Diffusion élastique et inélastique des protons de 155 MeV sur le carbone

Elastic and inelastic scattering differential cross-sections of 155 MeV protons by carbon have been studied by a scintillation telescope between 5° and 60°. Excitation levels of 4.4-9.6-15 and 20 MeV have been investigated.Nous avons déterminé par télescope à scintillateurs et en fonction de l'angle de diffusion, entre 5° et 60°, les sections efficaces différentielles de diffusion élastique et inélastique avec excitation du noyau de carbone aux niveaux de 4,4-9,6-15 et 20 MeV

Qualification and frequency accuracy of the space-based primary frequency standard PHARAO

International audienc

BEM analysis for curved cracks

The boundary integral equations (BIE) and displacement discontinuity methods (DDM) are formulated for solution of smooth curved crack problems within 2D elasticity and Reissner's plate bending theory. The equivalence between the direct boundary element method and the indirect boundary element method is shown here. The Chebyshev polynomials of the second kind are employed to solve the integral equations numerically. This enables determination of the stress intensity factors at the crack tips directly5 by the coefficients of Chebyshev polynomials. In the DDM, the coefficients of stress influence for the constant displacement discontinuity element are derived in closed form for the Reissner's plate bending problem. The degree of convergence of BIE is demonstrated with increasing numbers of the collocation points. Comparison is made with the analytical solutions from the stress intensity factor handbook for an embedded circular crack in a flat plate under tensile force. High accuracy of the presented numerical solutions makes possible to use them as benchmarks to evaluate the degree of accuracy for any numerical algorithms