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Wed, 21 Feb 2024 13:51:12 GMT
20240221T13:51:12Z

Relation entre l'entropie physique le codage de l'information et l'énergie de simulation
http://hdl.handle.net/10985/10787
Relation entre l'entropie physique le codage de l'information et l'énergie de simulation; Relationship between physical entropy, coding of information and energy simulation
BIGERELLE, Maxence; IOST, Alain
Dans cette note, nous analysons l’entropie de mélange d’un système physique à l’équilibre par la théorie algorithmique de l’information. Nous montrons l’existence d’un isomorphisme entre cette entropie et la taille du programme informatique qui simule ce système physique. Cet isomorphisme doit être construit en respectant certaines règles, et le meilleur résultat est obtenu en combinant les algorithmes de compression RLE « run length encoding » et Huffman. Si le système physique est codé par la composition de ces deux isomorphismes basés sur le dénombrement des séquences identiques puis de leur codage en dictionnaire, nous pouvons quantifier l’entropie de systèmes binaires ou ternaires à l’état d’équilibre. De plus, il existe une relation affine entre l’énergie de simulation du système physique et l’énergie libre du système.; It is shown that an isomorphism exists between the mixing entropy and the size of a computer program that simulates the physical system. This isomorphism must be constructed with respect to some theorems, and it is shown that the composition of two isomorphisms, one based on a run length encoding and another by encoding sequences in a dictionary allows us to quantify the entropy of binary and ternary systems at the equilibrium. Finally, it is shown that the energy consumed by a physical system encoded by this system and executed on a Turing machine is proportional to the free energy of the thermodynamic system.
Mon, 01 Jan 2007 00:00:00 GMT
http://hdl.handle.net/10985/10787
20070101T00:00:00Z
BIGERELLE, Maxence
IOST, Alain
Dans cette note, nous analysons l’entropie de mélange d’un système physique à l’équilibre par la théorie algorithmique de l’information. Nous montrons l’existence d’un isomorphisme entre cette entropie et la taille du programme informatique qui simule ce système physique. Cet isomorphisme doit être construit en respectant certaines règles, et le meilleur résultat est obtenu en combinant les algorithmes de compression RLE « run length encoding » et Huffman. Si le système physique est codé par la composition de ces deux isomorphismes basés sur le dénombrement des séquences identiques puis de leur codage en dictionnaire, nous pouvons quantifier l’entropie de systèmes binaires ou ternaires à l’état d’équilibre. De plus, il existe une relation affine entre l’énergie de simulation du système physique et l’énergie libre du système.
It is shown that an isomorphism exists between the mixing entropy and the size of a computer program that simulates the physical system. This isomorphism must be constructed with respect to some theorems, and it is shown that the composition of two isomorphisms, one based on a run length encoding and another by encoding sequences in a dictionary allows us to quantify the entropy of binary and ternary systems at the equilibrium. Finally, it is shown that the energy consumed by a physical system encoded by this system and executed on a Turing machine is proportional to the free energy of the thermodynamic system.

A new model of the heat transfer in materials: the surfacic potential algorithm
http://hdl.handle.net/10985/9732
A new model of the heat transfer in materials: the surfacic potential algorithm
BIGERELLE, Maxence; BOUNICHANE, Benaamer; HAGEGE, Benjamin; JOURANI, Abdeljalil; IOST, Alain
This paper proposes a new simulation method of thermal transfers based on the concepts of Brownian motion via the theory of potential and the characteristics of materials. In our simulation the particles take their origins on the surface and we propose an algorithm called 'Surfacic Potential Algorithm' that allows to determine the cartography of the temperatures. This algorithm has a better convergence than the one resulting from the potential theory and allows to treat adiabatic surfaces. It also includes the thermal heterogeneity of material. Its relevance is verified on thermal problems whose analytical solution is known.
Fri, 01 Jan 2010 00:00:00 GMT
http://hdl.handle.net/10985/9732
20100101T00:00:00Z
BIGERELLE, Maxence
BOUNICHANE, Benaamer
HAGEGE, Benjamin
JOURANI, Abdeljalil
IOST, Alain
This paper proposes a new simulation method of thermal transfers based on the concepts of Brownian motion via the theory of potential and the characteristics of materials. In our simulation the particles take their origins on the surface and we propose an algorithm called 'Surfacic Potential Algorithm' that allows to determine the cartography of the temperatures. This algorithm has a better convergence than the one resulting from the potential theory and allows to treat adiabatic surfaces. It also includes the thermal heterogeneity of material. Its relevance is verified on thermal problems whose analytical solution is known.

An expert system to characterise the surfaces morphological properties according to their tribological functionalities: The relevance of a pair of roughness parameters
http://hdl.handle.net/10985/9672
An expert system to characterise the surfaces morphological properties according to their tribological functionalities: The relevance of a pair of roughness parameters
BIGERELLE, Maxence; NAJJAR, Denis; MATHIA, Thomas; IOST, Alain; COOREVITS, Thierry; ANSELME, Karine
Knowing that a surface or profile can be characterized by numerous roughness parameters, the objective of this investigation was to present a methodology which aims to determine quantitatively and without preconceived opinion the most relevant pair of roughness parameters that describe an abraded surface. The methodology was firstly validated on simulated fractal profiles having different amplitudes and Hölder exponents and it was secondly applied to characterise different worn regions of a retrieved metallic femoral head articulated against an ultrahigh molecular weight polyethylene (UHMWPE) acetabular cup containing an embedded metallic fibber into its surface. The methodology consists in combining the recent Bootstrap method with the usual discriminant analysis. It was validated on simulated fractal profiles showing that, among more than 3000 pairs tested, the total amplitude Rt and the fractal dimension Δ is the most relevant pair of roughness parameters; parameters corresponding to the variables modulated in the analytical expression of the fractal function. The application of this methodology on a retrieved metallic femoral head shows that the most relevant pair of parameters for discriminating the different investigated worn regions is the arithmetic roughness parameter Ra paired with the mean peak height Rpm. This methodology finally helps in a better understanding of the scratch mechanism of this orthopedic bearing component.
Tue, 01 Jan 2013 00:00:00 GMT
http://hdl.handle.net/10985/9672
20130101T00:00:00Z
BIGERELLE, Maxence
NAJJAR, Denis
MATHIA, Thomas
IOST, Alain
COOREVITS, Thierry
ANSELME, Karine
Knowing that a surface or profile can be characterized by numerous roughness parameters, the objective of this investigation was to present a methodology which aims to determine quantitatively and without preconceived opinion the most relevant pair of roughness parameters that describe an abraded surface. The methodology was firstly validated on simulated fractal profiles having different amplitudes and Hölder exponents and it was secondly applied to characterise different worn regions of a retrieved metallic femoral head articulated against an ultrahigh molecular weight polyethylene (UHMWPE) acetabular cup containing an embedded metallic fibber into its surface. The methodology consists in combining the recent Bootstrap method with the usual discriminant analysis. It was validated on simulated fractal profiles showing that, among more than 3000 pairs tested, the total amplitude Rt and the fractal dimension Δ is the most relevant pair of roughness parameters; parameters corresponding to the variables modulated in the analytical expression of the fractal function. The application of this methodology on a retrieved metallic femoral head shows that the most relevant pair of parameters for discriminating the different investigated worn regions is the arithmetic roughness parameter Ra paired with the mean peak height Rpm. This methodology finally helps in a better understanding of the scratch mechanism of this orthopedic bearing component.

Scratch tests to contribute designing performance maps of multilayer polymeric coatings
http://hdl.handle.net/10985/9627
Scratch tests to contribute designing performance maps of multilayer polymeric coatings
RUDERMANN, Yann; IOST, Alain; BIGERELLE, Maxence
The scratching technique has gained interest in recent times because of the numerous inherent properties implied (adherence, hardness, elasticity, viscoelasticity, cohesion, etc.) during tests. Some singular mechanical responses have been noticed (cyclical slips and unsticking, degradation modes, etc.) and valued on multilayers polymeric coatings. The results allow differentiating them and illustrating the mare resistance for part. Scratch test is identified as one of the most efficient to build coating performance maps. The main purpose of our work related to the characterization of multilayers polymeric coatings, is to determine a set of experiments in order to compare their mar resistance. Experiments are made by indentation (hardness, creep, stress relaxation), scratch test (determination of the critical load), glossy reflection and wear. In this paper we describe the scratch experiments used to compare the mar resistance of the coatings. The parameters recorded are used to build a performance map relative to a specimen and this performance map is used to compare all characteristics of different multilayers coatings. Two organic systems are taken as samples to illustrate it. They are composed of three layers with a common steel sheet substrate and a common PET topcoat. The intermediary layer is soft and thick for the first product while it is hard and thin for the second one. The scratch results combined with other test results in performances maps underline the role of an intermediary layer in order finally to better design multilayer polymeric coatings.
Authors want to thank Stéphane Benayoun, LTDS Lyon, for his help in scratchtest experimentation and for fruitful discussions.
Sat, 01 Jan 2011 00:00:00 GMT
http://hdl.handle.net/10985/9627
20110101T00:00:00Z
RUDERMANN, Yann
IOST, Alain
BIGERELLE, Maxence
The scratching technique has gained interest in recent times because of the numerous inherent properties implied (adherence, hardness, elasticity, viscoelasticity, cohesion, etc.) during tests. Some singular mechanical responses have been noticed (cyclical slips and unsticking, degradation modes, etc.) and valued on multilayers polymeric coatings. The results allow differentiating them and illustrating the mare resistance for part. Scratch test is identified as one of the most efficient to build coating performance maps. The main purpose of our work related to the characterization of multilayers polymeric coatings, is to determine a set of experiments in order to compare their mar resistance. Experiments are made by indentation (hardness, creep, stress relaxation), scratch test (determination of the critical load), glossy reflection and wear. In this paper we describe the scratch experiments used to compare the mar resistance of the coatings. The parameters recorded are used to build a performance map relative to a specimen and this performance map is used to compare all characteristics of different multilayers coatings. Two organic systems are taken as samples to illustrate it. They are composed of three layers with a common steel sheet substrate and a common PET topcoat. The intermediary layer is soft and thick for the first product while it is hard and thin for the second one. The scratch results combined with other test results in performances maps underline the role of an intermediary layer in order finally to better design multilayer polymeric coatings.

Relation between entropy, free energy and computational energy
http://hdl.handle.net/10985/9733
Relation between entropy, free energy and computational energy
BIGERELLE, Maxence; ABDELAAL, Hisham; IOST, Alain
This paper proposes an isomorphism between the number of accessible states of the system including statistical fluctuation and the optimised size of a computer program setup by combining the Huffman and R.L.E algebrae. At first, a relation between the variation of the free energy in the system and the variation of the programme size used to describe the system was stated. A fluctuation to the equilibrium decreases the size of the programme in relation to the decrease in entropy and the decay of the free energy of the system.
Fri, 01 Jan 2010 00:00:00 GMT
http://hdl.handle.net/10985/9733
20100101T00:00:00Z
BIGERELLE, Maxence
ABDELAAL, Hisham
IOST, Alain
This paper proposes an isomorphism between the number of accessible states of the system including statistical fluctuation and the optimised size of a computer program setup by combining the Huffman and R.L.E algebrae. At first, a relation between the variation of the free energy in the system and the variation of the programme size used to describe the system was stated. A fluctuation to the equilibrium decreases the size of the programme in relation to the decrease in entropy and the decay of the free energy of the system.

Multiscale Roughness Analysis in InjectionMolding Process
http://hdl.handle.net/10985/10796
Multiscale Roughness Analysis in InjectionMolding Process
BIGERELLE, Maxence; VAN GORP, Adrien; IOST, Alain
The roughness of polymer surfaces is often investigated to guarantee both the surface integrity and the surface functionality. One of the major problems in roughness measurement analyses consists in determining both the evaluation length and the reference line (i.e., the degree of the polynomial equation) from which roughness parameters are computed. This article outlines an original generic method based on the generalized analysis of variance and experimental design methodology for estimating the most relevant roughness parameter p, the most pertinent scale, s, and finally, the degree of the polynomial fitting, d. This methodology is then applied to characterize the influence of four process parameters on the final roughness of poly(polypropylene) samples obtained by injection molding. This method allows us to determine the most efficient triplet (p, s, d) that best discriminates the effect of a process parameter q. It is shown that different (p, s, d) values are affected to each process parameter giving finally the scale on which each process parameter modifies the roughness of a polymeric surface obtained by injection molding. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Tue, 01 Jan 2008 00:00:00 GMT
http://hdl.handle.net/10985/10796
20080101T00:00:00Z
BIGERELLE, Maxence
VAN GORP, Adrien
IOST, Alain
The roughness of polymer surfaces is often investigated to guarantee both the surface integrity and the surface functionality. One of the major problems in roughness measurement analyses consists in determining both the evaluation length and the reference line (i.e., the degree of the polynomial equation) from which roughness parameters are computed. This article outlines an original generic method based on the generalized analysis of variance and experimental design methodology for estimating the most relevant roughness parameter p, the most pertinent scale, s, and finally, the degree of the polynomial fitting, d. This methodology is then applied to characterize the influence of four process parameters on the final roughness of poly(polypropylene) samples obtained by injection molding. This method allows us to determine the most efficient triplet (p, s, d) that best discriminates the effect of a process parameter q. It is shown that different (p, s, d) values are affected to each process parameter giving finally the scale on which each process parameter modifies the roughness of a polymeric surface obtained by injection molding. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers

Perimeter analysis of the Von Koch island, application to the evolution of grain boundaries during heating
http://hdl.handle.net/10985/9794
Perimeter analysis of the Von Koch island, application to the evolution of grain boundaries during heating
BIGERELLE, Maxence; IOST, Alain
This paper introduces an analyse of the fractal dimension by Richardson’s method. Two different ways to calculate the fractal dimension are presented with their related calculation errors and applied the Von Koch curves. A MonteCarlo simulation of the evolution of the grains’ boundaries when heating shows that the interfaces lose their fractal characteristics as reported in experimental work. This result is interpreted by dissipation of the energy during the evolution of the grain boundary.
Sun, 01 Jan 2006 00:00:00 GMT
http://hdl.handle.net/10985/9794
20060101T00:00:00Z
BIGERELLE, Maxence
IOST, Alain
This paper introduces an analyse of the fractal dimension by Richardson’s method. Two different ways to calculate the fractal dimension are presented with their related calculation errors and applied the Von Koch curves. A MonteCarlo simulation of the evolution of the grains’ boundaries when heating shows that the interfaces lose their fractal characteristics as reported in experimental work. This result is interpreted by dissipation of the energy during the evolution of the grain boundary.

Analyse de la rugosité obtenue par un nouveau procédé de tribofinition
http://hdl.handle.net/10985/10815
Analyse de la rugosité obtenue par un nouveau procédé de tribofinition; Analysis of the roughness obtained by a new polishing process
BIGERELLE, Maxence; IOST, Alain; ROCHER, Philippe
Nous proposons dans cet article d'analyser un nouveau procédé de polissage automatique : Ecoclean, qui est développé principalement pour la préparation de prothèses dentaires. En faisant varier les conditions expérimentales (matériau étudié, durée de traitement, présence ou non d'acide, présence ou non d'aiguilles) nous obtenons des états de surface différents. Pour chaque échantillon l'état de surface est caractérisé à l'aide d'un rugosimètre tactile et le calcul d'une centaine de paramètres de rugosité. Nous recherchons ensuite à l'aide du logiciel MESRUG, que nous avons développé dans notre laboratoire, les paramètres de rugosité qui sont les plus pertinents pour caractériser l'état de surface en fonction des conditions expérimentales. Le polissage automatique est comparé au polissage manuel. Cette méthode peut être utilisée pour définir les conditions expérimentales permettant d'obtenir un état de surface répondant à des critères de rugosité déterminés.; Usually, corrosion and mechanical resistance of dental prosthesis are affected by the surface roughness of the implant materials. This study aimed at evaluating the ability of a new polishing process: Ecoclean. For different dentalalloys, polishing was performed by varying testing conditions. A computerbased bootstrap method developed in our laboratory is then used to calculate more than one hundred roughness parameters from results recording on these samples by tactile profilometer and to correlate the roughness parameters with experimental conditions. The results were compared with mechanical polished samples one. This method allows us to determine the appropriate experimental conditions to obtain a given set of roughness parameters.
Mon, 01 Jan 2007 00:00:00 GMT
http://hdl.handle.net/10985/10815
20070101T00:00:00Z
BIGERELLE, Maxence
IOST, Alain
ROCHER, Philippe
Nous proposons dans cet article d'analyser un nouveau procédé de polissage automatique : Ecoclean, qui est développé principalement pour la préparation de prothèses dentaires. En faisant varier les conditions expérimentales (matériau étudié, durée de traitement, présence ou non d'acide, présence ou non d'aiguilles) nous obtenons des états de surface différents. Pour chaque échantillon l'état de surface est caractérisé à l'aide d'un rugosimètre tactile et le calcul d'une centaine de paramètres de rugosité. Nous recherchons ensuite à l'aide du logiciel MESRUG, que nous avons développé dans notre laboratoire, les paramètres de rugosité qui sont les plus pertinents pour caractériser l'état de surface en fonction des conditions expérimentales. Le polissage automatique est comparé au polissage manuel. Cette méthode peut être utilisée pour définir les conditions expérimentales permettant d'obtenir un état de surface répondant à des critères de rugosité déterminés.
Usually, corrosion and mechanical resistance of dental prosthesis are affected by the surface roughness of the implant materials. This study aimed at evaluating the ability of a new polishing process: Ecoclean. For different dentalalloys, polishing was performed by varying testing conditions. A computerbased bootstrap method developed in our laboratory is then used to calculate more than one hundred roughness parameters from results recording on these samples by tactile profilometer and to correlate the roughness parameters with experimental conditions. The results were compared with mechanical polished samples one. This method allows us to determine the appropriate experimental conditions to obtain a given set of roughness parameters.

Physical Interpretations of the Numerical Instabilities in Diffusion Equations Via Statistical Thermodynamics
http://hdl.handle.net/10985/9816
Physical Interpretations of the Numerical Instabilities in Diffusion Equations Via Statistical Thermodynamics
BIGERELLE, Maxence; IOST, Alain
The aim of this paper is to analyze the physical meaning of the numerical instabilities of the parabolic partial differential equations when solved by finite differences. Even though the explicit scheme used to solve the equations is physically well posed, mathematical instabilities can occur as a consequence of the iteration errors if the discretisation space and the discretisation time satisfy the stability criterion. To analyze the physical meaning of these instabilities, the system is divided in subsystems on which a Brownian motion takes place. The Brownian motion has on average some mathematical properties that can be analytically solved using a simple diffusion equation. Thanks to this mesoscopic discretisation, we could prove that for each half subcell the equality stability criterion corresponds to an inversion of the particle flux and a decrease in the cell entropy in keeping with time as criterion increases. As a consequence, all stability criteria defined in literature can be used to define a physical continuous 'timelength' frontier on which mesoscopic and microscopic models join.
Thu, 01 Jan 2004 00:00:00 GMT
http://hdl.handle.net/10985/9816
20040101T00:00:00Z
BIGERELLE, Maxence
IOST, Alain
The aim of this paper is to analyze the physical meaning of the numerical instabilities of the parabolic partial differential equations when solved by finite differences. Even though the explicit scheme used to solve the equations is physically well posed, mathematical instabilities can occur as a consequence of the iteration errors if the discretisation space and the discretisation time satisfy the stability criterion. To analyze the physical meaning of these instabilities, the system is divided in subsystems on which a Brownian motion takes place. The Brownian motion has on average some mathematical properties that can be analytically solved using a simple diffusion equation. Thanks to this mesoscopic discretisation, we could prove that for each half subcell the equality stability criterion corresponds to an inversion of the particle flux and a decrease in the cell entropy in keeping with time as criterion increases. As a consequence, all stability criteria defined in literature can be used to define a physical continuous 'timelength' frontier on which mesoscopic and microscopic models join.

Analyses of the Instabilities in the Discretized Diffusion Equations via Information Theory
http://hdl.handle.net/10985/10901
Analyses of the Instabilities in the Discretized Diffusion Equations via Information Theory
BIGERELLE, Maxence; NACEUR, Hakim; IOST, Alain
In a previous investigation (Bigerelle and Iost, 2004), the authors have proposed a physical interpretation of the instability λ = Δt/Δx2 > 1/2 of the parabolic partial differential equations when solved by finite differences. However, our results were obtained using integration techniques based on erf functions meaning that no statistical fluctuation was introduced in the mathematical background. In this paper, we showed that the diffusive system can be divided into subsystems onto which a Brownian motion is applied. Monte Carlo simulations are carried out to reproduce the macroscopic diffusive system. It is shown that the amount of information characterized by the compression ratio of information of the system is pertinent to quantify the entropy of the system according to some concepts introduced by the authors (Bigerelle and Iost, 2007). Thanks to this mesoscopic discretization, it is proved that information on each subcell of the diffusion map decreases with time before the unstable equality λ = 1/2 and increases after this threshold involving an increase in negentropy, i.e., a decrease in entropy contrarily to the second principle of thermodynamics.
Fri, 01 Jan 2016 00:00:00 GMT
http://hdl.handle.net/10985/10901
20160101T00:00:00Z
BIGERELLE, Maxence
NACEUR, Hakim
IOST, Alain
In a previous investigation (Bigerelle and Iost, 2004), the authors have proposed a physical interpretation of the instability λ = Δt/Δx2 > 1/2 of the parabolic partial differential equations when solved by finite differences. However, our results were obtained using integration techniques based on erf functions meaning that no statistical fluctuation was introduced in the mathematical background. In this paper, we showed that the diffusive system can be divided into subsystems onto which a Brownian motion is applied. Monte Carlo simulations are carried out to reproduce the macroscopic diffusive system. It is shown that the amount of information characterized by the compression ratio of information of the system is pertinent to quantify the entropy of the system according to some concepts introduced by the authors (Bigerelle and Iost, 2007). Thanks to this mesoscopic discretization, it is proved that information on each subcell of the diffusion map decreases with time before the unstable equality λ = 1/2 and increases after this threshold involving an increase in negentropy, i.e., a decrease in entropy contrarily to the second principle of thermodynamics.