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Abstract: In this Note we show that the configuration spaces of an articulated arm of length k in gives rise to a natural tower of sphere bundles. Moreover, we prove that, each tower of projective bundles associated to special multi-flags, we can associate such a tower of sphere bundles which is a two-fold covering of the previous one. [Copyright &y& Elsevier]

To investigate the origin of a recurring anomaly that affects a rotomolded three-layer sandwich hull, we prospect numerically a way of instability by global buckling. Such alternative is suggested, on one hand by the final geometry at the return to the room temperature and, on the other hand by the unpredictable occurring of the anomaly. The thermo mechanical problem is set within a nonlinear framework and limited to the cooling sequence in solid phase after the degree of crystallinity has reached its saturation level. The non-linearities of the material are introduced through temperature-dependent evolutions and the geometrical ones at the interface mould/hull are all over taken into account through unilateral contact conditions. The computational of the unsteady thermo mechanical problem is carried out by means of the finite-element code Abaqus/Explicit and the thermal evolution adjustment is performed by a prediction-correction scheme for the gap conductance. To achieve the buckling analysis under thermo mechanical loading we make use of the linear perturbation method and the results we obtain are consistent with the defect so far suspected. Thus, the two first buckling modes computed are in a good agreement with the defects under the real conditions of the process. [ABSTRACT FROM AUTHOR]

This work concerns the dynamic and the thermal study between a heated rotating solid and a pulsatile flow evolving periodically in a cylindrical cavity. The reference frequency of pulsatile flow was determined by the evolution regime to his stationary state. The frequency varied from the 1/3 reference frequency to 10 once this value. The periodicity is assured by the periodical inlet conditions. The numerical study concerns the Reynolds number less than 100 and the Taylor number less than 500, in order to avoid the presence of instabilities in the flow. Two numerical methods have been used; the finite-elements method and the finite-differences combined with ADI scheme. The fluid considered is the air with constant physiques proprieties. The influence of ratio conductivity, K, between solid conductivity and fluid conductivity, has taken from K = 10-2 to K = 10+3. The influence of the two periodical combined motions; rotation of the solid and axial flow, on the thermal transfer mechanism is studied. The results show that the velocity components are in phase with the rate flow but the pressure and the different thermal parameters are in difference of phase. We note also the oscillatory shape of different dynamical and thermal parameters. The frequency influence appears at the greater values. The Nusselt number is proportional to the frequencies. The results are in good agreement with previous numerical and experimental studies. [ABSTRACT FROM AUTHOR]

In mechanical engineering background, the lab works of continuum mechanics are necessary for the students to put abstract knowledge such as stress and strain tensors into practice. In order to adapt these lab works to the demands of students, we have chosen to decompose theses lab works into experimental and numerical parts. The main purpose of this paper is to present an example of lab works (compression of a disk along a diameter) and to show the educational benefits of the chosen approach for student. [ABSTRACT FROM AUTHOR]

In metal cutting a large amount of the external energy supplied to the cutting system is converted into heat. Therefore, the study of the thermal phenomenon developed in the metal cutting process is of prime concern. This phenomenon has a great influence on many metal cutting variables as tool wear, residual stress, and part distortion. This article presents the experimental analysis of the temperature distribution in the three-dimensional cutting process. Specially designed thermal imaging equipment, included both hardware and software, was developed in order to determine the temperature distribution in the deformation zone. A detailed description of this equipment, its calibration procedure and a full analysis of the emissivity of the cutting system components (chip, tool, and workpiece) are discussed. The designed thermal imaging equipment was proven to be very powerful to analyze the influence of the cutting parameters (cutting speed, cutting feed, depth of cut, work material, tool geometry, and tool material) on this temperature distribution. This equipment can also be useful for the construction and validation of numerical and analytical models of the three-dimensional cutting process. [ABSTRACT FROM AUTHOR]

The article presents English and French abstracts on topics related to French history including the role of women in the Protestant Evangelizing of Tahiti, the mechanical industry in the 18th century, and the colonial violence and extreme right movements in Oran, Algeria, during the 1930s.