Download or read book ETUDE MICROSTRUCTURALE FINE DE REVETEMENTS CERAMIQUES DE TYPE BARRIERE THERMIQUE INCIDENTS SUR LA RESISTANCE THERMOMECANIQUE DE CES REVETEMENTS written by Laurent Lelait and published by . This book was released on 1991 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: DANS CETTE ETUDE LA STRUCTURE DE REVETEMENTS DE TYPE BARRIERE THERMIQUE EN ZIRCONE-YTTRIEE A ETE ETUDIEE A UNE ECHELLE MICROSCOPIQUE FINE. IL A ETE MONTRE QUE CERTAINS DEPOTS DE ZIRCONE STABILISEE PAR 8% D'YTTRINE PRESENTENT DIVERS TYPES DE DEFAUTS (MACLAGE ET PSEUDO-APB) DE MEME QUE L'APPARITION PRECIPITES COHERENTS LORS DE RECUITS A HAUTE TEMPERATURE. CHACUNE DE CES MICROSTRUCTURES EST A MEME DE DISSIPER UNE PARTIE DE L'ENERGIE DE PROPAGATION DE FISSURE, PAR UN MECANISME DE DEVIATION. C'EST PROBABLEMENT POURQUOI UN PIC DE RESISTANCE THERMOMECANIQUE EST OBSERVE DANS LE SYSTEME ZIRCONE YTTRINE, POUR LA COMPOSITION INTERMEDIAIRE DE 6-8% EN MASSE D'Y#2O#3. D'AUTRE PART, LA MICROSTRUCTURE DES COUCHES D'OXYDES FORMES A 1100C ET 1200C A L'INTERFACE ZIRCONE/NICRALY DES BARRIERES THERMIQUES A EGALEMENT ETE ETUDIE. LA MORPHOLOGIE DES GRAINS D'ALUMINE EST TYPIQUE D'UNE CROISSANCE A L'INTERFACE METAL/OXYDE. ELLE EST PAR AILLEURS COMPARABLE A CELLE DES COUCHES D'ALUMINE FORMEES SUR DES ALLIAGES NICRALY NUS. UNE SEGREGATION D'YTTRIUM AUX JOINTS DE GRAINS DE L'ALUMINE A ETE OBSERVEE. CES DEUX OBSERVATIONS SUGGERENT QUE LA COUCHE D'ALUMINE S'EST FORMEE PRINCIPALEMENT PAR UNE DIFFUSION DE L'OXYGENE AUX JOINTS DE GRAINS (ACCELEREE PAR LA PRESENCE DE L'YTTRIUM). UN POURCENTAGE SIGNIFICATIF DE ZIRCONIUM A ETE DETECTE DANS LES GRAINS D'ALUMINE; IL SEMBLE QU'UNE PARTIE DE LA COUCHE D'OXYDE SE SOIT FORMEE PAR REDUCTION DU DEPOT DE ZIRCONE. LA GRANDE QUANTITE DE DEFAUTS OBSERVEE DANS LA COUCHE D'ALUMINE FORMEE A 1200C, PROUVE QUE DANS CES CONDITIONS IL EST POSSIBLE D'AVOIR UNE PLASTICITE DE L'ALUMINE DOPEE PAR L'YTTRIUM, LE ZIRCONIUM ET LE CHROME

Download or read book Etude microstructurale fine de rev tements c ramiques de type barri re thermique written by Laurent Lelait and published by . This book was released on 1992 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Government Reports Annual Index written by and published by . This book was released on 1994 with total page 1442 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sections 1-2. Keyword Index.--Section 3. Personal author index.--Section 4. Corporate author index.-- Section 5. Contract/grant number index, NTIS order/report number index 1-E.--Section 6. NTIS order/report number index F-Z.

Download or read book Government Reports Announcements Index written by and published by . This book was released on 1993-12 with total page 688 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Rev tements c ramiques r fractaires r sistance accrue l oxydation written by Anne-Sophie Andreani and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pour améliorer la durée de vie des matériaux à haute température et sous atmosphère oxydante, une solution est l'utilisation d'une protection de surface constituée de matériaux ultra réfractaires non oxydes. Un des objectifs principaux de cette thèse est la sélection et la validation expérimentale de nouvelles compositions chimiques de revêtements utilisés en condition oxydante et corrosive à ultra haute température. Les recherches s'appuient sur une démarche expérimentale physico-chimique se basant sur une approche thermodynamique et thermochimique menée au préalable pour choisir les composés. Les revêtements doivent être stables chimiquement, compatibles thermomécaniquement avec le substrat et adhérent de la température ambiante à celle d'utilisation. De plus, Ils doivent jouer le rôle de barrière environnementale et/ou de barrière thermique.Des tests d'oxydation sont réalisés au four solaire sur les systèmes de matériaux non oxydes massifs élaborés par frittage flash. En parallèle, des composites modèles constitués d'une fibre de carbone revêtue par PVD d'un revêtement métallique ultra réfractaire ont été élaborés puis chauffés par effet Joule afin de réaliser des tests d'oxydation. La compréhension des mécanismes entrant en jeu lors de l'oxydation de ces « nouveaux » revêtements est aussi un des challenges de ce manuscrit. Par ailleurs, elle aide à la classification de ces matériaux selon leur résistance à l'oxydation.

Download or read book ETUDE DE LA CONDUCTIVITE THERMIQUE DE REVETEMENTS CERAMIQUES A BASE DE ZIRCONE RELATION AVEC LA COMPOSITION LA MICROSTRUCTURE ET LA MORPHOLOGIE written by Martine Poulain and published by . This book was released on 1999 with total page 313 pages. Available in PDF, EPUB and Kindle. Book excerpt: LA CONDUCTIVITE THERMIQUE D'UNE BARRIERE THERMIQUE CONSTITUEE D'UN DEPOT DE ZIRCONE YTTRIEE ELABORE PAR PROJECTION PLASMA DEPEND DE : - LA CONDUCTIVITE THERMIQUE DE LA MATRICE CERAMIQUE - LA CONDUCTIVITE THERMIQUE DU GAZ PRESENT DANS LES PORES ET LES MICROFISSURES - L'ARRANGEMENT TRIDIMENSIONNEL DE CES DEUX CONSTITUANTS. A PARTIR DE MESURES DE DIFFUSIVITE PAR MICROSCOPIE PHOTOTHERMIQUE INFRAROUGE SUR DES MONOCRISTAUX DE ZR 1 - XY XO 2 - X / 2, NOUS PROPOSONS UN MODELE EXPLIQUANT LA DECROISSANCE DE LA CONDUCTIVITE THERMIQUE DE LA MATRICE EN FONCTION DE LA TENEUR EN DEFAUTS PONCTUELS (0X

Download or read book Properties of UO2 written by J. Belle and published by . This book was released on 1957 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book In Vessel Melt Retention and Ex Vessel Corium Cooling IAEA Tecdoc No 1906 written by International Atomic Energy Agency and published by International Atomic Energy Agency. This book was released on 2020-08-06 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: This publication results from a technical meeting on phenomenology and technologies relevant to in-vessel melt retention (IVMR) and ex-vessel corium cooling (EVCC). The purpose of the publication is to capture the state of knowledge, at the time of that meeting, related to phenomenology and technologies as well as the challenges and pending issues relevant to IVMR and EVCC for water cooled reactors by summarizing the information provided by the meeting participants in a form useful to practitioners in Member States.

Download or read book Satellite Situation Report written by Goddard Space Flight Center. Office of Public Affairs and published by . This book was released on 1977 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Flexoelectricity in Liquid Crystals written by Agnes Buka and published by World Scientific. This book was released on 2013 with total page 299 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book intends to give a state-of-the-art overview of flexoelectricity, a linear physical coupling between mechanical (orientational) deformations and electric polarization, which is specific to systems with orientational order, such as liquid crystals. Chapters written by experts in the field shed light on theoretical as well as experimental aspects of research carried out since the discovery of flexoelectricity. Besides a common macroscopic (continuum) description the microscopic theory of flexoelectricity is also addressed. Electro-optic effects due to or modified by flexoelectricity as well as various (direct and indirect) measurement methods are discussed. Special emphasis is given to the role of flexoelectricity in pattern-forming instabilities. While the main focus of the book lies in flexoelectricity in nematic liquid crystals, peculiarities of other mesophases (bent-core systems, cholesterics, and smectics) are also reviewed. Flexoelectricity has relevance to biological (living) systems and can also offer possibilities for technical applications. The basics of these two interdisciplinary fields are also summarized.

Download or read book Space Debris written by Heiner Klinkrad and published by Springer Science & Business Media. This book was released on 2006-09-01 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt: The future evolution of the debris environment will be forecast on the basis of traffic models and possible hazard mitigation practices. The text shows how large trackable objects will have re-entry pinpointed and predictions made on related risk assessment for possible ground impact. Models will also be described for meteoroids which are also a prevailing risk.

Download or read book Nonlinear Optical Materials written by Jerome V. Moloney and published by Springer Science & Business Media. This book was released on 1998-08-13 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mathematical methods play a significant role in the rapidly growing field of nonlinear optical materials. This volume discusses a number of successful or promising contributions. The overall theme of this volume is twofold: (1) the challenges faced in computing and optimizing nonlinear optical material properties; and (2) the exploitation of these properties in important areas of application. These include the design of optical amplifiers and lasers, as well as novel optical switches. Research topics in this volume include how to exploit the magnetooptic effect, how to work with the nonlinear optical response of materials, how to predict laser-induced breakdown in efficient optical devices, and how to handle electron cloud distortion in femtosecond processes.