. The methodologies are compared among each other. The acquired data are then fed into Deep Learning algorithms in order to detect anomalies in plant growth. The final aim is to give an assessment on the image acquisition methodologies, selecting the most suitable to be used to create the Deep Learning model inputs saving time and resources.
Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2019
We study elastic shear waves of small but finite amplitude, composed of an anti-plane shear motio... more We study elastic shear waves of small but finite amplitude, composed of an anti-plane shear motion and a general in-plane motion. We use a multiple scales expansion to derive an asymptotic system of coupled nonlinear equations describing their propagation in all isotropic incompressible nonlinear elastic solids, generalizing the scalar Zabolotskaya equation of compressible nonlinear elasticity. We show that for a general isotropic incompressible solid, the coupling between anti-plane and in-plane motions cannot be undone and thus conclude that linear polarization is impossible for general nonlinear two-dimensional shear waves. We then use the equations to study the evolution of a nonlinear Gaussian beam in a soft solid: we show that a pure (linearly polarized) shear beam source generates only odd harmonics, but that introducing a slight in-plane noise in the source signal leads to a second harmonic, of the same magnitude as the fifth harmonic, a phenomenon recently observed experime...
Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2019
We study the propagation of linearly polarized transverse waves in a pre-strained incompressible ... more We study the propagation of linearly polarized transverse waves in a pre-strained incompressible isotropic elastic solid. Both finite and small-but-finite amplitude waves are examined. Irrespective of the magnitude of the wave amplitude, these waves may propagate only if the (unit) normal to the plane spanned by the directions of propagation and polarization is a principal direction of the left Cauchy–Green deformation tensor associated with the pre-strained state. A rigorous asymptotic analysis of the equations governing the propagation of waves of small but finite amplitude reveals that the time scale over which the nonlinear effects become significant depends on the direction along which the wave travels. Moreover, we design theoretically an experimental procedure to determine the Landau constants of the fourth-order weakly nonlinear theory of elasticity.
The analytic response for the Cauchy extra stress in large amplitude oscillatory shear (LAOS) is ... more The analytic response for the Cauchy extra stress in large amplitude oscillatory shear (LAOS) is computed from a constitutive model for isotropic incompressible materials, including viscoelastic contributions, and relaxation time. Three cases of frame invariant derivatives are considered: lower, upper, and Jaumann. In the first two cases, the shear stress at steady-state includes the first and third harmonics, and the difference of normal stresses includes the zeroth, second, and fourth harmonics. In the Jaumann case, the stress components are obtained in integral form and are approximated with a Fourier series. The behavior of the coefficients is studied parametrically, as a function of relaxation time and constitutive parameters. Further, the shear stress and the difference of normal stresses are studied as functions of shear strain and shear rate, and are visualized by means of the elastic and viscous Lissajous–Bowditch (LB) plots. Sample results in the Pipkin plane are reported,...
International Journal of Engineering Science, 2016
Abstract In this paper we consider the structure of the symmetry group of some important mechanic... more Abstract In this paper we consider the structure of the symmetry group of some important mechanical theories (nonlinear elasticity and fluids of grade n ). We discuss why the invariance with respect to some well-known transformations must be used with care and we explain why some of these universal transformations are useless to obtain invariant solutions of physical significance.
ABSTRACT A simple model for history dependent nonlinear viscoelasticity is considered. The determ... more ABSTRACT A simple model for history dependent nonlinear viscoelasticity is considered. The determining equation governing shear motions is derived and investigated in the quasistatic approximation and under the traveling waves ansatz. Traveling waves are possible only if an inequality involving the constitutive parameters is satisfied. This fact is in contrast to what happens in viscoelasticity of the Kelvin-Voigt type. On the other hand, in the quasi-static approximation (classical creep and recovery experiments) the behavior of the history dependent model is similar to analogous rate dependent models.
We consider the strain energy recently proposed, on a phenomenological basis by Alan Gent to take... more We consider the strain energy recently proposed, on a phenomenological basis by Alan Gent to take into account limiting chain extensibility in rubber-like materials. We show that this model gives the simplest rational approximation for the reduced tensile force associated with uniaxial extension that satisfies the usual basic assumptions of continuum mechanics. Then by examination of the classical Treloar data on uniaxial extension of rubber, we explain why the Gent model cannot give good predictions for small and moderate strains. We propose some modifications and find a particular one which is able with a minimum number of phenomenological coefficients to give a very good fit to uniaxial data over the full range of deformations.
International Journal of Non-Linear Mechanics, 1989
Abstract An analysis of the propagation of acceleration waves is performed for a solid-gas flow i... more Abstract An analysis of the propagation of acceleration waves is performed for a solid-gas flow in adiabatic or isothermal cases. The flow considered is defined by linear constitutive laws in the condition of phase separation.
International Journal of Non-Linear Mechanics, 1999
ABSTRACT The problem of universal motions of a uniform and isotropic simple material subject to a... more ABSTRACT The problem of universal motions of a uniform and isotropic simple material subject to a generic isotropic internal constraint is studied. Complete results are achieved for motions with space-dependent strain invariants. As an application, free oscillations of an elastic Bell-constrained spherical shell are investigated.
Modern Group Analysis: Advanced Analytical and Computational Methods in Mathematical Physics, 1993
ABSTRACT The characterization of potential systems derived from first order conservation laws and... more ABSTRACT The characterization of potential systems derived from first order conservation laws and of the related potential symmetries is carried out for the Fokker-Planck equation u t =u xx +(a(x)u) x . The potential symmetries for the natural potential system are classified. Via a generalization of the classical reduction method, we obtain classes of exact solutions which contain invariant solutions as a particular case.
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Papers by Edvige Pucci