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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

??tude et caract??risation du comportement thermom??canique de r??cepteur d'un syst??me photovolta??que concentr??

Chroufa, Mohamed January 2014 (has links)
Le d??veloppement dans la derni??re d??cennie des syst??mes photovolta??ques concentr??s a augment?? le besoin de g??rer le budget thermique dans le r??cepteur pour emp??cher sa surchauffe et g??rer les pertes de performances li??es ?? la temp??rature. Ce projet de ma??trise s'inscrit dans le cadre du d??veloppement d???un syst??me solaire fortement concentr?? en collaboration avec des partenaires industriels. Notre partenaire industriel a mis au point une solution de production d?????nergie photovolta??que de haute concentration ?? l?????chelle commerciale, mais il reste ?? valider la conception du syst??me adopt??. Le projet concerne l'??tude du r??cepteur photovolta??que qui est compos?? d???un r??seau dense de 800 cellules solaires triple jonctions, mont??es sur un substrat. Ce dernier est compos?? d???un empilement de couches et un ??changeur de chaleur pour refroidir le r??cepteur. Puisque notre r??cepteur absorbera un grand flux de chaleur, il y aura des contraintes dues ?? la non-concordance des coefficients de dilatation thermique entre ses diff??rentes couches. Ces d??formations pourraient provoquer la rupture de contact entre les cellules solaires, et ainsi la d??faillance ??lectrique du r??cepteur. Pour cela, ces travaux de recherche ont port?? sur une ??tude thermom??canique du r??cepteur. En effet, l?????tude de la dilatation de l'assemblage multicouche a permis d???acqu??rir une connaissance d???analyse thermom??canique de la tenue de la structure multicouche vis-??-vis d???un chargement thermique. Puis, le comportement des ??poxys, conducteur et isolant ??lectrique utilis??s pour fixer les cellules sur le substrat, a ??t?? ??tudi?? en fonction de plusieurs param??tres g??om??triques et des propri??t??s mat??rielles. La diff??rence des coefficients d???expansion thermiques (CTE) des ??poxys, ??tait le param??tre cl?? pour varier les contraintes dans les interconnexions. Cons??quemment, on a utilis?? deux ??poxys avec deux CTE proches pour diminuer les contraintes induites dans les deux ??poxys. De plus, vu que la structure se compose des couches usin??es, on a cr???? des abaques de variation de rigidit?? effective en fonction des facteurs de formes dimensionnels des couches usin??es. Enfin, le travail a permis de mettre en place des essais exp??rimentaux pour s???assurer du fonctionnement du r??cepteur ?? haute temp??rature. Par cons??quent, on a valid?? l???utilisation de l?????poxy dans la conception adopt??e vu que la d??formation maximale support??e par ce dernier ([epsilon Minuscule][indice inf??rieur m ax]=0.167 %) est sup??rieure ?? la d??formation maximale qu???il peut avoir au cours de l'op??ration ([epsilon Minuscule][indice inf??rieur ??poxy]=0.0048%). Ensuite, les exigences de r??cepteur en termes de fonctionnement ?? haute temp??rature ont ??t?? fix??es, comme l?????cart maximal que l?????poxy peut supporter pour la liaison des cellules entre deux unit??s du r??cepteur qui est [delta Majuscule]Gap[indice inf??rieur limite] [epsilon Minuscule] [[Plus ou moins]46 [mu Minuscule]m, [Plus ou moins]53 [mu Minuscule]m].
2

Yves Daniel-Lesur and le canique des cantiques: nonconformism and humanism in a mid-twentieth-century choral work

Cheng, Chi-Suen 02 August 2016 (has links)
In 1936, André Jolivet (1905-1974), Yves Baudrier (1906-1988), Olivier Messiaen (1908-1992), Jean-Yves Daniel-Lesur (1908-2002), and Pierre Schaeffer (1910-1995) founded the group Jeune France. They initiated this group under the influence of politically nonconformist movements in France which had started in the 1920s. The ideology of Jeune France was to revive in music 'true human qualities', free from 'extreme political domination'. At a time when some composers, associated with a revolutionary Left wing, were exploring avant-garde ideas in music that included atonalism, serialism, and other advanced techniques out of the common practice, other composers fell into a nationalistic Right wing, recalling the French Catholic traditions, and promoting an exclusive and true 'French' music. In contrast to these polarizing trends, Jeune France tried to trace back its art to its origins, and the goal of Jeune France was to re-establish music composition as something less 'abstract' than the Left, and more 'human' than the Right. The most powerful sound that can reflect the tenets of humanism in music is probably the human voice, especially multiple voices in a choral setting. Thus unaccompanied choral works, in particular, came to be a hallmark of many major composers of the 20th Century. The prevailing social and political environment of the pre-World War Two era also played an important role in contributing to the revival of unaccompanied choral music as a major genre. To demonstrate how these general social and political forces operated in the particular in France at this time, I have used Daniel-Lesur's Le Cantique des Cantiques (1952) to show how these affected a composer at this time. The goal of this research has been to look in depth at both Daniel-Lesur and his most famous work, about which little has been written in English; and to add to a growing body of literature which explores the rise of unaccompanied choral compositions as an important genre in the early 20th Century, a shift that is tied to political, cultural, and social conditions as well as musical ones. Taking Le Cantique des Cantiques as a token of a type, I show how this work reflects these issues as well as the aesthetics behind Jeune France. Finally, I have tried to show just how the experience of Jeune France influenced Daniel-Lesur as a composer as it did his more famous contemporary, Messiaen.

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