Search results for "Reactive"

CFD simulations

2022

Quantum dynamics of the oxygen isotopic exchange : lifetimes of metastable states of the ozone intermediate complex

2021

This thesis aims to describe the ozone dynamics during the isotopic exchange reactions of oxygen of type xO + yO zO (xO yO zO)* xO yO + zO, where x, y and z are the atomic masses of the stable oxygen isotopes (16, 17, 18). Firstly, we analyze several methods of accurate description of the atom interactions and numerical schemes to obtain the observables for the collision. Then, in a full-quantum hyperspherical formalism, we study the actual dynamics of the reactive process O + O2 -> O3* -> O2 + O. The metastable ozone created can then either decompose into oxygen by the inverse reaction, or relax into stable ozone by exchanging energy with the environment, typically N2 or O2 molecules. Thes…

Trehalose and trehalose-6-phosphate induce stomatal movements and interfere with ABA-induced stomatal closure in grapevine

2015

Aims: The effects of trehalose and trehalose-6-phosphate (T6P), among other sugars, were assessed on grapevine stomatal movements. Methods and results: Epidermal peels were used to assess the effects of sugars. Low concentrations of trehalose and T6P (1 μM) induced an osmotic-independent reduction of the stomatal aperture in light conditions. Furthermore, ABA-induced stomatal closure was reduced by sugar application in association with lower accumulation of reactive oxygen species in guard cells. Similar effects, although weaker, were observed in response to the disaccharides sucrose and maltose, but not in response to the monosaccharides fructose and glucose. Conclusion: This study clearly…

Détection hypothalamique de l’hyperglycémie : rôle de la dynamique mitochondriale dans la signalisation par les espèces actives de l’oxygène

2011

Characterization and role of nitric oxide production in Arabidopsis thaliana defense responses induced by oligogalacturonides

2011

Nitric oxide (NO) regulates a wide range of plant processes from development toenvironmental adaptation. In this study, NO production and its effects were investigated in aplant-pathogen context. The production of NO following Arabidopsis treatment witholigogalacturonides (OGs), an endogenous elicitor of plant defense, was assessed using the NOsensitive probe 4, 5-diamino fluorescein diacetate. Pharmacological and genetic approaches wereused to analyze NO enzymatic sources and its role in the Arabidopsis thaliana /Botrytis cinereainteraction. We showed that NO production involves both a L-arginine- and a nitrate reductase(NR)-pathways. OGs-induced NO production was Ca2+-dependent and modula…

The role of NtRBOHD in regulation of response to cryptogein in tobacco cells

2014

International audience

Acoustic properties of plates with unevenly distributed macro perforations backed by woven meshes

2012

A hybrid model describing the acoustic properties of plates with macro-perforations that can be unevenly distributed on the plate surface and backed by woven or precision woven meshes with microscopic perforations is proposed. The plate perforations may be of circular or rectangular shapes. Since the perforated plate may not necessarily be considered as an equivalent fluid, its surface impedance is calculated by the Maa model [Noise Control Eng. J. 29, 77-84 (1987)], whereas the Johnson-Champoux-Allard model [J. Appl. Phys. 70, 1975-1979 (1991)] is used for the mesh. It is observed that the absorption of the carrying plate seems to depend on the hydraulic diameter of the perforations and no…

Caractéristiques des réactions endothermiques d'interface

1981

The knowledge of the different thermodynamic states of an evaporative interface leads us to propose a formulation of the evolution laws (evaporation rate vs pressure) adapted to each regime (interfacial equilibrium or non equilibrium). Starting from fluid dynamics and irreversible thermodynamics, the model is able to determine the interface flux-forces relations which express the transport coefficients and the thermodynamic coupling effects. The theoretical results are compared to experimental data relative to water evaporation al T =313 K. Taking into account the different regimes arising for the deviation from equilibrium, the model reproduces quantitatively the experimental kinetic curve…

Caractéristiques des réactions endothermiques d'interface. Recherche des états thermodynamiques d'interface en relation avec les écarts à l'équilibre…

1981

International audience; L'endothermicité de la vaporisation peut donner des propriétés particulières à l'interface. L'exploration de la carte thermique du système associée à un modèle permet d'accéder aux profils thermiques dans chaque phase et d'établir les températures à l'interface; ses différents états thermodynamiques sont en relation avec l'écart à l'équilibre du système : équilibre interfacial près de l'équilibre, puis apparition d'une discontinuité de température, enfin déséquilibre de température et de potentiel chimique.

Rôle du flux thermique à l'interface dans l'interprétation de l'effet Smith Topley

1975

International audience