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Dissertations / Theses on the topic 'Speed of sound wave propagation'

Author: Grafiati

Published: 2 June 2025

Last updated: 31 July 2025

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1

Tombul, Serdar. "A numerical study of the validity regimes of weak fluctuation theory for ocean acoustic propagation through random internal wave sound speed fields." Thesis, Monterey, Calif. : Naval Postgraduate School, 2007. http://bosun.nps.edu/uhtbin/hyperion.exe/07Mar%5FTombul.pdf.

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Thesis (M.S. in Engineering Acoustics and M.S. in Electrical Engineering)--Naval Postgraduate School, March 2007.<br>Thesis Advisor(s): John Colosi. "March 2007." Includes bibliographical references (p. 81-82 ). Also available in print.

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2

Maess, Matthias. "Material characterization using nonlinear wave propagation." Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/19311.

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3

Yildirim, Baran. "Acoustic Wave Analysis Using Different Wave Propagation Models." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12609527/index.pdf.

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In this study in order to simulate the acoustic waves, Ray Theory and Normal Mode models are used. These methods are analyzed using MATLAB simulation tool<br>differences between two models are examined and a region with a known bottom profile and sound velocity profiles is investigated. The Ray Theory is used in acoustic systems which is the one of the applications of wave modeling. Ray theory is solved with standard Ordinary Differential Equation solvers and normal mode with finite element method. Different bottom profiles and sound velocity profiles previously taken are interpolated to form

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4

Berglund, Alexander, Fredrik Herbai, and Jonas Wedén. "Sound Propagation Through Walls." Thesis, Uppsala universitet, Avdelningen för beräkningsvetenskap, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-444632.

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Infrasound is undetectable by the human ear and excessive exposure may be a substantial health risk. Low frequency sound propagates through walls with minimal attenuation, making it difficult to avoid. This study interprets the results from both analytical calculations and simulations of pressure waves propagating through a wall in one dimension. The wall is thin compared to the wavelength; the model implements properties of three materials commonly used in walls. The results indicate that the geometry of the wall, most importantly the small ratio between wall width and wavelength, is the prim

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5

Kappel, Marcel. "Scattering effects in the sound wave propagation of instrument soundboards." Phd thesis, Universität Potsdam, 2012. http://opus.kobv.de/ubp/volltexte/2012/6267/.

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In the western hemisphere, the piano is one of the most important instruments. While its evolution lasted for more than three centuries, and the most important physical aspects have already been investigated, some parts in the characterization of the piano remain not well understood. Considering the pivotal piano soundboard, the effect of ribs mounted on the board exerted on the sound radiation and propagation in particular, is mostly neglected in the literature. The present investigation deals exactly with the sound wave propagation effects that emerge in the presence of an array of equally-d

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6

Hammar, Johan. "A Wave Expansion Method for Aeroacoustic Propagation." Licentiate thesis, KTH, Aerodynamik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-196689.

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Although it is possible to directly solve an entire flow-acoustics problem in one computation, this approach remains prohibitively large in terms of the computational resource required for most practical applications. Aeroacoustic problems are therefore usually split into two parts; one consisting of the source computation and one of the source propagation. Although both these parts entail great challenges on the computational method, in terms of accuracy and efficiency, it is still better than the direct solution alternative. The source usually consists of highly turbulent flows, which for mo

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7

Khalili, Nasser. "Application of Cepstral techniques to the measurement of reflection coefficients for dispersive systems." Thesis, University of Southampton, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303060.

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8

Muhlestein, Michael B. "Analyses of Nonlinearity Measures in High-Amplitude Sound Propagation." BYU ScholarsArchive, 2013. https://scholarsarchive.byu.edu/etd/3994.

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Military aircraft generate high-amplitude noise which can cause injury to attending personnel. Efforts to mitigate the effects of this noise require a detailed understanding of the propagation of the noise, which was shown previously to be nonlinear. This thesis presents an analysis of high-amplitude noise propagation, emphasizing measures used to quantify the importance of considering nonlinearity. Two measures of the importance of nonlinearity are compared. These measures are the wave steepening factor and a skewness estimate. The wave steepening factor is a measure of how much nonlinear wav

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9

Weng, Chenyang. "Theoretical and numerical studies of sound propagation in low-Mach-number duct flows." Doctoral thesis, KTH, MWL Marcus Wallenberg Laboratoriet, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-168031.

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When sound waves propagate in a duct in the presence of turbulent flow, turbulent mixing can cause attenuation of the sound waves extra to that caused by the viscothermal effects. Experiments show that compared to the viscothermal effects, this turbulent absorption becomes the dominant contribution to the sound attenuation at sufficiently low frequencies. The mechanism of this turbulent absorption is attributed to the turbulent stress and the turbulent heat transfer acting on the coherent perturbations (including the sound waves) near the duct wall, i.e. sound-turbulence interaction. The purpo

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10

Fritzell, Julius. "Sound propagation modelling with applications to wind turbines." Thesis, KTH, Mekanik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-260322.

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Wind power is a rapidly increasing resource of electrical power world-wide. With the increasing number of wind turbines installed one major concern is the noise they generate. Sometimes already built wind turbines have to be put down or down-regulated, when certain noise levels are exceeded, resulting in economical and environmental losses. Therefore, accurate sound propagation calculations would be beneficial already in a planning stage of a wind farm. A model that can account for varying wind speeds and complex terrains could therefore be of great importance when future wind farms are planne

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11

Li, Kuo-Hui. "RF beamformers for high-speed wireless communications." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/14768.

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12

Podo, Smardie D. "Comparison of layering effects in the propagation of transient planar stress waves." Thesis, Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/18378.

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13

Voloshin, Vitaly. "Moving load on elastic structures : passage through the wave speed barriers." Thesis, Brunel University, 2010. http://bura.brunel.ac.uk/handle/2438/4614.

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The asymptotic behaviour of an elastically supported infinite string and an elastic isotropic half plane (in frames of specific asymptotic model) under a moving point load are studied. The main results of this work are uniform asymptotic formulae and the asymptotic profile for the string and the exact solution and uniform asymptotic formulae for a half plane. The crucial assumption for both structures is that the acceleration is sufficiently small. In order to describe asymptotically the oscillations of an infinite string auxiliary canonical functions are introduced, asymptotically analyzed an

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14

Kappel, Marcel [Verfasser], and Reimund [Akademischer Betreuer] Gerhard. "Scattering effects in the sound wave propagation of instrument soundboards / Marcel Kappel. Betreuer: Reimund Gerhard." Potsdam : Universitätsbibliothek der Universität Potsdam, 2012. http://d-nb.info/1028121849/34.

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15

Ducret, Fabrice. "Studies of sound generation and propagation in flow ducts." Licentiate thesis, Stockholm : Royal Institute of Technology, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4049.

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16

Clavica, Francesco. "Computational and experimental time domain, one dimensional models of air wave propagation in human airways." Thesis, Brunel University, 2012. http://bura.brunel.ac.uk/handle/2438/9622.

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The scientific literature on airflow in the respiratory system is usually associated with rigid ducts. Many studies have been conducted in the frequency domain to assess respiratory system mechanics. Time-domain analyses appear more independent from the hypotheses of periodicity, required by frequency analysis, providing data that are simpler to interpret since features can be easily associated to time. However, the complexity of the bronchial tree makes 3-D simulations too expensive computationally, limiting the analysis to few generations. 1-D modelling in space-time variables has been exten

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17

Li, Ye. "Propagation and reflection of pulse waves in flexible tubes and relation to wall properties." Thesis, Brunel University, 2011. http://bura.brunel.ac.uk/handle/2438/6554.

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The wall properties of the arteries play an important role in cardiovascular function. Stiffness of large artery is predictive of cardiovascular events. To understand the function of the cardiovascular system, special attention should be paid to the understanding of pulse wave propagation, because pulse waves carry information of the cardiovascular function, and provide information which can be useful for the prevention and diagnosis of diseases. This thesis presents a series of in vitro experimental studies of wave propagation, wave reflection and determination of mechanical properties of fle

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18

Sinha, Moitreyee. "PROBING POLYMER NETWORKS USING PULSE PROPAGATION AND BRILLOUIN LIGHT SCATTERING TECHNIQUES." University of Cincinnati / OhioLINK, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=ucin974213434.

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19

Leissing, Thomas. "Nonlinear acoustic wave propagation in complex media : application to propagation over urban environments." Phd thesis, Université Paris-Est, 2009. http://tel.archives-ouvertes.fr/tel-00584398.

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Dans cette recherche, un modèle de propagation d'ondes de choc sur grandes distances sur un environnement urbain est construit et validé. L'approche consiste à utiliser l'Equation Parabolique Nonlinéaire (NPE) comme base. Ce modèle est ensuite étendu afin de prendre en compte d'autres effets relatifs à la propagation du son en milieu extérieur (surfaces non planes, couches poreuses, etc.). La NPE est résolue en utilisant la méthode des différences finies et donne des résultats en accord avec d'autres méthodes numériques. Ce modèle déterministe est ensuite utilisé comme base pour la constructio

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20

Rodriguez, Herrera Diego. "Antenna characterisation and optimal sampling constraints for breast microwave imaging systems with a novel wave speed propagation algorithm." IEEE, 2014. http://hdl.handle.net/1993/31907.

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Breast microwave imaging (BMI) is a novel modality that complements current breast screening tools. Microwave radar imaging creates a radar cross-section (reflection) map of the breast. The difference in permittivity between healthy and malignant tissue is between 10-50%. This contrast is significantly higher than that obtained with x-rays and supports the use of microwave imaging for breast cancer diagnosis. Prior to widespread clinical use, some areas require further study. Firstly, the performance of three different antennas was carried out, to assess their suitability for a BMI system.

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21

Gamini, G. N. "Adriatic wave propagation in solid and gaseous Hesup(4) : a low temperature study of second sound in solid Hesup(4) and first sound in the gas phase." Thesis, University of Kent, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356565.

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22

Legendre, César. "On the interactions of sound waves and vortices." Doctoral thesis, Universite Libre de Bruxelles, 2015. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209147.

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The effects of vortices on the propagation of acoustic waves are numerous, from simple convection effects to instabilities in the acoustic phenomena, including absorption,<p>reflection and refraction effects. This work focusses on the effects of mean flow<p>vorticity on the acoustic propagation. First, a theoretical background is presented<p>in chapters 2-5. This part contains: (i) the fluid dynamics and thermodynamics<p>relations; (ii) theories of sound generation by turbulent flows; and (iii) operators taken<p>from scientific literature to take into account the vorticity effects on acoustics

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23

Schulz, Sebastian Andreas. "Propagation loss in slow light photonic crystal waveguides." Thesis, University of St Andrews, 2012. http://hdl.handle.net/10023/2837.

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The field of nanophotonics is a major research topic, as it offers potential solutions to important challenges, such as the creation of low power, high bandwidth interconnects or optical sensors. Within this field, resonant structures and slow light waveguides are used to improve device performance further. Photonic crystals are of particular interest, as they allow the fabrication of a wide variety of structures, including high Q-factor cavities and slow light waveguides. The high scattering loss of photonic crystal waveguides, caused by fabrication disorder, however, has so far proven to be

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24

Abi, rizk Lara. "Ondes progressives et propriétés de propagation pour un problème d’épidémiologie évolutive non-local." Thesis, Bordeaux, 2020. http://www.theses.fr/2020BORD0244.

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Dans cette thèse nous étudions l’existence d’une onde progressive pour un système d’équations intégro-différentiels provenant de l’épidémiologie évolutive. Nous utilisons des idées issues de la théorie des systèmes dynamiques couplées à des estimations sur le comportement asymptotique des profils. Nous prouvons que les ondes progressives ont une structure assez simple découplant les variables de propagation spatio-temporelle des variables de trait phénotypique. Cette analyse nous permet de réduire le système d’équations des profils d’ondes progressives à dimension infinie à un système d’EDO à

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25

Vuylsteke, Xavier. "Development of a reference method based on the fast multipole boundary element method for sound propagation problems in urban environments : formalism, improvements & applications." Thesis, Paris Est, 2014. http://www.theses.fr/2014PEST1174/document.

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Décrit comme l'un des algorithmes les plus prometteurs du 20ème siècle, le formalisme multipolaire appliqué à la méthode des éléments de frontière, permet de nos jours de traiter de larges problèmes encore inconcevables il y a quelques années. La motivation de ce travail de thèse est d'évaluer la capacité, ainsi que les avantages concernant les ressources numériques, de ce formalisme pour apporter une solution de référence aux problèmes de propagation sonore tri-dimensionnels en environnement urbain, dans l'objectif d'améliorer les algorithmes plus rapides déjà existants. Nous présentons la th

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26

Maddi, Anis. "Nonreciprocal control of sound waves using thermoacoustic and active electroacoustic elements." Electronic Thesis or Diss., Le Mans, 2025. http://www.theses.fr/2025LEMA1003.

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Ce travail est consacré à la conception de systèmes acoustique non-réciproques, en faisant usage soit de l'effet thermoacoustique, soit d’éléments actifs munis d’une boucle de rétroaction électroacoustique asymétrique. Ces deux méthodes permettent de briser la réciprocité des ondes sonores aériennes en basse fréquence et sur une large bande, tout en préservant la linéarité du système considéré. Les deux méthodes étant basées sur un apport d’énergie externe (travail ou chaleur), elles ont également la propriété intéressante d’introduire du gain ou de la perte dans le système.L'effet thermoacous

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27

Luppé, Francine. "Contribution a l'etude de l'onde de scholte-stoneley a differentes interfaces fluide parfait/solide elastique." Paris 7, 1987. http://www.theses.fr/1987PA077222.

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28

Prášek, Martin. "Optimalizace výfukového potrubí zážehového motoru." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-229372.

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The master thesis is focused on optimizing existing or proposal for a new exhaust tracts on the Volkswagen Polo moving series rally-cross A1 division. The car is powered by concern, water-cooled, atmospheric engine capacity 1599 ccm. To achieve the objectives of the lessons are applied as a theoretical nature (analytical calculation), especially the advanced approaches of the software environment from the firm Lotus. Exhaust treatment systems are designed to suit all rules FIA Sports Association.

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29

Yang, Mingming. "Development of the partition of unity finite element method for the numerical simulation of interior sound field." Thesis, Compiègne, 2016. http://www.theses.fr/2016COMP2282/document.

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Dans ce travail, nous avons introduit le concept sous-jacent de PUFEM et la formulation de base lié à l'équation de Helmholtz dans un domaine borné. Le processus d'enrichissement de l'onde plane de variables PUFEM a été montré et expliqué en détail. L'idée principale est d'inclure une connaissance a priori sur le comportement local de la solution dans l'espace des éléments finis en utilisant un ensemble de fonctions d'onde qui sont des solutions aux équations aux dérivées partielles. Dans cette étude, l'utilisation des ondes planes se propageant dans différentes directions a été favorisée car

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30

Tafur, Jimenez Luis. "Assessment of a hybrid numerical approach to estimate sound wave propagation in an enclosure and application of auralizations to evaluate acoustical conditions of a classroom to establish the impact of acoustic variables on cognitive processes." Thesis, University of Southampton, 2016. https://eprints.soton.ac.uk/398545/.

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In this research, the concept of auralization is explored taking into account a hybrid numerical approach to establish good options for calculating sound wave propagation and the application of virtual sound environments to evaluate acoustical conditions of a classroom, in order to determine the impact of acoustic variables on cognitive processes. The hybrid approach considers the combination of well-established Geometrical Acoustic (GA) techniques and the Finite Element Method (FEM), contemplating for the latter the definition of a real valued impedance boundary condition related to absorptio

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31

Doli, Valentin. "Phénomènes de propagation de champignons parasites de plantes par couplage de diffusion spatiale et de reproduction sexuée." Thesis, Rennes 1, 2017. http://www.theses.fr/2017REN1S139/document.

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On considère des organismes qui mixent reproduction sexuée et asexuée, dans une situation où la reproduction sexuée fait intervenir à la fois de la dispersion spatiale et de la limitation d'appariement. Nous proposons un modèle qui implique deux équations couplées, la première étant une équation différentielle ordinaire de type logistique, la seconde étant une équation de réaction-diffusion. Grâce à des valeurs réalistes des différents coefficients, il s'avère que la deuxième équation fait intervenir une échelle de temps rapide, alors que la première fait intervenir une échelle de temps lente.

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32

Andreeva, Tatiana A. "Ultrasonic technique in determination of grid-generated turbulent flow characteristics." Link to electronic thesis, 2003. http://www.wpi.edu/Pubs/ETD/Available/etd-1010103-153049.

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33

Grialou, Matthieu. "Vibro-acoustics substructuring : Combining simulations and experimental identification of subdomains for low frequency vehicle acoustics." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEI109/document.

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La sonorité de l’échappement joue un rôle significatif sur le confort acoustique des occupants, ainsi que sur le caractère du véhicule. L’étude proposée porte sur la problématique industrielle suivante : « Description et quantification de la transmission du son entre la bouche d’échappement et l’intérieur du véhicule ». Physiquement la transmission sonore entre l’échappement et l’intérieur du véhicule s’effectue en trois étapes : Propagation des ondes sonores de la canule à la surface extérieure du véhicule et conversion en énergie vibratoire (1) ; Le bruit structurel se propage de la peau ext

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34

Gry, Laurent. "Modélisation du comportement dynamique d'une voie TGV pour la réduction du bruit de roulement." Châtenay-Malabry, Ecole centrale de Paris, 1995. http://www.theses.fr/1995ECAP0419.

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Un modèle de voie périodique a été développé afin de réduire le bruit émis dans l'environnement durant le passage d'un train. Ce modèle, prenant en compte les déformations de la section du rail, couvre une large gamme de fréquences, 0 - 5000 Hz. La considération d'un appui discret le rend cependant moins performant dans les hautes fréquences, pour lesquelles les ondes propagatives émises sur une travée ont une longueur d'onde proche de la longueur d'appui. Une méthode générale d'analyse des milieux périodiques unidimensionnels est alors proposée afin de prendre en compte l'effet de la longueur

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35

Xiong, Lei. "Use of mode coupling to enhance sound attenuation in acoustic ducts : effects of exceptional point." Thesis, Le Mans, 2016. http://www.theses.fr/2016LEMA1017/document.

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Deux stratégies sont présentées à utiliser des effets de couplage de modes pour l’amplification de l’atténuation du son dans les conduits acoustiques. La première est de coupler le mode incident propagatif avec un mode localisé, aussi appelé résonance de Fano. Cette stratégie est présentée et validée dans un système conduit-cavité et un guide d’onde partiellement traité en paroi avec un matériau à réaction locale. La méthode “R-matrix” est introduite pour résoudre le problème de propagation d’onde. Une annulation de la transmission se produit quand un mode piégé (qui es

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Sambuc, Clément. "Refined damped equivalent fluid models for acoustics." Doctoral thesis, Universite Libre de Bruxelles, 2015. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209144.

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The acoustics of small cavities raises interest of the scientific community since it involves particular damping mechanisms. In fluid dynamics, when a small perturbation is propagating within a Newtonian and heat-conducting fluid bounded by a rigid and isothermal surface, viscous and thermal dissipative mechanisms are generated near the walls. Such effects can have significant impact on the acoustic behaviour of the system.<p>Several types of practical applications can be cited, among which: hearing aids, micro-electro-mechanical systems (transducers, microphones and loud-speakers), absorbing

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Patris, Julie. "Contributions en méthodes pour le suivi de mysticètes par acoustique passive." Electronic Thesis or Diss., Toulon, 2019. http://www.theses.fr/2019TOUL0016.

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La surveillance par acoustique passive est un outil d'importance croissante pour l'étude des mammifères marins. Cette thèse pose des nouveaux modèles pour l'étude du plus grand d'entre eux, la baleine bleue (Balaenoptera musculus), qui émet de très basses fréquences. Pour ce faire, nous avons enregistré un corpus inédit dans l'archipel de Humboldt au nord du Chili. Nos données révèlent un chant caractéristique de la baleine bleue 'chilienne', dont nous étudions la structure pulsée et l'évolution au cours des dernières décennies. Le classement en signal tonal ou non-tonal nous permet, en nous f

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Völz, Uwe. "Berechnung der Schallausbreitung in transversalisotropen Werkstoffen zur Festlegung optimaler Parameter für die Ultraschallprüfung mit Gruppenstrahlern durch Einführung einer vierdimensionalen Punktrichtwirkung." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-157759.

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Die zerstörungsfreie Ultraschallprüfung von akustisch anisotropen Werkstoffen stellt auch heute noch eine Herausforderung dar. Die Gefügestruktur in solchen Materialien beeinflusst die Wellenausbreitung derart, dass es zum einen zu starken Streuungen durch die großflächigen Korngrenzen und zum anderen, aufgrund der akustischen Anisotropie, zu einer Richtungsabhängigkeit der Schallgeschwindigkeiten kommt. In den vergangenen Jahren wurden bereits Lösungsansätze zur mathematischen Modellierung der Schallausbreitung in anisotropen Materialien vorgestellt. Diese basieren in der Regel auf FEM- bzw.

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39

Puech, Laurent. "3He polarisé : propriétés magnétoélastiques et comparaison avec deux systèmes à fermions lourds : obtention d'hélium polarisé à 50 mK et étude des relaxations d'énergie dans ce système." Grenoble 1, 1988. http://www.theses.fr/1988GRE10036.

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Interpretation de l'abaissement de la pression de fusion lorsque la fusion est plus rapide que le temps de relaxation de la polarisation de **(3)he d'apres l'etude theorique de la morphologie de l'interface liquide-solide lors de la fusion de **(3)he solide polarise. Tendance au metamagnetisme de **(3)he liquide pour une polarisation de equiv. A 20 %, a 0,1 k, et absence d'anomalie dans la vitesse du son mesuree a ce taux de polarisation. Possibilite de refroidir le liquide polarise au-dessus de 0,1 k en un temps tres court compare a celui de la relaxation de polarisation. Etude experimentale

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40

Векерик, В. В. "Акустичний контроль геометричних параметрів обсадних колон в свердловині". Thesis, Івано-Франківський національний технічний університет нафти і газу, 2004. http://elar.nung.edu.ua/handle/123456789/4014.

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Показано і обгрунтовано, що найбільш інформативним з параметрів, які відповідають за працездатність обсадних колон і визначають їх фактичний технічний стан, є геометричні параметри. На основі проведених теоретичних та експериментальних досліджень розроблено способи акустичного контролю геометричних параметрів трубних виробів зсередини та методологію застосування з цією метою акустичного луна-імпульсного методу контролю в експлуатаційних умовах свердловини. Експериментально досліджено залежність швидкості поширення поздовжньої ультразвукової хвилі в матеріалі обсадних труб та чутливості акустич

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Григорський, С. Я. "Удосконалення технології експлуатації нафтопроводів з урахуванням нештатних ситуацій". Thesis, Івано-Франківський національний технічний університет нафти і газу, 2015. http://elar.nung.edu.ua/handle/123456789/4726.

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За результатами теоретичних та експериментальних досліджень вирішена наукова задача підвищення ефективності та надійності експлуатації магістральних нафтопроводів шляхом мінімізації негативного впливу нештатних ситуацій. Проведено експериментальні дослідження гідродинаміки перехідних процесів, спричинених зупинками насосних агрегатів на нафтоперекачувальних станціях (НПС) нафтопроводу. Встановлені закономірності зміни обертової частоти вала насосних агрегатів типу НМ у часі в процесі їх зупинки. Визначена фактична швидкість розповсюдження хвилі тиску нафтопроводом під час перехідного процесу.

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Wang, Che-Chang, and 汪哲彰. "Simulation of Indoor Sound Wave Propagation using SBR-image Method." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/20762252586372373806.

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碩士<br>國立臺灣大學<br>電機工程學系<br>85<br>In this thesis, we will propose a method, the SBR-image method, tosimulate the sound wave propagation in a large empty room. With this method, weshoot ray tubes from a sound source until it hits a wall which we assume to bea rigid wall for simplicity. According to the law of reflection, we can tracethe ray tube in its new direction towards the next wall. In every bounce, wehave to examine whether the receiver is in the ray tube. If the ray tube hitthe receive

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Lin, Benjamin S. M., and 林士民. "The sound wave propagation properties of two dimensional wedge-shape ocean." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/76718830332356275381.

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碩士<br>國立臺灣大學<br>造船及海洋工程學研究所<br>87<br>The finite element method will be used to compute the sound pressure distribution of a wedge-shape sea due to a line source. The relationships of the size of the shadow-zone among those parameters location and frequency of the source, the apex angle, depth of source will be analyzed.

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Chiang, I.-Ting, and 江怡霆. "Simulation of Indoor Sound Wave Propagation using 2.5D SBR-Image Method." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/21489825061481380074.

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碩士<br>國立臺灣大學<br>電機工程學系<br>86<br>In this thesis,we will propose a method,the 2.5D SBR-image method, to simulate sound wave propagation in a large empty room.First,we simplify a 3D problem into a 2D one by initially neglecting the third dimension.Then,we shoot 2D ray tubes from a sound source until it hits a wall which we assume to be a rigid wall in most cases for simplicity.In accordance with the law of reflection,we can trace the ray tube in its new direction towards the next wall.In every bounce,

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Chang, Wei-Ju, and 張維儒. "Acoustic Pulse Propagation in a Fluctuating Ocean with Range- Dependent Sound-Speed Profile." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/01854295189485298956.

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碩士<br>國立交通大學<br>電信工程研究所<br>84<br>When an acoustic pulse in a random fluctuating ocean with a deterministic sound-speed profile, it is distorted since the every frequency component experience different extents of scattering from the random inhomogeneity and echo numbers. Here, the split-step method is used to simulate an acoustic pulse with a 3kHz carrier propagating through a turbulent ocean with range- independent / -dependent sound-speed profiles. It is found that (1) For a single frequen

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He, Jia-Hao, and 何家豪. "Tunable unidirectional sound wave propagation though multi-configuration sonic-crystal-based acoustic diode." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/7d2vp3.

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碩士<br>國立臺灣大學<br>工程科學及海洋工程學研究所<br>106<br>In this research, the sonic-crystal-based tunable acoustic diode is proposed. This proposed acoustic diode can tune working frequency ranges by transforming its configurations. The acoustic characteristics of nonlinear transmission in proposed structure have favorable agreement between numerical results and experimental results. For these results, all the numerical results are calculated by using COMSOL Multiphysics 5.0 and the experiment results are measured in anechoic chamber. Moreover, effects of rotating angles and allowable errors of rotating angle

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Shih, Chi Liu, and 劉詩麒. "Approach to Structure-Borne Sound Propagation in Grillage by Stress Wave Finite Element Method." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/06046791031959508250.

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碩士<br>國立海洋大學<br>系統工程暨造船學系<br>90<br>To solve the finite element method in the high frequency vibration of general structure that faces sizes of element of grid problems, our research has developed another new element that derives stress wave individually from a confined beam of vibration mode and compiles a matrix type. Without any limitation on sizes of grid, the advantage of new element can remain theoretical mode basically and does not restrict the range of frequency. Furthermore, under the structure of finite element method, it has developed a grillage mode of program to calculate any beam

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Horoshenkov, Kirill V., David C. Hughes, and A. Cwizen. "The sound speed and attenuation in loose and consolidated granular formulations of high alumina cements." 2003. http://hdl.handle.net/10454/3691.

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No<br>Clinkers of high alumina cements are separated into three granular formulations with particle sizes in the range 0.6-0.71 mm, 0.71-1.18 mm and greater than 1.18 mm. These are used to manufacture consolidated samples of porous concrete in an autoclave. The acoustic and microscopic properties of loose and consolidated porous samples of concrete are investigated using both experimental methods and mathematical modelling. Values of porosity, flow resistivity, tortuosity and parameters of the pore size distribution are determined and used to predict closely the sound speed, acoustic attenuati

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D'Souza, Derrell. "Stratified-medium sound speed profiling for CPWC ultrasound imaging." Thesis, 2020. http://hdl.handle.net/1828/11925.

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Coherent plane-wave compounding (CPWC) ultrasound is an important modality enabling ultrafast biomedical imaging. To perform CWPC image reconstruction for a stratified (horizontally layered) medium, one needs to know how the speed of sound (SOS) varies with the propagation depth. Incorrect sound speed and layer thickness assumptions can cause focusing errors, degraded spatial resolution and significant geometrical distortions resulting in poor image reconstruction. We aim to determine the speed of sound and thickness values for each horizontal layer to accurately locate the recorded reflection

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Wang, Pao-an, and 王保安. "Waveguide Propagation in an Ocean With a Sediment Layer of Continuous Sound-Speed and Density Variations." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/11902419243314364538.

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碩士<br>國立中山大學<br>海下技術研究所<br>86<br>Generally speaking, when treating wave propagation in an ocean waveguide, the density is assumed to be constant in the media. However, the study report of Hamilton[1] shows that there exists a transition layer in the water-sediment interface, in which the density varies continuously and gradually with depth. The objective of this thesis project is to study the effects of such transition layer on the reflection coefficient and wave propagation in an waveguide environment.The first part of this thesis is to derive the wave equation from the governing equation for

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