A discrete element model to investigate sub-surface damage due to surface polishing

International audienceLarge high-power laser facilities such as megajoule laser (LMJ) or National Ignition Facility (NIF) are designed to focus about 2 MJ of energy at the wavelength of 351 nm, in the center of an experiment chamber. The final optic assembly of these systems, operating at 351 nm is made of large fused silica optics working in transmission. When submitted to laser at the wavelength of 351 nm, fused silica optics can exhibit damage, induced by the high amount of energy traversing the part. The created damage is a set of micro-chips that appear on the optic surface. Current researches have shown that this damage could be initiated on pre-existing sub-surface damages created during the optics manufacturing process. It is then very important to understand, for various set of manufacturing parameters, what are the key parameters for sub-surface damage. The presented work details the development of a simplified model to investigate the polishing process. Both silica (the material to be polished) and the abrasive particles are modeled using a discrete element approach. This numerical tool allows following the evolution of micro-cracks inside the material during the abrasion process. It is shown how the mechanical properties (pressure), the abrasive properties (shape and quantity of abrasive particles) and the system properties (filtration) have an influence on the sub-surface properties at the end of the process

Middle Neolithic farming of open-air sites in SE France: new insights from archaeobotanical investigations of three wells found at Les Bagnoles (L'Isle-sur-la-Sorgue, Dépt. Vaucluse, France)

Previous reviews of Middle Neolithic agricultural practice (4400–3500 cal bc) in southern France have highlighted a change in crop assemblages after 4000 cal bc, with a reduction of naked wheat and an increase of emmer and partly of einkorn. The recent investigation of three wells from the site of Les Bagnoles (4250–3800 cal bc) in the periphery of the southern Rhône valley yielded an unprecedented amount of waterlogged uncharred and charred plant macro remains that offer new insights into crop diversity and its changes over time. The results from the wells at Les Bagnoles were compared with other dated sunken features from open-air sites (in contrast to caves and rock shelters), with the aim of identifying patterns sug-gesting changes in the crop spectra between the early (MN1) and late (MN2) Middle Neolithic phases from taphonomically comparable contexts. The results from Les Bagnoles demonstrate that oil crops and pulses are underrepresented in dry sites and that they were a significant part of Middle Neolithic agriculture. They also indicate an increase in the representation of einkorn (instead of emmer) during MN2 that is also visible in other open-air sites. The comparison of the archaeobotani-cal results with silo storage capacity values as a proxy for average production capacity per household leads us to propose a possible drop in naked wheat productivity and opens new questions in factors affecting crop choice at the beginning of the 4th millennium cal bc

Penser des catégories objectives de classification musicale : l'exemple des intermédiaires techniques

Le de\u301bat contemporain autour des formes de la le\u301gitimite\u301 culturelle s\u2019organise autour de deux positions ayant tendance a\u300 s\u2019opposer. L\u2019une, qui trouve ses racines dans les travaux de Pierre Bourdieu sur la distinction (Bourdieu, 1979), insiste sur le lien entre pratiques culturelles et stratification sociale. Par pratiques culturelles, il faut entendre non seulement les objets culturels en tant que tels, hie\u301rarchise\u301s sur le plan de la le\u301gitimite\u301 culturelle inspire\u301e par un ordre de domination sociale, mais e\u301galement et surtout les modes d\u2019appropriation de ces objets culturels, caracte\u301ristiques d\u2019un habitus propre a\u300 une classe sociale, permettant aux pairs de se reconnaitre entre eux et d\u2019exclure les exte\u301rieurs et les parvenus (Coulangeon, 2010 ; Jarness, 2015 ; Schwarz, 2015). La seconde trouve son origine dans les travaux de Peterson & Kern (1996), qui affirment l\u2019e\u301mergence d\u2019une nouvelle forme de le\u301gitimite\u301 culturelle qui trouverait sa source dans l\u2019e\u301clectisme des gou\u302ts plus que dans la mai\u302trise d\u2019une pratique culturelle le\u301gitime (voir aussi Sonnett, 2016 ; Bryson, 1996). Ces deux approches, qui tendent a\u300 e\u302tre oppose\u301es, sont en re\u301alite\u301 assez comple\u301mentaires (Coulangeon, 2003). En effet, on peut voir dans l\u2019approche e\u301clectique des objets culturels une forme d\u2019appropriation culturelle, un modus operandi de\u301coulant d\u2019un habitus de classe. Dans cette perspective, l\u2019e\u301mergence d\u2019une nouvelle forme de le\u301gitimite\u301 culturelle te\u301moignerait d\u2019un changement structurel dans les stratifications sociales. Inversement, la notion d\u2019 \uab omnivore \ubb re\u301pond efficacement a\u300 l\u2019un des de\u301fauts de la the\u301orie bourdieusienne de la le\u301gitimite\u301 culturelle, a\u300 savoir la tendance a\u300 conside\u301rer comme relativement unilate\u301rales et monocordes les pratiques culturelles d\u2019un groupe donne\u301 (Lahire, 2004). Afin de se de\u301tacher de la controverse et de rassembler les deux perspectives, il apparait utile de pointer un de\u301faut commun aux deux approches : le fait que les analyses soient base\u301es sur un de\u301coupage du phe\u301nome\u300ne musical en genres, ce qui implique plusieurs biais. Tout d\u2019abord, un genre musical est une notion floue, une frontie\u300re symbolique (Lamont et Molna\u300r, 2002) dont la de\u301finition est l\u2019objet de luttes sociales. D\u2019un agent social a\u300 un autre, ce n\u2019est pas le me\u302me objet que de\u301signe \uab musique classique \ubb, \uab varie\u301te\u301s \ubb, \uab jazz \ubb, \uab grindcore expe\u301rimental \ubb. Par ailleurs, les travaux sur la pluri-activite\u301 des musiciens (Bureau et al., 2009) ainsi que les ethnographies des mondes musicaux (Rudent, 2008 ; Lehmann, 2002 ; Perrenoud, 2007) montrent que si les genres musicaux sont vecteurs de conventions qui permettent la pratique musicale, ceux-ci ne se transcrivent pas ne\u301cessairement en frontie\u300res sociales, le musicien appartenant d\u2019abord a\u300 son instrument et a\u300 un statut social (comme celui de l\u2019intermittence) avant de s\u2019identifier a\u300 un genre musical. Dans la re\u301ception comme dans la production, la notion de genre apparait donc inade\u301quate a\u300 l\u2019e\u301tude des liens entre stratification sociale et pratiques culturelles. C\u2019est pourquoi nous proposons une autre approche du de\u301coupage du phe\u301nome\u300ne musical qui se baserait sur les travaux d\u2019Edward Kealy (1979). Celui-ci a mis en e\u301vidence un lien direct entre la relation de travail musicien - technicien et l\u2019esthe\u301tique musicale du re\u301sultat de leur collaboration. Il montre que l\u2019e\u301mergence du rock dans les anne\u301es 60-70 est directement lie\u301e aux e\u301volutions de cette relation, et qu\u2019a\u300 trois grands types d\u2019esthe\u301tiques correspondent trois grands types de relation. Malgre\u301 ces re\u301sultats et l\u2019omnipre\u301sence des techniciens dans la production musicale contemporaine, le sujet est reste\u301 tre\u300s peu e\u301tudie\u301. Nous proposons de mettre a\u300 jour ces travaux et d\u2019analyser les liens contemporains qui unissent rapports de travail musiciens-techniciens et esthe\u301tiques musicales, afin d\u2019offrir un regard renouvele\u301 sur les liens entre stratifications sociales et frontie\u300res symboliques

Conventions in a non-professional art world : an application of Peterson's production of culture perspective

Richard Peterson\u2019s \uab\ua0production of culture perspective\ua0\ubb describes six \uab\ua0facets\ua0\ubb that are sources of influence on the process of production of a cultural object : technology, law and regulation, industry structure, organization structure, occupational careers, and market (Peterson & Anand, 2004). Moreover, it also insists on the fact that a change in one of the facets implies a change in all the others. We will focus here our interest on the changes implied by an \uab\ua0industry structure\ua0\ubb rather undetermined, through the study of a production organisation that presents the particularity to finance itself without relying on the market or on public subsidies. Between March and June 2014, we realized the ethnographic study, through interview and participant observation, of a nonprofit association producing and broadcasting musical videoclips on the internet. To ensure its productions, this association has been relying only on the personal resources of its members from May 2013 to June 2014. Following the guideline of filming local musicians playing one original composition in noteworthy places of the city they are living in (Toulouse, France), they have been able to ensure the broadcast, using internet platforms (Youtube, Vimeo, Facebook), of one original video each Sunday. This regularity resulted in the gathering of enough visibility to successfully launch a crowdfunding raising campaign for an amount of more than a thousand euros in June 2014. We will discuss the consequences that this particular \uab\ua0business model\ua0\ubb, that does not implies the direct use of money but mostly relies on cultural and social capital to mobilize human and material resources, can have on the other facets of the Peterson\u2019s model. Through the informations obtained during the study and their analysis, we first observe that the productions of the association are both situated on the restricted and great production markets (Bourdieu, 1971). Then, we will see how the association is used as a training field for the personal carrier of its members (Portelli, 1993 ; Vermeersch, 2004), a dynamic that is somehow made possible by the particular employment system of \uab\ua0intermittence du spectacle\ua0\ubb (Menger, 2011). Finally, we will show that the organization is structured to allow collegial construction of the aesthetics of the videos, in the limits of several non-negotiable conventions designed to ensure the continuity of the partnership between all the actors involved. Thus, we will see that this situation provides a typical case to study how exogenous interests define boundaries for endogenous contents (Kaufmann, 2004)

Technical work in music : Towards a new category of actors in musical and artistic works

\uab Roadies \ubb, \uab Sound engineers \ubb, \uab Sound designers \ubb, \uab Sound technicians \ubb are common actors of musical art worlds. They are systematically present wherever sound-reproducing technologies are used. Wherever musicians play in a microphone, the sound is caught, mixed, recorded and/or amplified in order to be listened on speakers, either in the same time and place in the case of a live show, either in another time and place in the case of recorded music, either in the same time and in another place in the case of a live broadcast. In each case, technicians are employed in order to ensure the good transmission of the sound from the musician to the ears of the audience. Despite this systematic presence, the role of these actors in musical production, as well as their social trajectories, are clearly understudied in sociology. In his classical book, Howard Becker classifies technicians as \uab support personnel \ubb, a form of miscellaneous category \uab designed to hold whatever the other categories do not make an easy place for \ubb (Becker, 1984 :2). The more recent stream of research around cultural intermediaries (Negus, 2002 ; Wright, 2005 ; Hesmondalgh, 2006 ; Maguire & Matthews, 2010) could have paved the way towards their study, but empirical works (Cronin, 2004 ; Entwistle, 2006 ; Moor, 2008 ; Maguire, 2008 ; Molloy & Larner, 2010 ; Brennan & Webster, 2011 ; Foster and al., 2011 ; Scott, 2012 ; Friedman, 2014 ; Griswold & Wohl, 2015 ; Liz\ue9, 2016) consist mainly in the study of people funding artistic activities, \uab gatekeepers \ubb, distributors, and all kind of actors that do not directly act on the material form of the artistic object, whereas it is the case of technicians. Nonetheless, isolated works suggest that technician\u2019s roles in musical works is anything but secondary. Edward Kealy (1979) showed how the restructuration of the profession in the US in the sixties heavily contributed to the emergence of the rock aesthetic, in which, among other things, music started to be played live according to what have been recorded in studio, in opposition with the convention of \uab fidelity \ubb in effect before world war 2 (Maisonneuve, 2009). Ethnographic works focusing on musicians (Perrenoud, 2007 ; Rudent, 2008) also mention the leeway of technicians in recording sessions, and suggest a role that is both artistic, social, and technical (see also Horning, 2004 ; Leyshon, 2009). We are currently conducting, as a PhD thesis, a study of sound engineers in musical production in order to define more precisely in what consists technical work in musical worlds. Driving on a series of individual interviews and participant observations, we will present the figure of live sound engineers, technicians that handle the process of amplification during live performances. We will show that their role, like the one of recording sound engineers, is divided between social and technical work. We will also see that a distinction between classical music and popular music clearly exists in the approach of the amplification process. Finally, we will propose to extend the analysis of technical work in art worlds beyond the specific case of music, and we will look for common properties between our sound engineers and other kind of technical positions such as films editors (Le Guern, 2004) or translators (Kuipers, 2015). We will propose the notion of \uab technical intermediaries \ubb to define a larger category of analysis that could describe technical work in art worlds

Technical intermediaries in music production

In 1979, the Sociology of work and occupations journal issued an article of Edward Kealy accounting for the existence of a very strong link between the musician-technician working relationship during music recording, and the kind of aesthetic outcome (Kealy, 1979). For him, the decentralization of the profession lead to the emergence of new forms of collaboration, that beyond supporting the emergence of rock music, paved the way to a revolution in music production : it is in that period that concerts started to be produced in function of recorded music, while the opposite process had been applied since the beginnings of recorded music (Maisonneuve, 2009 ; Tourn\ue8s, 2008). Despite the important implications of such a result, and the existence of theoretical frames accounting for the collective aspects of musical production (Becker, 1984 ; Peterson et Anand, 2004), the role of technicians in the creative process in music stays marginally studied (see Horning, 2004 ; Leyshon, 2009 ; Le Guern, 2004). One reason might be that their role is quite difficult to conceptualize : they are neither artists, neither audiences, neither gatekeepers and not really cultural intermediaries. To characterize their role in the creative process, we propose to conceptualize them as technical intermediaries. They are close to cultural intermediaries in the sense that they are implied in the framing of goods, carry a specific expertise, and have an impact in the production process (Smith Maguire, 2008). But on the contrary of many studied cases of cultural intermediaries (Franssen & Kuipers, 2013 ; Moor, 2008) they may appear less involved in marketing concerns, and their mediation is more situated between the actors of the production process, rather than between the artists and the audience. With this conceptual toolkit, we are currently conducting an empirical study designed to expand the findings of Kealy to the contemporary context of France and the Netherlands. Using ethnographic methods (interviews and participant observation), we will study two groups of sound engineers in Paris and Amsterdam, tracing their careers, social properties, and working relationships. We will try to understand how the role of technical intermediaries in music production can vary with symbolic boundaries such as music genre and musical aesthetics (Lamont & Th\ue9venot, 2000), as well as with social boundaries such as the presence of absence of a protective social security system (such as the \u201cintermittence\u201d system in France (Menger, 2011)) or the level of common social properties in actors of the production nexus. This study intends to 1. understand the current musician-technicians modes of collaboration and their links to contemporary musical aesthetics, 2. understand how social protection systems and social composition of art worlds influence working practices, and 3. build a conceptual category that would properly describe the role of technicians in cultural production. The first results issued from the fieldwork will be presented

Cultural sociology as a tool for art policies

During the last decades, the discipline of cultural sociology has produced a considerable amount of knowledge on cultural production. Institutional approaches, notably inspired by DiMaggio and Powell (1982) classical article, have notably given the production of culture perspective (Peterson and Anand, 2004). Field analysis (Bourdieu, 1979) have inspired many works that have enlighted the link between social boundaries (Lamont and Molnar, 2002) of cultural practices. Symbolic interactionism, best represented by Howard Becker art worlds (1982) explored the different modes of collaboration between actors and have highlighten the collective aspect of artistic production. Finally, study of mediations have highlighten the role of artworks in constructing social life (Hennion, 1993 ; DeNora, 2000). All these theoretical fields of study have produced a considerable empirical knowledge of different artistic fields, in different countries, both at the level of production and consumption. At the same time, cultural policies seems to take a more and more important position in political life. The best exemple of this might be the dynamism around the 2005 UNESCO convention on the promotion and protection of the diversity of cultural expressions. This convention is used, for instance, by State Parties to inspire cultural policies that they want to develop. It is also used as a platform of exchange of good practices, that it tries to define through directives. For instance, the last Conference of Parties has stated that net neutrality was necessary to cultural diversity. However, the knowledge produced by cultural sociology, mainly through qualitative methods, is curiously absent of the debates of the organization, that produces reports mainly based on quantitative approaches, and make little or no reference to the corpus we have enunciated. This absence can also be found in different states. In our presentation, we will explore some of the possible ways in which the theoretical and empirical knowledge produced in cultural sociology can practically inform arts policies and provide useful practical tools for their conception

Evolution and management of the ligneous vegetation during the neolithic: chacoal analysis of two sheepfold caves in Provence (south of France) : (Pendimoun & Perthus II, France)

International audienc