Une formulation variationnelle du problème de contact avec frottement de Coulomb

International audienceA variational relationship is proposed as the weak form of the large deformation contact problem with Coulomb friction. It is a mixed relationship involving both the displacements and the multipliers; the weighting functions are the virtual displacements and the virtual multipliers. It is shown that the proposed weak form is equivalent to the strong form of the initial/boundary value contact problem and the multipliers are equal to the contact tractions.Dans ce travail, on propose une formulation variationnelle du problème de contact en grandes transformations avec frottement de Coulomb. Il s'agit d'une formulation mixte où les champs inconnus sont à la fois le champ des déplacements et le champ des multiplicateurs, et où les fonctions poids sont le champ des déplacements virtuels et le champ des multiplicateurs virtuels. On montre que le problème faible proposé équivaut bien au problème fort de contact et que les multiplicateurs sont égaux aux contraintes de contact

A century of trends in adult human height

Being taller is associated with enhanced longevity, and higher education and earnings. We reanalysed 1472 population-based studies, with measurement of height on more than 18.6 million participants to estimate mean height for people born between 1896 and 1996 in 200 countries. The largest gain in adult height over the past century has occurred in South Korean women and Iranian men, who became 20.2 cm (95% credible interval 17.5-22.7) and 16.5 cm (13.3-19.7) taller, respectively. In contrast, there was little change in adult height in some sub-Saharan African countries and in South Asia over the century of analysis. The tallest people over these 100 years are men born in the Netherlands in the last quarter of 20th century, whose average heights surpassed 182.5 cm, and the shortest were women born in Guatemala in 1896 (140.3 cm; 135.8-144.8). The height differential between the tallest and shortest populations was 19-20 cm a century ago, and has remained the same for women and increased for men a century later despite substantial changes in the ranking of countries

Intelligent Urban Transportation System to Control Road Traffic with Air Pollution Orientation

Enhancing transportation services and reducing vehicle emissions at intersections are main challenges for megacities. In this paper, an Intelligent Urban Transportation System is proposed as smart green traffic lights. In this context, vehicles are detected, and categorised. Furthermore, emission factors of each vehicle category are specified and used as an additional factor to optimize the traffic light cycle. IUTAR dashboard has also been developed and presented in this paper