Stabilisation métabolique par introduction d’atomes de fluor : application aux benzothiadiazine 1,1-dioxydes agissant en tant que potentialisateurs AMPA

Poster (2009, May)

Stabilité des collyres à base de chlorhydrate de cystéine

in Pharmakon (1987), 69

Stabilité et chaos dans l’espace des phases : application aux écosystèmes marins

Master's dissertation (1997)

Stability analysis of an evaporating binary mixture

in Bulletin of the American Physical Society, Vol. 53, n°15 (2008, November 01)

Rayleigh-Bénard-Marangoni instabilities in an evaporating binary mixture, consisting of a solvent and a solute of weak concentration, are studied theoretically. Local thermodynamic equilibrium is assumed ... [more ▼]

Rayleigh-Bénard-Marangoni instabilities in an evaporating binary mixture, consisting of a solvent and a solute of weak concentration, are studied theoretically. Local thermodynamic equilibrium is assumed at the flat gas-liquid interface. Solvent evaporation and air absorption in the liquid are neglected. At a certain height above the interface, the temperature and the concentration are fixed. One of the goals of the study is to track down the effects of this artifact on the results. Non-linear quasi-stationary basic profiles (due to evaporation) of the temperature and the solute concentration in the gas phase are considered, while the temperature distribution in the liquid is assumed to be linear and quasi-stationary. For the solute concentration in the liquid phase, two variants of the reference solution are studied, one just linear and quasi-stationary, whereas the other involves a fully transient non-linear profile. The latter is a more realistic option, given the relatively slow diffusion time in the liquid. A linear stability analysis is then carried out numerically, and illustrated for an aqueous solution of ethyl alcohol. [less ▲]

Stability analysis of the evaporation of a binary liquid into an inert gas, considering solute/thermal and gravity/surface tension effects

in Proceedings (CD) of the EUROTHERM Seminar Nr. 84 “Thermodynamics of phase changes”, Namur (Belgium), May 24-27, 2009 (2009)

The stability and accuracy of the uvby system.

in Calibration of Fundamental Stellar Quantities (1985)

Not Available

Stability and Limit Cycle Oscillation Amplitude Prediction for Multi-DOF Aeroelastic Systems with Piecewise Linear Non-Linearities

in Proceedings of the 2004 International Conference on Noise and Vibration Engineering (2004, September)

Discontinuous non-linearities such as freeplay and bilinear stiffness are often encountered in aeroelastic systems, sometimes as a result of wear and tear. It is important to predict the effect of such ... [more ▼]

Discontinuous non-linearities such as freeplay and bilinear stiffness are often encountered in aeroelastic systems, sometimes as a result of wear and tear. It is important to predict the effect of such non-linearities on the dynamic behaviour of a system, so that adequate safety guidelines can be drafted. As a consequence, the prediction of the bifurcation behaviour of a system featuring a discontinuous nonlinearity is crucial. Additionally, the post-bifurcation behaviour of the system is also of interest since it may consist of relatively harmless Limit Cycle Oscillations (LCO) of low amplitude or of unexpected catastrophic high amplitude LCOs. In this paper the bifurcation and post-bifurcation behaviour of a simulated Multi-DOF aeroelastic system with bilinear and freeplay nonlinearities are investigated using the Harmonic Balance method and a novel method for the prediction of the bifurcation conditions and LCO amplitudes. The method is based on the fact that the nonlinearities investigated are piecewise linear. The ratios of the real parts of the system eigenvalues in the various ranges of the bilinear spring are used in order to infer LCO amplitude information. By means of a demonstration on a simulated aeroelastic system with piece-wise linear stiffness, it is shown that the proposed approach is successful in yielding the full bifurcation and post-bifurcation behaviour of the system. Comparison of the amplitude predictions obtained from the Harmonic Balance technique and the Piecewise Linearisation proposed approach show that the latter are more consistent and closer to the true amplitudes throughout the airspeed range. The bifurcation analysis is extended to the special case where the inner stiffness of the bilinear spring is equal to zero, i.e. freeplay stiffness. It is shown that the Piecewise Linear analysis fails to capture the bifurcation behaviour for this case, while the Harmonic Balance method still produces some accurate predictions. [less ▲]

Stability and Structural Analysis of Alpha-Amylase from the Antarctic Psychrophile Alteromonas Haloplanctis A23

in European Journal of Biochemistry (1994), 222(2), 441-7

The alpha-amylase secreted by the antarctic bacterium Alteromonas haloplanctis displays 66% amino acid sequence similarity with porcine pancreatic alpha-amylase. The psychrophilic alpha-amylase is however ... [more ▼]

The alpha-amylase secreted by the antarctic bacterium Alteromonas haloplanctis displays 66% amino acid sequence similarity with porcine pancreatic alpha-amylase. The psychrophilic alpha-amylase is however characterized by a sevenfold higher kcat and kcat/Km values at 4 degrees C and a lower conformational stability estimated as 10 kJ.mol-1 with respect to the porcine enzyme. It is proposed that both properties arise from an increase in molecular flexibility required to compensate for the reduction of reaction rates at low temperatures. This is supported by the fast denaturation rates induced by temperature, urea or guanidinium chloride and by the shift towards low temperatures of the apparent optimal temperature of activity. When compared with the known three-dimensional structure of porcine pancreatic alpha-amylase, homology modelling of the psychrophilic alpha-amylase reveals several features which may be assumed to be responsible for a more flexible, heat-labile conformation: the lack of several surface salt bridges in the (beta/alpha)8 domain, the reduction of the number of weakly polar interactions involving an aromatic side chain, a lower hydrophobicity associated with the increased flexibility index of amino acids forming the hydrophobic clusters and by substitutions of proline for alanine residues in loops connecting secondary structures. The weaker affinity of the enzyme for Ca2+ (Kd = 44 nM) and for Cl- (Kd = 1.2 mM at 4 degrees C) can result from single amino acid substitutions in the Ca(2+)-binding and Cl(-)-binding sites and can also affect the compactness of alpha-amylase. [less ▲]

A stability diagram computation method for milling adapted to automotive industry

Conference (2006, June)

In this paper, a numerical method to compute stability diagrams is presentd. It is adapted to the particular case of automotive parts production where chatter arises due to the lack of stiffness of the ... [more ▼]

In this paper, a numerical method to compute stability diagrams is presentd. It is adapted to the particular case of automotive parts production where chatter arises due to the lack of stiffness of the workpiece. The main features of the model are the simultaneous immersion of many teeth, frequency domain computations and the use of the Finite Element Method to provide transfer function. [less ▲]

Stability For A Class of Homogeneous Hybrid Systems By Annular Lyapunov Analysis

in 49th IEEE Conference on Decision and Control (cdc 2010) (2010)

For a class of homogeneous hybrid systems we present a set of annular Lyapunov-like conditions for inferring global pre-asymptotic stability of systems. Then, we prove that such conditions are mild ... [more ▼]

For a class of homogeneous hybrid systems we present a set of annular Lyapunov-like conditions for inferring global pre-asymptotic stability of systems. Then, we prove that such conditions are mild, namely, that each globally pre-asymptotically stable system must satisfy them. Based on these results, we design a sum of squares algorithm that constructs a suitable Lyapunov-like function to fulfill such annular conditions. Finally, based on recent results on homogeneous approximations of hybrid systems, we point out that such conditions can also be used to deduce local pre-asymptotic stability for a wider class of hybrid systems. [less ▲]