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Dissertations / Theses on the topic 'Spectral mechanics'

Author: Grafiati

Published: 2 June 2025

Last updated: 31 July 2025

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1

Portmann, Fabian. "Spectral Inequalities and Their Applications in Quantum Mechanics." Doctoral thesis, KTH, Matematik (Avd.), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-145210.

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The work presented in this thesis revolves around spectral inequalities and their applications in quantum mechanics. In Paper A, the ground state energy of an atom confined to two dimensions is analyzed in the limit when the charge of the nucleus Z becomes very large. The main result is a two-term asymptotic expansion of the ground state energy in terms of Z. Paper B deals with Hardy inequalities for the kinetic energy of a particle in the presence of an external magnetic field. If the magnetic field has a non-trivial radial component, we show that Hardy’s classical lower bound can be improved

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2

Savvides, Abraham. "Application of two-dimensional spectral/finite-difference and spectral/hp finite-element methods to cylinder flows." Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.264204.

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3

Hu, Zhihua. "Spectral fatigue analysis techniques." Thesis, University College London (University of London), 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362446.

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4

Crossley, Peter Simon. "On spectral methods for shock wave calculations." Thesis, Manchester Metropolitan University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361577.

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5

Mickelin, Oscar. "On Spectral Inequalities in Quantum Mechanics and Conformal Field Theory." Thesis, KTH, Matematik (Avd.), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-167969.

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Following Exner et al. (Commun. Math. Phys. 26 (2014), no. 2, 531–541), we prove new Lieb-Thirring inequalities for a general class of self-adjoint, second order differential operators with matrix-valued potentials, acting in one space-dimension. This class contains, but is not restricted to, the magnetic and non-magnetic Schrödinger operators. We consider the three cases of functions defined on all reals, all positive reals, and an interval, respectively, and acquire three different kinds of bounds. We also investigate the spectral properties of a family of operators from conformal field theo

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6

Roberts, Stephen. "Spectral decompositions for evolution operators of mixing dynamical systems." Thesis, University of Warwick, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247439.

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7

Eppanapelli, Lavan Kumar. "Classification of different types of snow using spectral and angular imaging." Licentiate thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-59817.

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The current thesis work details a non-contact detection approach concerningclassification of snow with different physical properties such as grain size, densityand specific surface area (SSA). In this approach, reflected light from snowsurfaces is measured as a function of wavelength and viewing geometry. Essentiallya detector (either a near-infrared (NIR) camera or a spectrometer) and anillumination source are needed to measure the spectrally and angularly resolvedbidirectional reflectance from snow. Classification of snow types is performedbased on the absorption and scattering properties of

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8

Boström, Erik. "Boundary Conditions for Spectral Simulations of Atmospheric Boundary Layers." Licentiate thesis, KTH, Stabilitet, Transition, Kontroll, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-218054.

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An atmospheric boundary layer (ABL) is generally a very high Reynolds number boundary layer over a fully rough surface that is influenced by different external forces. Numerical simulations of ABLs are typically demanding, particularly due to the high Reynolds numbers. Large eddy simulation (LES) where the grid filtered Navier--Stokes equations are solved together with a turbulence model for the subgrid-scale motions is the most accurate and widely used technique to date for ABLs. However, high Reynolds numbers, filtered equations and rough surfaces do not support the simple no-slip boundary c

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9

Black, Gregory Martin. "Photoionization cross-sections for the modelling of X-ray spectral data in astrophysics." Thesis, Queen's University Belfast, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263365.

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10

Malek, Alaeddin. "Numerical spectral solution of elliptic partial differential equations using domain decomposition techniques." Thesis, Cardiff University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241798.

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11

Kleusberg, Elektra. "Wind turbine simulations using spectral elements." Licentiate thesis, KTH, Stabilitet, Transition, Kontroll, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-207630.

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Understanding the flow around wind turbines is a highly relevant research question due to the increased interest in harvesting energy from renewable sources. This thesis approaches the topic by means of numerical simulations using the actuator line method and the incompressible Navier–Stokes equations in the spectral element code Nek5000. The aim is to gain enhanced understanding of the wind turbine wake structure and wind turbine wake interaction. A verification study of the method and implementation is performed against the finite volume solver EllipSys3D using two types of turbines, an idea

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12

Lee, Jong-eao John. "The inverse spectral solution, modulation theory and linearized stability analysis of N-phase, quasi-periodic solutions of the nonlinear Schrodinger equation /." The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu148726601122429.

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13

Sivan, D. D. "Design and structural modifications of vibratory systems to achieve prescribed modal spectra /." Title page, contents and abstract only, 1997. http://web4.library.adelaide.edu.au/theses/09PH/09phs6238.pdf.

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14

Pontaza, Juan Pablo. "Least-squares variational principles and the finite element method: theory, formulations, and models for solid and fluid mechanics." Diss., Texas A&M University, 2003. http://hdl.handle.net/1969.1/288.

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We consider the application of least-squares variational principles and the finite element method to the numerical solution of boundary value problems arising in the fields of solidand fluidmechanics.For manyof these problems least-squares principles offer many theoretical and computational advantages in the implementation of the corresponding finite element model that are not present in the traditional weak form Galerkin finite element model.Most notably, the use of least-squares principles leads to a variational unconstrained minimization problem where stability conditions such as inf-sup co

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15

Engin, Erjona. "Dynamic Analysis Of Flow In Two Dimensional Flow." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609374/index.pdf.

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The Poiseuille Flow is the flow of a viscous incompressible fluid in a channel between two infinite parallel plates. The behaviour of flow is properly described by the well-known Navier-Stokes Equations. The fact that Navier-Stokes equations are partial differential equations makes their solution difficult. They can rarely be solved in closed form. On the other hand, numerical techniques can be applied successfully to the well-posed partial differential equations. In the present study pseudo-spectral method is implemented to analyze the Poiseuille Flow. The pseudo-spectral method is a high-ac

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16

Hedberg, Lundblad Louise, and Anna Lund. "Comparison of Fatigue Life Evaluation Methods." Thesis, KTH, Hållfasthetslära, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-298345.

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The aim of this thesis is to investigate a selected set of fatigue life calculation methods and evaluate if they are suitable for fatigue life estimation of truck components at Scania. Failure due to fatigue can be cause by road induced vibrations, which is an inevitable phenomenon trucks are exposed to. By estimating when and where these components will fail, they can be designed to reduce the amount of failure per vehicle. Three types of fatigue life calculation methods, namely equivalent stress methods, critical plane methods and spectral methods, have been evaluated. These are methods for

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17

Offermans, Nicolas. "Towards adaptive mesh refinement in Nek5000." Licentiate thesis, KTH, Mekanik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-217501.

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The development of adaptive mesh refinement capabilities in the field of computational fluid dynamics is an essential tool for enabling the simulation of larger and more complex physical problems. While such techniques have been known for a long time, most simulations do not make use of them because of the lack of a robust implementation. In this work, we present recent progresses that have been made to develop adaptive mesh refinement features in Nek5000, a code based on the spectral element method. These developments are driven by the algorithmic challenges posed by future exascale supercomp

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18

Dahl, Jason F. "Time Aliasing Methods of Spectrum Estimation." Diss., CLICK HERE for online access, 2003. http://contentdm.lib.byu.edu/ETD/image/etd157.pdf.

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19

Rahimian, Abtin. "Parallel algorithms for direct blood flow simulations." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/43611.

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Fluid mechanics of blood can be well approximated by a mixture model of a Newtonian fluid and deformable particles representing the red blood cells. Experimental and theoretical evidence suggests that the deformation and rheology of red blood cells is similar to that of phospholipid vesicles. Vesicles and red blood cells are both area preserving closed membranes that resist bending. Beyond red blood cells, vesicles can be used to investigate the behavior of cell membranes, intracellular organelles, and viral particles. Given the importance of vesicle flows, in this thesis we focus in efficient

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20

Novell, Sara T. "Design of Structural Stand for High-Precision Optics Microscopy." DigitalCommons@CalPoly, 2020. https://digitalcommons.calpoly.edu/theses/2132.

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Lawrence Livermore National Lab (LLNL) is home to the National Ignition Facility (NIF), the world’s largest and most energetic laser. Each of the 192 beamlines contains dozens of large optics, which require offline damage inspection using large, raster-scanning microscopes. The primary microscope used to measure and characterize the optical damage sites has a precision level of 1 µm. Mounted in a class 100 clean room with a raised tile floor, the microscope is supported by a steel stand that structurally connects the microscope to the concrete ground. Due to ambient vibrations experienced in t

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21

Freire, Márcio de Melo. "Funções de Green em Mecânica Estatística." reponame:Repositório Institucional da UFC, 2014. http://www.repositorio.ufc.br/handle/riufc/9059.

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FREIRE, Márcio de Melo. Funções de Green em Mecânica Estatística. 2014. 56 f. Dissertação (Mestrado em Física) - Programa de Pós-Graduação em Física, Departamento de Física, Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2014.<br>Submitted by Edvander Pires (edvanderpires@gmail.com) on 2014-09-12T19:48:53Z No. of bitstreams: 1 2014_dis_mmfreire.pdf: 935092 bytes, checksum: 28a3a9a1ed16462d01e40ff411a01564 (MD5)<br>Approved for entry into archive by Edvander Pires(edvanderpires@gmail.com) on 2014-09-12T19:50:01Z (GMT) No. of bitstreams: 1 2014_dis_mmfreire.pdf: 935092 bytes, chec

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22

Figueroa, Leonardo E. "Deterministic simulation of multi-beaded models of dilute polymer solutions." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:4c3414ba-415a-4109-8e98-6c4fa24f9cdc.

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We study the convergence of a nonlinear approximation method introduced in the engineering literature for the numerical solution of a high-dimensional Fokker--Planck equation featuring in Navier--Stokes--Fokker--Planck systems that arise in kinetic models of dilute polymers. To do so, we build on the analysis carried out recently by Le~Bris, Leli\`evre and Maday (Const. Approx. 30: 621--651, 2009) in the case of Poisson's equation on a rectangular domain in $\mathbb{R}^2$, subject to a homogeneous Dirichlet boundary condition, where they exploited the connection of the approximation method wit

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23

Karkar, Sami. "Méthodes numériques pour les systèmes dynamiques non linéaires : application aux instruments de musique auto-oscillants." Phd thesis, Aix-Marseille Université, 2012. http://tel.archives-ouvertes.fr/tel-00742651.

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Ces travaux s'articulent autour du calcul des solutions périodiques dans les systèmes dynamiques non linéaires, au moyen de méthodes numériques de continuation. La recherche de solutions périodiques se traduit par un problème avec conditions aux limites périodiques, pour lequel nous avons implémenté deux méthodes d'approximation : - Une méthode spectrale dans le domaine fréquentiel : l'équilibrage harmonique d'ordre élevé, qui repose sur une formulation quadratique des équations. Nous proposons en outre une formulation originale permettant d'étendre cette méthode aux cas de non-linéarités non

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24

Dumon, Antoine. "Réduction dimensionnelle de type PGD pour la résolution des écoulements incompressibles." Phd thesis, Université de La Rochelle, 2011. http://tel.archives-ouvertes.fr/tel-00644565.

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L'objectif de ce travail consiste à développer la méthode de résolution PGD (Proper Generalized Decomposition), qui est une méthode de réduction de modèle où la solution est recherchée sous forme séparée, à la résolution des équations de Navier-Stokes. Dans un premier temps, cette méthode est appliquée à la résolution d'équations modèles disposant d'une solution analytique. L' équation de diffusion stationnaire 2D et 3D, l'équation de diffusion instationnaire 2D et les équations de Burgers et Stokes sont traitées. Nous montrons que dans tous ces cas la méthode PGD permet de retrouver les solut

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25

Le, Floch Yohann. "Théorie spectrale inverse pour les opérateurs de Toeplitz 1D." Phd thesis, Université Rennes 1, 2014. http://tel.archives-ouvertes.fr/tel-01065441.

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Dans cette thèse, nous prouvons des résultats de théorie spectrale, directe et inverse, dans la limite semi-classique, pour les opérateurs de Toeplitz autoadjoints sur les surfaces. Pour les opérateurs pseudo-différentiels, les résultats en question sont déjà connus, et il est naturel de vouloir les étendre aux opérateurs de Toeplitz. Les conditions de Bohr-Sommerfeld usuelles, qui caractérisent les valeurs propres proches d'une valeur régulière du symbole principal, ont été obtenues il y a quelques années seulement pour les opérateurs de Toeplitz. Notre contribution consiste en l'extension de

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26

Freire, MÃrcio de Melo. "FunÃÃes de Green em mecÃnica estatÃstica." Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=12311.

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Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico<br>Neste trabalho estabeleceremos as definiÃÃes das funÃÃes de Green em mecÃnica estatÃstica e suas propriedades bÃsicas. Estas funÃÃes dependem duplamente do tempo e da temperatura. Isto pode ser observado por meio de suas definiÃÃes, onde aparecem os valores mÃdios dos produtos de operadores. Neste caso a mÃdia Ã feita sobre o ensemble grÃo-canÃnico. Os operadores envolvidos nestas funÃÃes satisfazem a equaÃÃo de movimento de Heisenberg, o que nos permite descrever as equaÃÃes de evoluÃÃo para as funÃÃes de Green. Por meio da rep

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27

Piquet, Arthur. "Analyse physique et simulation numérique des phénomènes de décollement de jet dans les tuyères supersoniques." Thesis, Normandie, 2017. http://www.theses.fr/2017NORMIR09/document.

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Cette thèse, initiée par un programme de coopération franco-britannique entre la DGA et la DSTL, est consacrée à l’étude des phénomènes de décollement de jet au sein des tuyères propulsives sur-détendu. L’aérothermodynamique des systèmes propulsifs (missile, avion supersonique ou lanceur) est un des domaines de la mécanique des fluides où des progrès décisifs restent à réaliser pour améliorer les performances des ensembles moteurs, en terme de bilan de poussée, de stabilité, de fiabilité et de réduction de nuisances (bruit, émission de polluants, etc.). Les conditions de vols et la complexité

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28

Frantz, Nicolas. "Théorie spectrale et théorie de la diffusion pour des opérateurs non-auto-adjoints." Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0125.

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Dans cette thèse, nous considérons un opérateur non-auto-adjoint sur un espace de Hilbert de la forme «H=H_0+CWC», où «H_0» est auto-adjoint, «W» est un opérateur borné et «C» est un opérateur relativement compact par rapport à «H_0». De plus on suppose que «C» est un opérateur positif et injectif tel que «CRes_0(z)C» est uniformément borné pour «zinCbackslashR». Nous définissons les singularités spectrales de «H» comme l'ensemble des «lambdainsigma_mathrm{ess}(H_0)» du spectre de «H» tel que «CRes_H(lambdapm i0^+)CW» n'a pas de limite quand «varepsilonrightarrow 0^+». D'abord nous étudions la

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29

Djaka, Komlan Sénam. "Développement et applications d’une technique de modélisation micromécanique de type "FFT" couplée à la mécanique des champs de dislocations." Thesis, Université de Lorraine, 2016. http://www.theses.fr/2016LORR0250/document.

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Dans ce mémoire, des méthodes spectrales basées sur la transformée de Fourier rapide ("fast Fourier transform" en anglais notée "FFT") sont développées pour résoudre les équations de champs et d’évolution des densités de dislocations polarisées ou géométriquement nécessaires dans la théorie de la mécanique des champs de dislocations ("Field Dislocations Mechanics" en anglais et notée "FDM") et de son extension phénoménologique et mésoscopique ("Phenomenological Mesoscopic Field Dislocations Mechanics" en anglais et notée "PMFDM"). Dans un premier temps, une approche spectrale a été développée

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30

Le, Touzé David. "Méthodes spectrales pour la modélisation non-linéaire d'écoulements à surface libre instationnaires." Phd thesis, Ecole centrale de nantes - ECN, 2003. http://tel.archives-ouvertes.fr/tel-00370200.

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Les méthodes spectrales sont connues pour leurs propriétés de convergence rapide et de précision. Cependant, leur application à l'hydrodynamique navale reste encore aujourd'hui peu étendue. Le but de ce doctorat est d'étudier les possibilités de leur application à la génération et propagation de houle, dans le cadre de la théorie des écoulements potentiels. <br />Un bilan des différentes approches spectrales employées jusqu'à présent en hydrodynamique navale est d'abord dressé, étayant le choix des techniques développées au cours de ce travail. L'étude des propriétés de ces techniques est ensu

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31

Oudich, Hamza. "Analytical Investigation of Planetary Gears Instabilities and the Impact of Micro-Macro Geometry Modifications." Thesis, KTH, Farkostteknik och Solidmekanik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-276775.

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Due to their large torque-speed ratio and transmission efficiency, planetary gears are widely used in the automotive industry. However, high amplitude vibrations remain their critical weakness, which limits their usage especially when new strict noise legislations come into action. A new approach to handle the instability problems of planetary gears encountered in real industrial context is presented in this work. First, the dynamic response of a planetary gear failing to pass the noise regulations is theoretically investigated through an analytical model. The equations of motion were solved u

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32

Huang, Yi Ph D. Massachusetts Institute of Technology. "Spectral engineering for solar-thermal and thermal-radiative systems." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/127052.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020<br>Cataloged from the official PDF of thesis.<br>Includes bibliographical references (pages 224-239).<br>Increasing energy efficiency for power generation and reduction of energy consumption are two important venues to address the energy supply and global warming challenges we face today. Radiation from the sun and terrestrial heat sources can be harvested for power generation. It is also an important heat transfer channel, with which one can control in order to regulate the temperature of ob

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33

Marozeau, Jeremy. "L'effet de la fréquence fondamentale sur le timbre." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2004. http://tel.archives-ouvertes.fr/tel-00008742.

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Cette thèse est dédiée à l'étude de l'effet de la fréquence fondamentale (Fo) sur le timbre. Elle relate sept expériences utilisant des stimuli issus d'instruments naturels ou synthétiques. <br> Les expériences effectuées consistaient à demander à des sujets de juger des dissemblances de timbre entre des paires de stimuli sans tenir compte de leur éventuelle différence de hauteur. Les expériences I-II et III utilisaient des stimuli issus d'instruments de musique de l'orchestre occidental. Les autres expériences utilisaient des stimuli synthétisés par addition de sons purs. L'expérience I prése

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34

Lu, Yu-Yu. "Experimental Study of Installation Effects on Cooling Fan Noise." Thesis, KTH, Marcus Wallenberg Laboratoriet MWL, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-302269.

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Owing to the ever-changing developments of battery and electric powertrain, vehicle electrification is the trend in the future. Without the presence of a combustion engine, masking effect from it reduces and noises from other components become perceivable. Among all, the cooling fan is one of the major noise sources. The design of cooling fan modules is usually carried out in the early stage before building prototype vehicles. Therefore, it is essential to come up with a method for selecting optimal fan design without performing complete vehicle testing. This is a Master's degree project in co

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Kranz, Michael S. "Micro-mechanical sensor for the spectral decomposition of acoustic signals." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/39496.

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An array of electret-biased frequency-selective resonant microelectromechanical system (MEMS) acoustic sensors was proposed to perform analysis of stress pulses created during an impact between two materials. This analysis allowed classification of the stiffness of the materials involved in the impact without applying post-impact signal processing. Arrays of resonant MEMS sensors provided filtering of the incident stress pulse and subsequent binning of time-domain waveforms into frequency-based spectra. Results indicated that different impact conditions and materials yielded different spectral

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Ullah, Abid. "Mechanisms for Enhancing Spectrum Utilization in a Spectrum Access System." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/84932.

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The goal of this thesis is to build a Protected Shared Access Model (PSAM) through database enabled Spectrum Access System (SAS). A model for the SAS is proposed, which is based on our vision for the SAS as a more dynamic and responsive architecture as a geolocation database than the current TVWS database. Major functions and capabilities of the model include, calculations of exclusion zone (EZ) of primary users with different operational parameters, use interference estimation techniques for predicting interference levels that will be generated by the new secondary users (SUs) and existing sy

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Vanon, Riccardo. "Zonal flows in accretion discs and their role in gravito-turbulence." Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/267991.

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This thesis focuses on the evolution of zonal flows in self-gravitating accretion discs and their resulting effect on disc stability; it also studies the process of disc gravito-turbulence, with particular emphasis given to the way the turbulent state is able to extract energy from the background flow and sustain itself by means of a feedback. Chapters 1 and 2 provide an overview of systems involving accretion discs and a theoretical introduction to the theory of accretion discs, along with potential methods of angular momentum transport to explain the observed accretion rates. To address the

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38

Weinstein, Lee A. (Lee Adragon). "Improving solar thermal receiver performance via spectral and directional selectivity." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/113762.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 142-158).<br>Adoption of renewable energy technologies has accelerated rapidly in recent years due to growing energy demand and concerns over climate change. Among renewable energy sources, solar energy conversion systems are particularly promising due to the abundance of solar energy reaching Earth. Despite its abundance, the solar resource is dilute, so solar energy must be collected efficiently in order for

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Joo, Chulmin 1976. "Spectral-domain optical coherence phase microscopy for quantitative biological studies." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/43142.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.<br>Includes bibliographical references.<br>Conventional phase-contrast and differential interference contrast microscopy produce high contrast images of transparent specimens such as cells. However, they do not provide quantitative information or do not have enough sensitivity to detect nanometerlevel structural alterations. We have developed spectral-domain optical coherence phase microscopy (SD-OCPM) for highly sensitive quantitative phase imaging in 3D. This technique employs common-path spectral-

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40

Brenner, Ceri M. "Laser-driven proton beams : mechanisms for spectral control and efficiency enhancement." Thesis, University of Strathclyde, 2012. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=18234.

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This thesis reports on investigations of proton acceleration driven by the interaction of short, intense laser pulses with thin, solid targets. Laser-driven plasma interactions are used to establish accelerating quasi-electrostatic field gradients, on the rear surface of the target, that are orders of magnitude higher than the current limit of conventional, radio-frequency-based accelerator technology. The resulting high energy (multi-MeV) proton beams are highly laminar, have ultra-low emittance, and the inherently broad energy spectrum is particularly effective for use in proton imaging, hea

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41

Sahm, David Karl. "The classical mechanics of mode-mode energy transfer in polyatomic molecules." Diss., Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/29997.

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Philipossian, Ara, Yasa Sampurno, and Lauren Peckler. "Chemical Mechanical Planarization and Old Italian Violins." MDPI AG, 2018. http://hdl.handle.net/10150/627056.

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Previous studies have shown that spectral analysis based on force data can elucidate fundamental physical phenomena during chemical mechanical planarization (CMP). While it has not been literally described elsewhere, such analysis was partly motivated by modern violinmakers and physicists studying Old Italian violins, who were trying to discover spectral relations to sound quality. In this paper, we draw parallels between violins and CMP as far as functionality and spectral characteristics are concerned. Inspired by the de facto standard of violin testing via hammer strikes on the base edge of

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Berney, Needleman David. "Optical design guidelines for spectral splitting photovoltaic systems : a sensitivity analysis approach." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/92072.

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Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014.<br>This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.<br>Cataloged from student-submitted PDF version of thesis.<br>Includes bibliographical references (pages 67-70).<br>Solar power has unmatched ability to provide greater security and reduced environmental impact for the energy sector. Photovoltaic (PV) systems provide the most popular method used today for harnessing this power. However, the costs of t

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Watson, Jonathan M. "Evaluation of spatial-spectral filtering in non-paraxial volume holographic imaging systems." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/44854.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.<br>Includes bibliographical references (leaves 144-148).<br>In this thesis, the properties of transmission-mode volume phase holograms as spatial-spectral filters in optical systems for microscopic medical imaging are evaluated. In experiment, the relationship between the angle of incidence and diffraction efficiency are invesitgated for wavelength-detuned multiplex holograms to establish the limits of the narrow bandwidth lateral field of view. The depth selectivity of the microscope with a volume hol

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Henry, Asegun Sekou Famake. "Molecular dynamics analysis of spectral characteristics of phonon heat conduction in silicon." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/36233.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.<br>Includes bibliographical references (p. 91-95).<br>Due to the technological significance of silicon, its heat conduction mechanisms have been studied extensively. However, there have been some lingering questions surrounding the phonon mean free path and importance of different polarizations. This research investigates phonon transport in bulk crystalline silicon using molecular dynamics and lattice dynamics. The interactions are modeled with the environment dependent interatomic potential (EDIP), w

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Rathod, Chirag. "Examining Plasma Instabilities as Ionospheric Turbulence Generation Mechanisms Using Pseudo-Spectral Methods." Diss., Virginia Tech, 2021. http://hdl.handle.net/10919/102892.

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Turbulence in the ionosphere is important to understand because it can negatively affect communication signals. This work examines different scenarios in the ionosphere in which turbulence may develop. The two main causes of turbulence considered in this work are the gradient drift instability (GDI) and the Kelvin-Helmholtz instability (KHI). The likelihood of the development of the GDI during the August 17, 2017 total solar eclipse is studied numerically. This analysis uses the ``Sami3 is Also a Model of the Ionosphere" (SAMI3) model to study the effect of the eclipse on the plasma density

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El, Tahawy Mohsen Mamdouh Taha <1982&gt. "Modelling Spectral Tunability and Photoisomerization Mechanisms in Natural and Artificial Retinal Systems." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amsdottorato.unibo.it/7829/1/EL_TAHAWY_Mohsen_thesis_to_submit.pdf.

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The photoinduced ultrafast isomerizations of the retinal chromophore (RPSB) in visual rhodopsins are characterized by high speed and efficiency due to conical intersection between the excited and ground electronic states that drives its radiationless decay via an efficient internal conversion. The retinal chromophore displays also a cationic structure and the charge transfer character of its lowest excited bright state makes it sensitive to the environment, namely to the presence of an external electric field. This is in turn able to tune its absorption energy in order to cover the whole visib

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Ellis, Daniel Jared. "Temperature Measurement Using Infrared Spectral Band Emissions From H2O." BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/5488.

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Currently there is no known method for accurately measuring the temperature of the gas phase of combustion products within a solid fuel flame. The industry standard is a suction pyrometer and thermocouple which is intrusive, both spatially and temporally averaging, and difficult to use. In this work a new method utilizing the spectral emission from water vapor is investigated through modeling and experimental measurements. This method was demonstrated along a 0.75m line of sight, averaged over 1 minute in the products of a natural gas flame but has the potential to produce a spatial resolution

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Lundholm, Douglas. "Zero-energy states in supersymmetric matrix models." Doctoral thesis, KTH, Matematik (Avd.), 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-12846.

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The work of this Ph.D. thesis in mathematics concerns the problem of determining existence, uniqueness, and structure of zero-energy states in supersymmetric matrix models, which arise from a quantum mechanical description of the physics of relativistic membranes, reduced Yang-Mills gauge theory, and of nonperturbative features of string theory, respectively M-theory. Several new approaches to this problem are introduced and considered in the course of seven scientific papers, including: construction by recursive methods (Papers A and D), deformations and alternative models (Papers B and C), a

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Cathelain, Marie. "Développement d’un modèle de simulation déterministe pour l’étude du couplage entre un écoulement atmosphérique et un état de mer." Thesis, Ecole centrale de Nantes, 2017. http://www.theses.fr/2017ECDN0001/document.

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La physique de la couche limite atmosphérique en domaine océanique est principalement régie par les processus couplés liés au vent, à l’état de mer local, et à des effets de flottabilité. Leur compréhension reste néanmoins parcellaire et leurs descriptions théoriques et stochastiques sont pour le moins lacunaires, lorsqu’elles ne sont tout simplement pas mises à mal par les rares observations. Dans un contexte d’exploitation croissante de la ressource éolienne offshore, la mise en place de méthodes numériques visant à une description plus fine des propriétés turbulentes de cette couche limite

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