Contribution à l'étude du rayonnement acoustique des obstacles de révolution, en incidence quelconque, à basse fréquence

Contribution à l'étude du rayonnement acoustique des obstacles de révolution, en incidence quelconque, à basse fréquence PDF Author: Saadia Tallal Rifai
Publisher:
ISBN:
Category :
Languages : fr
Pages : 153

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Book Description
CE TRAVAIL EST UNE CONTRIBUTION A L'ETUDE DU RAYONNEMENT ACOUSTIQUE DES OBSTACLES DE REVOLUTION EN INCIDENCE QUELCONQUE ET A BASSE FREQUENCE. LA PREMIERE PARTIE DECRIT NOTRE ETUDE EXPERIMENTALE DES EFFETS DE DIFFRACTION SUR LA MESURE DE L'INTENSITE ACOUSTIQUE. CETTE ETUDE CONFIRME QUE L'INFLUENCE DE LA DIFFRACTION PEUT ETRE PRISE EN COMPTE EN REMPLACANT DANS L'EXPRESSION DE L'INTENSITE ACOUSTIQUE, LA SEPARATION GEOMETRIQUE PAR UNE SEPARATION APPARENTE. DANS UN DEUXIEME TEMPS, A PARTIR DE CONFIGURATIONS GEOMETRIQUES DONT LES SOLUTIONS EXACTES SONT CONNUES, NOUS CALCULONS LES CARACTERISTIQUES PROPRES A L'ONDE RAYONNEE ET SOULIGNONS LES RAISOS POUR LESQUELLES CETTE SEPARATION GEOMETRIQUE DOIT ETRE REMPLACEE PAR UNE SEPARATION APPARENTE. PUIS, AUX BASSES FREQUENCES, EN INCIDENCE QUELCONQUE ET POUR UN OBSTACLE A SYMETRIE DE REVOLUTION AUTOUR D'UN AXE, NOUS ETABLISSONS LA VALEUR DE LA PRESSION RAYONNEE SUR LA SURFACE DE L'OBSTACLE, AVEC UNE DEPENDANCE EXPLICITE EN (ANGLE D'INCIDENCE) ET (ANGLE POLIARE CLASSIQUE). LA RESOLUTION NUMERIQUE COMPLETE CONSISTE, AUX BASSES FREQUENCES, EN LA RESOLUTION D'UN NOMBRE FINI D'EQUATIONS INTEGRALES SUR UN DOMAINE UNIDIMENSIONNEL. LES RESULTATS NUMERIQUES, DANS LE CAS D'UN CYLINDRE DE LONGUEUR FINIE, SONT COMPARES AUX RESULTATS EXACTS D'UNE FORME GEOMETRIQUE VOISINE, LE SPHEROIDE

Contribution à l'étude du rayonnement acoustique des obstacles de révolution, en incidence quelconque, à basse fréquence

Contribution à l'étude du rayonnement acoustique des obstacles de révolution, en incidence quelconque, à basse fréquence PDF Author: Saadia Tallal Rifai
Publisher:
ISBN:
Category :
Languages : fr
Pages : 153

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Book Description
CE TRAVAIL EST UNE CONTRIBUTION A L'ETUDE DU RAYONNEMENT ACOUSTIQUE DES OBSTACLES DE REVOLUTION EN INCIDENCE QUELCONQUE ET A BASSE FREQUENCE. LA PREMIERE PARTIE DECRIT NOTRE ETUDE EXPERIMENTALE DES EFFETS DE DIFFRACTION SUR LA MESURE DE L'INTENSITE ACOUSTIQUE. CETTE ETUDE CONFIRME QUE L'INFLUENCE DE LA DIFFRACTION PEUT ETRE PRISE EN COMPTE EN REMPLACANT DANS L'EXPRESSION DE L'INTENSITE ACOUSTIQUE, LA SEPARATION GEOMETRIQUE PAR UNE SEPARATION APPARENTE. DANS UN DEUXIEME TEMPS, A PARTIR DE CONFIGURATIONS GEOMETRIQUES DONT LES SOLUTIONS EXACTES SONT CONNUES, NOUS CALCULONS LES CARACTERISTIQUES PROPRES A L'ONDE RAYONNEE ET SOULIGNONS LES RAISOS POUR LESQUELLES CETTE SEPARATION GEOMETRIQUE DOIT ETRE REMPLACEE PAR UNE SEPARATION APPARENTE. PUIS, AUX BASSES FREQUENCES, EN INCIDENCE QUELCONQUE ET POUR UN OBSTACLE A SYMETRIE DE REVOLUTION AUTOUR D'UN AXE, NOUS ETABLISSONS LA VALEUR DE LA PRESSION RAYONNEE SUR LA SURFACE DE L'OBSTACLE, AVEC UNE DEPENDANCE EXPLICITE EN (ANGLE D'INCIDENCE) ET (ANGLE POLIARE CLASSIQUE). LA RESOLUTION NUMERIQUE COMPLETE CONSISTE, AUX BASSES FREQUENCES, EN LA RESOLUTION D'UN NOMBRE FINI D'EQUATIONS INTEGRALES SUR UN DOMAINE UNIDIMENSIONNEL. LES RESULTATS NUMERIQUES, DANS LE CAS D'UN CYLINDRE DE LONGUEUR FINIE, SONT COMPARES AUX RESULTATS EXACTS D'UNE FORME GEOMETRIQUE VOISINE, LE SPHEROIDE

Etude du rayonnement acoustique des obstacles de révolution

Etude du rayonnement acoustique des obstacles de révolution PDF Author: Saadia Tallal Epouse Rifai
Publisher: Editions Universitaires Europeennes
ISBN: 9783841797322
Category :
Languages : fr
Pages : 176

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Book Description
La premiere partie decrit l'etude experimentale des effets de diffraction sur la mesure de l'intensite acoustique. Cette etude confirme que l'influence de la diffraction peut etre prise en compte en remplacant, dans l'expression de l'intensite acoustique, la separation geometrique, dx, par une separation apparente, ' app Dans un deuxieme temps, a partir de configurations geometriques dont les solutions exactes sont connues nous calculons les caracteristiques propres a l'onde rayonnee et soulignons les raisons pour lesquelles cette separation geometrique doit etre remplacee par une separation apparente. Puis, aux basses frequences, en incidence quelconque et pour un obstacle a symetrie de revolution autour d'un axe, nous etablissons la valeur de la pression rayonnee sur la surface de l'obstacle, avec une dependance explicite en a (angle d'incidence) et 9 (angle polaire classique). La resolution numerique complete consiste, aux basses frequences, en la resolution d'un nombre fini d'equations integrales sur un domaine unidimensionnel. Les resultats numeriques, dans le cas d'un cylindre de longueur finie, sont compares aux resultats exacts d'une forme geometrique voisine, le spheroide."

ETUDE DU RAYONNEMENT ACOUSTIQUE D'UN OBSTACLE CYLINDRIQUE PLACE DANS UN ECOULEMENT D'AIR SUBSONIQUE

ETUDE DU RAYONNEMENT ACOUSTIQUE D'UN OBSTACLE CYLINDRIQUE PLACE DANS UN ECOULEMENT D'AIR SUBSONIQUE PDF Author: SAID.. RIFAI
Publisher:
ISBN:
Category :
Languages : fr
Pages :

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Book Description
ON ETUDIE LE RAYONNEMENT ACOUSTIQUE ENGENDRE PAR UN ECOULEMENT SUBSONIQUE AUTOUR DE CYLINDRES DE SECTION CIRCULAIRE. DANS UNE PREMIERE PARTIE, DES METHODES DE MESURE BIDIMENSIONNELLES DE L'INTENSITE ACOUSTIQUE SONT UTILISEES POUR CARACTERISER LE CHAMP SONORE DU A UN CYLINDRE ISOLE, A SURFACE LISSE OU A RUGOSITE FINE ALEATOIRE. LA SECONDE PARTIE EST UNE DETERMINATION EXPERIMENTALE DES PRESSIONS PARIETALES SUR UN OU DEUX CYLINDRES CONSIDERES COMME DES MAQUETTES DE CABLES DE TRANSPORT ELECTRIQUE, ET AYANT EN CONSEQUENCE UNE STRUCTURE DE SURFACE A RUGOSITE FORTE ET PERIODIQUE. LES LOIS DE COHERENCE DANS UNE SECTION OU EN ENVERGURE, AINSI QUE LES FONCTIONS DE REPONSE EN FREQUENCE DES PRESSIONS INSTATIONNAIRES ENTRE LES DEUX CYLINDRES SONT DONNEES. DANS LA TROISIEME PARTIE EST PROPOSE UN MODELE NUMERIQUE PLAN DE RAYONNEMENT ACOUSTIQUE D'UN ENSEMBLE DE MONOPOLES PLACES DANS CE PLAN. EN INTRODUISANT LES PARAMETRES ISSUS DES EXPERIENCES CI-DESSUS, UN MODELE DE CALCUL DU BRUIT DU, A UN OU DEUX CABLES DE TRANSPORT ELECTRIQUES PLACES L'UN DERRIERE L'AUTRE, EST ENFIN PRESENTE

Uranie

Uranie PDF Author: Camille Flammarion
Publisher:
ISBN: 9781072589648
Category :
Languages : en
Pages : 188

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Book Description
Nicolas Camille Flammarion FRAS was a French astronomer and author. He was a prolific author of more than fifty titles, including popular science works about astronomy, several notable early science fiction novels, and works on psychical research and related topics.

Quantum Mechanics, Volume 3

Quantum Mechanics, Volume 3 PDF Author: Claude Cohen-Tannoudji
Publisher: John Wiley & Sons
ISBN: 3527345558
Category : Science
Languages : en
Pages : 790

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Book Description
This new, third volume of Cohen-Tannoudji's groundbreaking textbook covers advanced topics of quantum mechanics such as uncorrelated and correlated identical particles, the quantum theory of the electromagnetic field, absorption, emission and scattering of photons by atoms, and quantum entanglement. Written in a didactically unrivalled manner, the textbook explains the fundamental concepts in seven chapters which are elaborated in accompanying complements that provide more detailed discussions, examples and applications. * Completing the success story: the third and final volume of the quantum mechanics textbook written by 1997 Nobel laureate Claude Cohen-Tannoudji and his colleagues Bernard Diu and Franck Laloë * As easily comprehensible as possible: all steps of the physical background and its mathematical representation are spelled out explicitly * Comprehensive: in addition to the fundamentals themselves, the books comes with a wealth of elaborately explained examples and applications Claude Cohen-Tannoudji was a researcher at the Kastler-Brossel laboratory of the Ecole Normale Supérieure in Paris where he also studied and received his PhD in 1962. In 1973 he became Professor of atomic and molecular physics at the Collège des France. His main research interests were optical pumping, quantum optics and atom-photon interactions. In 1997, Claude Cohen-Tannoudji, together with Steven Chu and William D. Phillips, was awarded the Nobel Prize in Physics for his research on laser cooling and trapping of neutral atoms. Bernard Diu was Professor at the Denis Diderot University (Paris VII). He was engaged in research at the Laboratory of Theoretical Physics and High Energy where his focus was on strong interactions physics and statistical mechanics. Franck Laloë was a researcher at the Kastler-Brossel laboratory of the Ecole Normale Supérieure in Paris. His first assignment was with the University of Paris VI before he was appointed to the CNRS, the French National Research Center. His research was focused on optical pumping, statistical mechanics of quantum gases, musical acoustics and the foundations of quantum mechanics.

Safeguarding Traditional Cultures

Safeguarding Traditional Cultures PDF Author: Peter Seitel
Publisher:
ISBN: 9780966552010
Category : Biens culturels - Politique gouvernementale - Congrès
Languages : en
Pages : 399

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Book Description
Proceedings from a conference "A global assessment of the 1989 recommendation on the safeguarding of traditional culture and folklore" held at the Smithsonian Institution June 27-30 1999. The purpose of the conference was to assess the implementation of the Recommendation (an international normative instrument adopted by UNESCO in 1989), to bring together points of view and perspectives on the Recommendaion from around the world, and suggest ways in which the Recommendation might develop in the future so that its purpose, the safeguarding of traditional culture and folklore, might be achieved.

Space Antenna Handbook

Space Antenna Handbook PDF Author: William A. Imbriale
Publisher: John Wiley & Sons
ISBN: 1119993199
Category : Technology & Engineering
Languages : en
Pages : 772

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Book Description
This book addresses a broad range of topics on antennas for space applications. First, it introduces the fundamental methodologies of space antenna design, modelling and analysis as well as the state-of-the-art and anticipated future technological developments. Each of the topics discussed are specialized and contextualized to the space sector. Furthermore, case studies are also provided to demonstrate the design and implementation of antennas in actual applications. Second, the authors present a detailed review of antenna designs for some popular applications such as satellite communications, space-borne synthetic aperture radar (SAR), Global Navigation Satellite Systems (GNSS) receivers, science instruments, radio astronomy, small satellites, and deep-space applications. Finally it presents the reader with a comprehensive path from space antenna development basics to specific individual applications. Key Features: Presents a detailed review of antenna designs for applications such as satellite communications, space-borne SAR, GNSS receivers, science instruments, small satellites, radio astronomy, deep-space applications Addresses the space antenna development from different angles, including electromagnetic, thermal and mechanical design strategies required for space qualification Includes numerous case studies to demonstrate how to design and implement antennas in practical scenarios Offers both an introduction for students in the field and an in-depth reference for antenna engineers who develop space antennas This book serves as an excellent reference for researchers, professionals and graduate students in the fields of antennas and propagation, electromagnetics, RF/microwave/millimetrewave systems, satellite communications, radars, satellite remote sensing, satellite navigation and spacecraft system engineering, It also aids engineers technical managers and professionals working on antenna and RF designs. Marketing and business people in satellites, wireless, and electronics area who want to acquire a basic understanding of the technology will also find this book of interest.

Dictionary of Building and Civil Engineering

Dictionary of Building and Civil Engineering PDF Author: Don Montague
Publisher: Taylor & Francis
ISBN: 9780419199106
Category : Architecture
Languages : en
Pages : 472

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Book Description
This dual-language dictionary lists over 20,000 specialist terms in both French and English, covering architecture, building, engineering and property terms. It meets the needs of all building professionals working on projects overseas. It has been comprehensively researched and compiled to provide an invaluable reference source in an increasingly European marketplace.

Dictionary of French and English, English and French

Dictionary of French and English, English and French PDF Author: John Bellows
Publisher: Legare Street Press
ISBN: 9781017748307
Category :
Languages : en
Pages : 0

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Book Description
This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work is in the "public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.

An Introduction to Differential Manifolds

An Introduction to Differential Manifolds PDF Author: Jacques Lafontaine
Publisher: Springer
ISBN: 3319207350
Category : Mathematics
Languages : en
Pages : 408

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Book Description
This book is an introduction to differential manifolds. It gives solid preliminaries for more advanced topics: Riemannian manifolds, differential topology, Lie theory. It presupposes little background: the reader is only expected to master basic differential calculus, and a little point-set topology. The book covers the main topics of differential geometry: manifolds, tangent space, vector fields, differential forms, Lie groups, and a few more sophisticated topics such as de Rham cohomology, degree theory and the Gauss-Bonnet theorem for surfaces. Its ambition is to give solid foundations. In particular, the introduction of “abstract” notions such as manifolds or differential forms is motivated via questions and examples from mathematics or theoretical physics. More than 150 exercises, some of them easy and classical, some others more sophisticated, will help the beginner as well as the more expert reader. Solutions are provided for most of them. The book should be of interest to various readers: undergraduate and graduate students for a first contact to differential manifolds, mathematicians from other fields and physicists who wish to acquire some feeling about this beautiful theory. The original French text Introduction aux variétés différentielles has been a best-seller in its category in France for many years. Jacques Lafontaine was successively assistant Professor at Paris Diderot University and Professor at the University of Montpellier, where he is presently emeritus. His main research interests are Riemannian and pseudo-Riemannian geometry, including some aspects of mathematical relativity. Besides his personal research articles, he was involved in several textbooks and research monographs.