Download or read book Mod lisation de l interaction des coeurs de dislocations et des joints de grains written by Kodjovi Gbemou and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Durant cette thèse, on s'intéresse à l'application et au développement d'une théorie de mécanique des champs de dislocations et de désinclinaisons pour modéliser de façon continue les structures de cœur des dislocations et des joints de grains ainsi que leurs interactions. Le vecteur de Burgers/Frank des dislocations/désinclinaisons est régularisé par l'introduction d'un tenseur densité de dislocations/désinclinaisons. A ces densités de défauts sont associées des déformations et des courbures élastiques et plastiques incompatibles responsables de champs de contraintes et de moments de contraintes internes. Le mouvement des défauts produit de la plasticité et est pris en compte par des équations de transport qui font intervenir des forces motrices agissant sur les densités de défauts. Dans un premier temps, les désinclinaisons sont ignorées et nous appliquons la théorie de champ de dislocations seule pour étudier les structures de cœur de dislocations planaires en comparaison avec le modèle de Peierls-Nabarro. La relaxation d'une structure de cœur de dislocation coin initiale arbitraire révèle un étalement infini des densités de dislocations sous l'action de leur propre champ de contrainte interne. Pour stopper cette relaxation infinie, nous proposons d'ajouter une énergie de misfit dans notre modèle. Cette dernière donne lieu à une contrainte de rappel qui s'oppose à l'étalement des cœurs de dislocations et permet d'obtenir des configurations équilibrées. On retrouve la solution de Peierls-Nabarro si on utilise un potentiel sinusoïdal pour l'énergie. Nous substituons ensuite ce potentiel par des énergies de fautes d'empilement généralisées obtenues à partir de simulations atomistiques pour modéliser la dissociation des dislocations et leur mouvement dans le zirconium et le titane. Dans un deuxième temps, nous considérons la théorie complète et nous développons des lois d'élasticité constitutives qui sont propres aux défauts cristallins. Nous proposons qu'en plus des tenseurs élastiques habituels, des tenseurs d'élasticité additionnels existent au niveau du cœur des défauts et relient respectivement les contraintes aux courbures et les moments de contraintes aux déformations. Ces tenseurs sont de nature non locale par définition à cause des relations cinématiques entre déformations et courbures. Ils sont non nuls au niveau des cœurs des défauts où les hétérogénéités de déformations et de courbures sont fortes et deviennent nuls loin des défauts par centrosymétrie. On applique ces nouvelles lois d'élasticité à des distributions de dislocations et de désinclinaisons. On montre que les termes non locaux donnent lieu à des contraintes/moments de contraintes de rappel qui s'opposent aux parties locales. Dans le cas de la dislocation coin, on montre que sa représentation avec un dipôle de désinclinaison coin permet d'obtenir une configuration équilibrée sans l'ajout d'énergie de misfit. On étudie ensuite les interactions élastiques entre dislocations et joints de grains.

Download or read book Int raction dislocations de matrice joints de grains dans le fer written by Omar Khalfallah and published by . This book was released on 1988 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: ANALYSE THEORIQUE PAR LE CALCUL DE LA FORCE IMAGE ET EXPERIMENTALE PAR MICROSCOPIE ELECTRONIQUE EN TRANSMISSION DE L'INTERACTION D'UNE DISLOCATION AVEC UN JOINT DE GRAINS. CALCUL SUR LA BASE DE L'ELASTICITE ANISOTROPE DE L'ENERGIE DONT DERIVE LA FORCE IMAGE POUR DIFFERENTES SITUATIONS CRISTALLOGRAPHIQUES. LES FAIBLES INTERACTIONS SONT ASSOCIEES AUX CONFIGURATIONS DE HAUTE SYMETRIE. LA FORCE IMAGE PEUT AGIR SUR UNE DISLOCATION JUSQU'A UNE DISTANCE DE L'ORDRE DE 100NM. LES SITUATIONS DE NON INCORPORATION DE LA DISLOCATION DE MATRICE AU JOINT S'EXPLIQUENT PAR L'INTERVENTION DES PARAMETRES CRISTALLOGRAPHIQUES.

Download or read book Interaction dislocations joints de grains dans le germanium written by Henri-Marc Michaud and published by . This book was released on 1991 with total page 370 pages. Available in PDF, EPUB and Kindle. Book excerpt: L'INTERACTION DISLOCATIONS JOINTS DE GRAINS EST ETUDIEE A PARTIR DE BICRISTAUX DE GERMANIUM CORRESPONDANT MAUX MACLES D'INDICES DE COINCIDENCE DIX NEUF ET CINQUANTE ET UN. LA STRUCTURE ATOMIQUE DE CES INTERFACES EST DETERMINEE PAR MICROSCOPIE ELECTRONIQUE A HAUTE RESOLUTION. LA MEME TECHNIQUE EST UTILISEE POUR REPERTORIER LES DEFAUTS INTERGRANULAIRES RESULTANT DE LA DEFORMATION DU BICRISTAL. LA STRUCTURE DES DEFAUTS LES PLUS SIMPLES EST DETERMINEE ET LEUR HISTORIQUE EST RETRACE DANS LA PLUPART DES CAS. LA DEFORMATION IN SITU DANS UN MICROSCOPE ELECTRONIQUE PERMET DE METTRE CLAIREMENT EN EVIDENCE LE FRANCHISSEMENT DE L'INTERFACE EN TETE D'EMPILEMENT. CONCERNANT LA MACLE D'INDICE DE COINCIDENCE CINQUANTE ET UN, L'INVERSION DE L'ORDRE DES DISLOCATIONS PARTIELLES DE SCHOCKLEY REVELE L'INFLUENCE DE CELUI-CI SUR LE PROCESSUS DE LA TRANSMISSION. UNE EXPERIENCE COMBINANT L'EXPERIMENTATION IN SITU SUIVIE D'OBSERVATIONS EN MICROSCOPIE A HAUTE RESOLUTION A PERMIS DE METTRE EN EVIDENCE DEUX CAS DE DECOMPOSITION DE DISLOCATIONS DE MATRICE EN SOUS-PRODUITS INTERGRANULAIRES. CERTAINS D'ENTRE EUX SONT MOBILES DANS L'INTERFACE PAR GLISSEMENT PUR ALORS QUE D'AUTRES SE DEPLACENT DANS LE JOINT DE GRAINS PAR GLISSEMENT ET MONTEE. UN MODELE EST PROPOSE POUR INTERPRETER LES DIFFERENTS PHENOMENES OBSERVES. IL REPOSE SUR L'HYPOTHESE D'UNE INTERACTION PARTIELLE APRES PARTIELLE ET SUR LE CALCUL DE L'ENERGIE ELASTIQUE ASSOCIE A CHACUN DES DEFAUTS. POUR CHAQUE ETAPE DU PROCESSUS DE L'INTERACTION DISLOCATIONS-JOINTS DE GRAINS, IL PERMET DE SELECTIONNER LES CHEMINS LES PLUS PROBABLES

Download or read book Materials Issues for Generation IV Systems written by Véronique Ghetta and published by Springer Science & Business Media. This book was released on 2008-04-23 with total page 596 pages. Available in PDF, EPUB and Kindle. Book excerpt: Global warming, shortage of low-cost oil resources and the increasing demand for energy are currently controlling the world's economic expansion while often opposing desires for sustainable and peaceful development. In this context, atomic energy satisfactorily fulfills the criteria of low carbon gas production and high overall yield. However, in the absence of industrial fast-breeders the use of nuclear fuel is not optimal, and the production of high activity waste materials is at a maximum. These are the principal reasons for the development of a new, fourth generation of nuclear reactors, minimizing the undesirable side-effects of current nuclear energy production technology while increasing yields by increasing operation temperatures and opening the way for the industrial production of hydrogen through the decomposition of water. The construction and use of such reactors is hindered by several factors, including performance limitations of known structural materials, particularly if the life of the projected systems had to extend over the periods necessary to achieve low costs (at least 60 years). This book collects lectures and seminars presented at the homonymous NATO ASI held in autumn 2007 at the Institut d’Etudes Scientifiques in Cargèse, France. The adopted approach aims at improving and coordinating basic knowledge in materials science and engineering with specific areas of condensed matter physics, the physics of particle/matter interaction and of radiation damage. It is our belief that this methodology is crucially conditioning the development and the industrial production of new structural materials capable of coping with the requirements of these future reactors.

Download or read book X Ray Charge Densities and Chemical Bonding written by Philip Coppens and published by International Union of Crystallography. This book was released on 1997-05-08 with total page 373 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book deals with the electron density distribution in molecules and solids as obtained experimentally by X-ray diffraction. It is a comprehensive treatment of the methods involved, and the interpretation of the experimental results in terms of chemical bonding and intermolecular interactions. Inorganic and organic solids, as well as metals, are covered in the chapters dealing with specific systems. As a whole, this monograph is especially appealing because of its broad interface with numerous disciplines. Accurate X-ray diffraction intensities contain fundamental information on the charge distribution in crystals, which can be compared directly with theoretical results, and used to derive other physical properties, such as electrostatic moments, the electrostatic potential and lattice energies, which are accessible by spectroscopic and thermodynamic measurements. Consequently, the work will be of great interest to a broad range of crystallographers and physical scientists.

Download or read book Underground Disposal of Radioactive Wastes written by International Atomic Energy Agency and published by . This book was released on 1981 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Metal Forming and the Finite Element Method written by the late Shiro Kobayashi and published by Oxford University Press. This book was released on 1989-03-09 with total page 398 pages. Available in PDF, EPUB and Kindle. Book excerpt: The application of computer-aided design and manufacturing techniques is becoming essential in modern metal-forming technology. Thus process modeling for the determination of deformation mechanics has been a major concern in research . In light of these developments, the finite element method--a technique by which an object is decomposed into pieces and treated as isolated, interacting sections--has steadily assumed increased importance. This volume addresses advances in modern metal-forming technology, computer-aided design and engineering, and the finite element method.

Download or read book X Ray and Neutron Reflectivity Principles and Applications written by Jean Daillant and published by Springer Science & Business Media. This book was released on 2003-07-01 with total page 347 pages. Available in PDF, EPUB and Kindle. Book excerpt: The reflection of and neutrons from surfaces has existed as an x-rays exp- imental for almost it is in the last technique fifty Nevertheless, only years. decade that these methods have become as of enormously popular probes This the surfaces and interfaces. to be due to of several appears convergence of intense different circumstances. These include the more n- availability be measured orders tron and sources that can over (so reflectivity x-ray many of and the much weaker surface diffuse can now also be magnitude scattering of thin films and studied in some the detail); growing importance multil- basic the realization of the ers in both and technology research; important which in the of surfaces and and role roughness plays properties interfaces; the of statistical models to characterize the of finally development topology its and its characterization from on roughness, dependence growth processes The of and to surface scattering experiments. ability x-rays neutro4s study four five orders of in scale of surfaces over to magnitude length regardless their and also their to ability probe environment, temperature, pressure, etc. , makes these the choice for buried interfaces often probes preferred obtaining information about the microstructure of often in statistical a global surfaces, the local This is manner to complementary imaging microscopy techniques, of such studies in the literature witnessed the veritable by explosion published the last few Thus these lectures will useful for over a resource years.

Download or read book Kader Attia written by Kader Attia and published by . This book was released on 2019-02-20 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the rising stars in the international art scene, Kader Attia (b. 1970) is a French-Algerian multidisciplinary artist whose powerful yet complex images, objects and installations examine the way cultures and histories have been constructed.Attia often plays with the vocabulary of museums and architecture to trouble the boundaries between different worlds, particularly Western and non-Western, through his use of re-appropriated and repaired everyday objects and ephemera, such as African masks, stapled paving cracks, assemblages of prostheses and photographs of surgical reconstruction.An in-depth interview with Hayward Gallery director Ralph Rugoff explores the artist's major themes, while art historians and other experts draw out particular threads to examine in depth. Compact but wide-ranging, this is a publication to be held in the hand - an indispensable first guide to an artist with an exceptional perspective on the way humans think about their place in the world.The book features an interview with Ralph Rugoff and essays by Nicola Clayton, Jean-Michel Frodon, Francoise Vergès and Giovanna Zapperi.Published alongside Hayward Gallery's exhibition, London (12 February - 6 May 2019).

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 Manganese in Powder Metallurgy Steels written by Andrej Šalak and published by Springer Science & Business Media. This book was released on 2012-07-13 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work in three parts presents a summary of the sintered manganese steel properties from 1948 to 2011 involving processing conditions and other characteristics. In the first and third part are given results attained by the authors based on their finding that manganese (cheapest element) during sintering evaporates and by this the vapour cleans the sintering atmospheres from humidity. The second part presents other positive properties of manganese steels in spite of the doubt of oxidation of manganese during sintering and by this excluding the sintering manganese steels what hinderd the use of manganese in production of sintered parts. All results confirm that only manganese vapour according to finding of the authors ensures effective sintering of manganese steels and parts independently on the authors mind. It follows finally from the work that manganese is possible to use for alloying of powder steels sintered also in practice in H/N atmospheres with low purity and also in pure nitrogen - cheaper than hydrogen without some of the associated problems. Current trends in the field are also presented to the reader.

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 Landscapes and Landforms of France written by Monique Fort and published by Springer Science & Business Media. This book was released on 2013-08-23 with total page 283 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Landforms and Landscapes of France provides an informative and attractive overview of the most scenic landscapes of France. The geodiversity of France is emphasized, for example the glacial landscapes of the Mont-Blanc Massif, the volcanoes of the French Massif Central, the chalk cliffs and sand dunes of the Atlantic coast, the granitic landscapes of Corsica or the lagoons and coral reefs of French Polynesia. The objectives are to provide the reader with an enjoyable and informative description of the selected sites within their regional geographical and geological settings; to offer an up-to-date survey of the evolution of France's landscape; and to give additional information on the cultural value of the selected sites wherever appropriate (prehistoric paintings, legends related to sites, famous vineyards, etc.). The book is a richly illustrated reference work that makes accessible for the first time a wealth of information currently scattered among many national and regional journals. It will be of benefit to earth scientists, environmental scientists, tourism geographers and conservationists

Download or read book Atlas of Structural Geology written by Soumyajit Mukherjee and published by Elsevier. This book was released on 2015-04-28 with total page 183 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atlas of Structural Geology features a broad and inclusive range of high-quality meso- and micro-scale full-color photographs, descriptions, and captions related to the deformation of rocks and geologic structures. It is a multi-contributed, comprehensive reference that includes submissions from many of the world's leading structural geologists, making it the most thorough and comprehensive reference available to the scientific community. All types of structures are featured, including structures related to ductile and brittle shear zones, sigma- and delta-structures, mineral fish, duplexes and trapezoids, shear related folds, and flanking structures in meso- and micro-scales. A stunning collection of the world's most beautiful and arresting geologic structures, the Atlas of Structural Geology is the ideal aid in the retention of key concepts in geology. - Presents more than 250 top-quality, full-color photographs contributed by the world's most respected structural geologists - Features a broad range of morphological variations of geologic structures, making it the most up-to-date and inclusive reference of its kind - Edited by a structural geologist with 14 years of experience in related research and instruction - Aids researchers in developing mathematical and analogue models on the peculiarity and uniqueness of the world's most iconic structures

Download or read book Fatigue of Materials and Structures written by Claude Bathias and published by John Wiley & Sons. This book was released on 2013-03-04 with total page 415 pages. Available in PDF, EPUB and Kindle. Book excerpt: The design of mechanical structures with improved and predictable durability cannot be achieved without a thorough understanding of the mechanisms of fatigue damage and more specifically the relationships between the microstructure of materials and their fatigue properties. Written by leading experts in the field, this book (which is complementary to Fatigue of Materials and Structures: Application to Damage and Design, also edited by Claude Bathias and André Pineau), provides an authoritative, comprehensive and unified treatment of the mechanics and micromechanisms of fatigue in metals, polymers and composites. Each chapter is devoted to one of the major classes of materials or to different types of fatigue damage, thereby providing overall coverage of the field. The book deals with crack initiation, crack growth, low-cycle fatigue, gigacycle fatigue, shorts cracks, fatigue micromechanisms and the local approach to fatigue damage, corrosion fatigue, environmental effects and variable amplitude loadings, and will be an important and much used reference for students, practicing engineers and researchers studying fracture and fatigue in numerous areas of mechanical, structural, civil, design, nuclear, and aerospace engineering as well as materials science.

Download or read book Multi mechanism Modeling of Inelastic Material Behavior written by Georges Cailletaud and published by John Wiley & Sons. This book was released on 2018-03-13 with total page 293 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on a particular class of models (namely Multi-Mechanism models) and their applications to extensive experimental data base related to different kind of materials. These models (i) are able to describe the main mechanical effects in plasticity, creep, creep/plasticity interaction, ratcheting extra-hardening under non-proportional loading (ii) provide local information (such us local stress/strain fields, damage, ….). A particular attention is paid to the identification process of material parameters. Moreover, finite element implementation of the Multi-Mechanism models is detailed.