A Social Identity Approach to Sport Psychology: Principles, Practice, and Prospects.

Drawing on social identity theory and self-categorization theory, we outline an approach to sport psychology that understands groups not simply as features of sporting contexts but rather as elements that can be, and often are, incorporated into a person's sense of self and, through this, become powerful determinants of their sport-related behavior. The underpinnings of this social identity approach are outlined, and four key lessons for sport that are indicative of the analytical and practical power of the approach are presented. These suggest that social identity is the basis for sports group (1) behavior, (2) formation and development, (3) support and stress appraisal, and (4) leadership. Building on recent developments within sport science, we outline an agenda for future research by identifying a range of topics to which the social identity approach could fruitfully contribute

Identity crisis: A theoretical analysis of ‘team identification’ research.

Research question: Existing team identification research uses various definitions, conceptualisations, and theoretical frameworks. In this paper, we provide a theoretical analysis of previous research using the two dominant theoretical approaches: identity theory and the social identity approach. Our primary purpose is to provide a theoretical framework for the on-going study of ‘team’ identification in sport management research. Findings: Scholars have used identity theory (role) and the social identity approach (group) in their quest to understand team identification, however, limited attention has been paid to the differences between the two frameworks. We focus on two aspects of role and group identification that epitomize divergence in terms of analytical focus and explanations for behavior: the basis for identification and salience. Implications. The manuscript concludes with three recommendations for future research. First, with the aim of making future research more specific, we recommend the use of fan (spectator) identification in studies using identity theory and team identification (organisation / brand) in studies exploring the influence of group identity. Second, we outline definitions for role (fan) and group (team) identification in sport research. Finally, we reflect on the measurement of team identification

Sintering mechanisms of metals under electric currents

International audienceThis chapter concerns the microscopic mechanisms involved in densifi-cation of metallic powders submitted to high electric current pulses like in the SPS technique. Because metallic systems exhibit high electric conductivity, focus is made on evaluating the sensitivity of the densification mechanisms on the current. Thus, a first part is devoted to the influence of electric currents on elementary met-allurgical phenomena (diffusion, plasticity…) which are involved in densification. Then, after recalling the micromechanical models of densification, the SPS kinetics is described, and analyzed in the framework of these models, with emphasis on the role of the current. Finally, theoretical and experimental investigations on electrically induced mechanisms at the scale of the powder particle contacts, are presented: dielectric breakdown of oxide layers, arcs and plasma, Joule overheating, electroplasticity and electromigration. Then, conclusions are drawn on the most probable mechanisms, and on the role of the current

FRITTAGE SOUS CHARGE D'UNE POUDRE AGGLOMEREE : REACTION D'INTERFACE EXTERNE

Nous présentons un modèle de réarrangement des grains permettant d'interpréter la première étape du frittage sous charge d'un échantillon. Ce modèle repose sur le calcul de la vitesse de descente de l'interface supérieure du comprimé ; les équations obtenues ne comportent qu'un paramètre ajustable (la vitesse de réarrangement des grains), elles mettent en évidence pour la première fois l'influence de la masse de l'échantillon sur les cinétiques de frittage sous charge.A model of grain rearrangement is presented which allows to interpret the first step of the hot-pressing kinetics. This model is based on the calculation of the interface down-stroke of the sample. The proposed equations contain only one adjustable parameter (the particle rearrangement rate), they point out for the first time the influence of the mass sample on the hot pressing kinetics

Cinétique de frittage d'une poudre agglomérée : le nitrure d'aluminium

La particularité du frittage d'une poudre agglomérée provient de l'existence de pores entre agglomérats, de grande dimension par rapport à celle des pores entre grains élémentaires.Cette porosité induit des phénomènes nouveaux qui peuvent être décrits au moyen de deux nouvelles variables : les densités relatives interagglomérat ρe et intraagglomérat ρi.On montre que les cinétiques de frittage doivent être étudiées à microstructure identique (ρe et ρi données) et non plus à densité relative moyenne fixée. Après l'étape de rearrangement, ces cinétiques peuvent être suivies à l'aide d'une carte de frittage, représentant l'évolution de ρe en fonction de ρi. Cette carte permet de décrire les trajectoires optimales et d'exprimer les valeurs optimales pour la température et la granulométrie.L'ensemble de cette analyse est confirmé par une étude expérimentale sur le nitrure d'aluminium aggloméré