Les Cars

Hybrid cars now, fuel cell cars later.

We compare the energy efficiency of hybrid and fuel cell vehicles as well as conventional internal combustion engines. Our analysis indicates that fuel cell vehicles using hydrogen from fossil fuels offer no significant energy efficiency advantage over hybrid vehicles operating in an urban drive cycle. We conclude that priority should be placed on hybrid vehicles by industry and government.

Les maladies causées par les anaérobies pathogènes sporulés chez les animaux domestiques

Background free CARS imaging by phase sensitive heterodyne CARS.

In this article we show that heterodyne CARS, based on a controlled and stable phase-preserving chain, can be used to measure amplitude and phase information of molecular vibration modes. The technique is validated by a comparison of the imaginary part of the heterodyne CARS spectrum to the spontaneous Raman spectrum of polyethylene. The detection of the phase allows for rejection of the non-re...

Les Rotations Et Les Quaternions

La construction du corps non commutatif H de quaternions est une variante plus compliquée de la construction du corps commutatif C de nombres complexes. Donc on commence en rappelant la construction de C à partir de R. Les nombres complexes s’écrivent a+ bi avec a, b ∈ R. Donc C est un espace vectoriel sur R de dimension 2 avec base {1, i}. La loi d’addition de C est celle que C possède en tant...

Turbulent Flow over Cars

In this paper the flow behaviour over a number of car bodies is studied. For this purpose the unsteady 2-D incompressible Navier-Stokes equations have been applied. After averaging and nondimensionalizing the equations, the system of equations has been transformed from the Cartesian (x-y) coordinates to a body fitted generalized (-) coordinate. As the flow is incompressible, the density in the ...