The behavior of statically-indeterminate structural members and frames with cracks present

Arts et Métiers ParisTech, invitation en tant que professeur invité de Paul C. Paris au LAMEFIPCrack stability is discussed as affected by their presence in statically-indeterminate beams, frames, rings, etc. loaded into the plastic range. The stability of a crack in a section, which has become plastic, is analyzed with the remainder of the structure elastic and with subsequent additional plastic hinges occurring. The reduction of energy absorption characteristics for large deformations is also discussed. The methods of elastic–plastic tearing instability are incorporated to show that in many cases the fully plastic collapse mechanism must occur for complete failure.The authors acknowledge Arts et Metiers Paris Tech and Foundation Arts et Metiers for the financial support of the Prof. P.C. Paris’ stay at LAMEFIP in 2008 and 2009. The encouragement of Prof. Ivan Iordanoff, Director of LAMEFIP, is also acknowledged with thanks

The design of surfaces, between empathy and new figuration

Nowadays design languages seem anew defined through images and figures that appear increasingly distant from abstraction. In the time that we live in, where it is prevailing a dominance of individual needs rather common desires, an abandon of abstraction in favour of new figuration, stimulates the opportunity to investigate a new dyad, ‘Project and Empathy’; these terms could summarize well the expanded modality of physical and psychological interaction between people – as individual – and artefacts, through the increasing role of surfaces. The whole world of postmodern image, especially through the digital technologies, tends to offer hyper realistic aesthetic simulacra, altered nature: this is the current world of extension of feelings and sense, in which we are immersed daily. This condition affect the approaches to design, which require a new thinking around technologies, method and tools from training to practice the activity of design: a new attitude for materiality of things, beyond the immateriality of digital reality

Irreducible Coxeter groups

We prove that a non-spherical irreducible Coxeter group is (directly) indecomposable and that a non-spherical and non-affine Coxeter group is strongly indecomposable in the sense that all its finite index subgroups are (directly) indecomposable. We prove that a Coxeter group has a decomposition as a direct product of indecomposable groups, and that such a decomposition is unique up to a central automorphism and a permutation of the factors. We prove that a Coxeter group has a virtual decomposition as a direct product of strongly indecomposable groups, and that such a decomposition is unique up to commensurability and a permutation of the factors

From braid groups to mapping class groups

This paper is a survey of some properties of the braid groups and related groups that lead to questions on mapping class groups

Mapping class groups of non-orientable surfaces for beginners

The present paper are the notes of a mini-course addressed mainly to non-experts. It purpose it to provide a first approach to the theory of mapping class groups of non-orientable surfaces

Emotional Outbursts and Their Effects on Peer Relations in the Preschool Classroom

Emotions and emotion regulation play a role in a child’s interactions with their peers. This study uses observations collected in two preschool classrooms to address the questions of what causes emotional outbursts and how emotional outbursts affect the children involved. In this study, an emotional outburst is defined as an occurrence in which the child is making loud noises and having a physical reaction to an event that has just occurred. Participants were 22 children from the ages of three to five years old. Observational data were collected, and analyzed through categorization and interpretation, and results from this study suggest that there are many common causes of emotional outbursts in the children observed. The findings do not indicate obvious effects of emotional outbursts on children in the vicinity of the outburst

SIDATIM: assessing the potential of new biomass crops and valuable timber trees in agroforestry systems

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Artin groups of spherical type up to isomorphism

We prove that two Artin groups of spherical type are isomorphic if and only if their defining Coxeter graphs are the same