ATOMOSYD

1995 A Wien-bridge oscillator

Letellier — 2022-05-01T17:50:05Z

In the 1980s, many electronic circuits producing chaotic regimes were proposed. Most of the proposed circuits are modifications of a LC circuit which is not convenient to produce audio and lower frequencies. The RC circuits are more acceptable for low frequencies but they are often rather complex. A. Namajhas and Arunas Tamasevicius proposed a simple electronic circuit made of a Wien bridge, a single opamp and a single nonlinear device displaying a current saturation characteristic . The (...) - Chaos in electronic circuits

Introduction à la circulation des fluides physiologiques (2022)

Letellier — 2022-04-21T09:09:46Z

3ème édition à paraître le 27 Septembre 2022
Les fluides physiologiques servent au transport de molécules impliquées dans le fonctionnement des grands organismes, des nutriments, de l'oxygène, etc. Par exemple, l'air est apporté aux poumons par la ventilation, le sang diffuse l'oxygène jusqu'aux muscles et extrait les "déchets" comme le dioxyde de carbone pour les éliminer du corps. Ce livre se présente comme une introduction à la mécanique des fluides nécessaire à une première approche de la circulation (...) - Books

2022

Letellier — 2022-03-15T05:36:09Z

I. Sendiña-Nadal & C. Letellier
Observability analysis and observer design of networks of Rössler systems
submitted ArXiv, 2203.07447, 2022. Online
Abstract
We address the problem of retrieving the full state of a network of Rössler systems from the knowledge of the actual state of a limited set of nodes. The selection of the nodes where sensors are placed is carried out in a hierarchical way through a procedure based on graphical and symbolic observability approaches. By using a map (...) - Papers

Les ErgoRameurs

Letellier — 2022-01-28T17:23:36Z

Quelques conseils
Réglage des sangles : elles doivent passer au niveau de l'articulation du pied
le facteur de résistance (drag factor en anglais) : c'est le coefficient de traînée qui permet de quantifier l'énergie dépensée par frottement lors du déplacement du bateau. Sur un bateau, il dépend du poids car, plus le rameur pèse, plus le bateau s'enfonce dans l'eau, et plus la traînée est importante. La FFA propose les valeurs ci-dessous :
ce que nous pouvons transformer en
le brevet Indoor (...) - News

1975 : A 2D predator-prey map

Letellier — 2021-09-25T17:31:54Z

In 1975, John Rex Beddington, C. A. Free and John Lawton proposed a map governing two interacting populations, preys and predators :
where xn designates the preys and yn the predators. This two-dimensional discrete map considers populations with non-overlapping generations and was based on Nicholson-Bailey host-parasite equations to describe the interactions between a population of herbivorous arthropods --- invertebrate animal having an exoskeleton --- and their insect parasitoïds. (...) - Discrete maps

2021 Des découvertes par des scientifiques émotifs

Letellier — 2021-06-23T06:02:40Z

Dans le cadre de la Fête de la Science 2021
Par Christophe Letellier
Cette conférence est publiée sur la chaine Héritages Scientifiques
Des découvertes par des scientifiques émotifs
Chercheurs normands : ils nous parlent de leurs découvertes !
Vous souhaitez poser des questions par message ? C'est ici
Cette conférence questionne ce qui peut susciter l'émotion chez le scientifique face à la découverte. Il est montré que l'émotion est d'autant plus évidente que l'obstacle à franchir (...) - Scientific Mediations

Patient-ventilator synchronization during non-invasive ventilation

Letellier — 2021-05-14T09:01:29Z

Datsets for nine patient receving NIV - Experimental data

2021

2021-01-12T14:40:38Z

S. Mangiarotti & C. Letellier
Topological characterization of toroidal chaos : A branched manifold for the Deng toroidal attractor
Chaos, 31, 013129, 2021. Online
Abstract
When a chaotic attractor is produced by a three-dimensional strongly dissipative system, its ultimate characterization is reached when a branched manifold—a template—can be used to describe the relative organization of the unstable periodic orbits around which it is structured. If topological characterization was completed (...) - Papers

2010 Multi-folded toroidal chaos

Letellier — 2020-12-13T06:19:17Z

As pointed out by Otto E. Rössler, to produce chaos, it is sufficient to combine an oscillator with a nonlinear switch. Here the oscillator is a relaxation oscillator containing a storage element represented by a capacitor, which is charged gradually through a resistor from the voltage source, and then discharged rapidly through a ‘‘threshold” element, such as a neon lamp. This element has to have in fact two distinct thresholds, one for ignition, and another, lower the extinguishing voltage. (...) - 3D flows

1983 A 4D model for the peroxidase-oxidase reaction

Letellier — 2020-11-14T18:15:00Z

The peroxidase-oxidase reaction involves an organic substance, commonly the reduced nicotinamide adenine dinucleotide NADH, is oxidised with molecular oxygen according to
Damped oscillations were first seen in 1965 The nonlinear behavior of the peroxidase-oxidase reaction was studied using structurally different peroxidases. : this study leads to the conclusion that the mechanisms responsible for oscillatory kinetics may vary from one peroxidase to the other. Soon after the simple model (...) - Biological & chemical models