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1
Lawryshyn, Yuri Andrew. « Statics and dynamics of pulp fibres ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ27989.pdf.
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Green, Steven. « Statics and dynamics of mechanical lattices ». Thesis, University of Bath, 2009. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.507762.
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This thesis contributes to the understanding of one dimensional mechanical lattice structures. Structures formed from freely pin jointed rigid links with either vertical or torsional springs at the pivots, or both, are studied under the in uence of an axial load. These studies fall into three parts: static behaviour of a `simple' mechanical system with only vertical springs, dynamic behaviour of this `simple' system, and static behaviour of a compound mechanical lattice with both vertical and torsional springs. The �rst part uses ideas from the �eld of discrete mechanics to derive several discrete boundary value problems that model the static equilibrium states of the `simple' mechanical lattice. This application of discrete mechanics allows us to better understand the relationships between the mechanical system and the discrete boundary value problem used to model it. The resulting discrete boundary value problem is studied in detail and interesting complex behaviour is observed. The study of the dynamic behaviour of the `simple' mechanical lattice concentrates on the existence and stability of time periodic spatially localised solutions called discrete breathers. Discrete breathers are found to exist and to be stable. Also, related solutions called phonobreathers are found to exist and, although the exact phonobreather solutions are unstable, interesting nonlinear dynamic behaviour is observed close to the unstable solutions. Finally, the static behaviour of a new compound mechanical lattice, a discrete version of the strut on a linear foundation, is studied in Chapter 6. We see how the behaviour of two simpler mechanical lattices is manifested in this compound lattice, before presenting analytic and numerical results on the primary, static, bifurcations of this compound lattice. The localised behaviour of the most physically relevant static equilibrium states is also investigated. Extensions to the discrete boundary value problem methods of the earlier chapters are also discussed.
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Shin, Jennifer Hyunjong 1974. « Dynamics and statics of actin assemblies ». Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/27043.
Texte intégralRésumé :
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.Includes bibliographical references (p. 95-101).
The conversion of chemical energy into mechanical forces that powers cell movements is a ubiquitous theme across biology. The acrosome reaction of Limulus sperm is a simple example of such a dynamical transformation where a 60 [mu]m-long crystalline bundle of actin filaments, tightly cross-linked by actin bundling protein scruin, straightens from a coiled conformation and extends from the cell in five seconds. This spring-like mechanism represents a third type of actin-based motility that is distinctly different from the better known polymerization or myosin-driven processes. To identify the basis and mechanism for this movement, we examine the possible sources of chemical and mechanical energy and show that the stored elastic energy alone is sufficient to drive the reaction. We also provide an estimate of the maximum force generated during the uncoiling by stalling the bundle using an agarose gel. Finally, we provide a simple mathematical model that rationalizes the dynamics of uncoiling. Motivated by the very stiff cross-linking in the bundle induced by scruin, we next turn to a model system of scruin mediated cross-linked actin networks where the elastic response is dominated by the properties of actin. While the biological significance of the actin cross-linking proteins is well documented, little is known about how bundling and cross-linking quantitatively affects the microstructure and mechanical properties of actin networks. We quantify the effect of scruin on actin networks using imaging techniques, co-sedimentation assays. multi-particle tracking (MPT), and bulk rheology and demonstrate how a simple entropic elasticity model for a semi-flexible polymer network explains the linear elastic regime of the actin-scruin network.
by Jennifer Hyunjong Shin.
Ph.D.
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Pascual, Blanca. « Uncertainty quantification for complex structures : statics and dynamics ». Thesis, Swansea University, 2012. https://cronfa.swan.ac.uk/Record/cronfa42987.
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Zhao, Lei. « Dynamics and Statics of Three-Phase Contact Line ». Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/102649.
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Wetting, which addresses either spontaneous or forced spreading of liquids on a solid surface, is a ubiquitous phenomenon in nature and can be observed by us on a daily basis, e.g., rain drops falling on a windshield and lubricants protecting our corneas. The study of wetting phenomena can be traced back to the observation of water rising in a capillary tube by Hauksbee in 1706 and still remains as a hot topic, since it lays the foundation for a wide spectrum of applications, such as fluid mechanics, surface chemistry, micro/nanofluidic devices, and phase change heat transfer enhancement. Generally, wetting is governed by the dynamic and static behaviors of the three-phase contact line. Therefore, a deep insight into the dynamics and statics of three-phase contact line at nanoscale is necessary for the technological advancement in nanotechnology and nanoscience. This dissertation aims to understand the dynamic wetting under a molecular kinetic framework and resolve the reconfiguration of liquid molecules at the molecular region of contact line.
Water spreading on polytetrafluoroethylene surfaces is selected as a classical example to study the dynamic behaviors of three-phase contact line. To accommodate the moving contact line paradox, the excess free energy is considered to be dissipated in the form of molecular dissipation. As-formed contact line friction/dissipation coefficient is calculated for water interacting with PTFE surfaces with varying structures and is found to be on the same order of magnitude with dynamic viscosity. From an ab initio perspective, contact line friction is decomposed into contributions from solid-liquid retarding and viscous damping. A mathematical model is established to generalize the overall friction between a droplet and a solid surface, which is able to clarify the static-to-kinetic transition of solid-liquid friction without introducing contact angle hysteresis. Moreover, drag reduction on lotus-leaf-like surface is accounted for as well. For the first time, the concept of contact line friction is used in the rational design of a superhydrophobic condenser surface for continuous dropwise condensation.
We focus on the transport and reconfiguration of liquid molecules confined by a solid wall to shed light on the morphology of the molecular region of a three-phase contact line. A governing equation, which originates from the free energy analysis of a nonuniform monocomponent system, is derived to describe the patterned oscillations of liquid density. By comparing to the Reynolds transport theorem, we find that the oscillatory profiles of interfacial liquids are indeed governed in a combined manner by self-diffusion, surface-induced convection and shifted glass transition. Particularly for interfacial water, the solid confining effects give rise to a bifurcating configuration of hydrogen bonds. Such unique configuration consists of repetitive layer-by-layer water sheets with intra-layer hydrogen bonds and inter-layer defects. Molecular dynamics simulations on the interfacial configuration of water on solid surfaces reveal a quadratic dependence of adhesion on solid-liquid affinity, which bridges the gap between macroscopic interfacial properties and microscopic parameters.Doctor of Philosophy
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Petkov, Theodor. « Statics and dynamics of ellipsoidal particles in laser beams ». Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0878/document.
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Ce travail de thèse est une contribution au projet national AMOCOPS, financé par l’ANR. Le thème central du projet est la diffusion de lumière par des particules de formes complexes et de grandes tailles (plusieurs dizaines de µm au moins), domaine où les méthodes de simulation numérique existantes trouvent leurs limites d’applicabilité. Nous abordons le problème par le biais des effets mécaniques de la lumière, autrement dit les forces et couples créés par la pression de radiation. Etant la conséquence du transfert d’impulsion entre l’onde et la matière, ces effets sont directement liés à la diffusion de lumière. La thèse comprend une partie expérimentale –majoritaire- concernant les réponses mécaniques de particules de polystyrène de forme ellipsoïdale et d’allongement variable sous illumination par un ou deux faisceaux laser. Les cas de faisceaux faiblement focalisés (lévitation optique) et d’un faisceau très fortement focalisé (pincette optique) sont examinés successivement. Nous caractérisons différents types d’équilibre statique, certains d’entre eux non décrits auparavant, obtenus dans les deux géométries. Par ailleurs nous confirmons l’existence de réponses purement dynamiques, où la particule oscille en permanence. Trois nouveaux modes sont observés, deux dans la géométrie lévitation optique et un autre sous pincette optique. Cette étude nous permet de distinguer les oscillations dites de Simpson-Hanna dans le régime linéaire de celles non linéaires mises en évidence avant nous par Mihiretie et al..Les résultats de nos expériences sont comparés à ceux obtenus par les simulations de J.C. Loudet, sur la base de la simple optique géométrique (OG) et limitées à 2 dimensions (2d). Nous montrons que ces simulations permettent de reproduire qualitativement et comprendre physiquement la plupart des comportements observés dans nos expériences. La principale limitation de ces calculs tient à ce que l’OG ignore le caractère ondulatoire de la lumière. Pour faire mieux et aller vers des simulations fiables quantitativement, il faut développer un modèle alliant optique géométrique et optique ondulatoire. C’est la fonction du modèle VCRM (Vectorial Complex Ray Model) développé récemment par K.F. Ren en 2d. Le but du projet Amocops est de mettre au point la version 3d de la méthode et de la valider sur la base d’expériences comme celles que nous avons conduites. La deuxième partie de la thèse est consacrée à la méthode VCRM. Nous en exposons les principes, et nous présentons quelques résultats des travaux en cours avec une version intermédiaire entre 2d et 3d, dite « 2d+ ». Quelques illustrations sont proposées sur des exemples impliquant des sphères et ellipsoïdes de grandes taillesThis work is a contribution to the “AMOCOPS” project, funded by Agence Nationale de la Recherche. AMOCOPS is dedicated to the development of new computation schemes to simulate the light scattering patterns of large complexly shaped particles. Particle sizes are of the order of several 10s of micrometres, which is at the limit, or beyond the capabilities of currently available computation techniques.Our work indirectly deals with light scattering through the corresponding mechanical effects of light. Light scattering is the source of momentum transfer between light and matter, and therefore of the forces and torques acting on the exposed particles. The majority of Part A of this thesis is about the mechanical responses of ellipsoidal polystyrene particles of varying aspect ratios, under illumination by one or two laser beams. We investigate the case of weakly focused beams (optical levitation), and that of a single large aperture beam (optical tweezers). Different types of static equilibria, some of which are new, are observed and characterized in both geometries. We confirm the existence of dynamic states, whereby the particle permanently oscillates within the laser beam(s). Three new oscillation modes are observed, two of them in the conditions of optical levitation, and another one in the optical tweezer geometry. The study allows us to make a distinction between noise-driven oscillations in the linear regime, of the type predicted by Simpson and Hanna, and nonlinear oscillations such as those evidenced prior to this work, by Mihiretie et al..Results from our experiments are compared to simulations by J.C. Loudet, using simple ray-optics (RO) in two dimensions (2D). We show that results from 2D-RO qualitatively match most of our observations, and allow us to physically understand the main mechanisms at work in the observed phenomena. The simulations cannot be quantitatively exact, due to the 2D limitation, and because RO essentially ignores the wave nature of light. In Part B of the manuscript, we present the principles of the Vectorial Complex Ray Model (VCRM), which was recently developed by K.F. Ren in 2d. The goal of AMOCOPS is to develop a full 3D version of VCRM, able to simulate light scattering by particles of any shape with a smooth surface. We explain the basics of the model, as well as the “2D+” version, which is an extension of the basic 2D-VCRM. A few illustrative examples of light scattering patterns computed with 2d+-VCRM for large-sizes spheres and ellipsoids are presented
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Osborn, William R. « Statics and dynamics of interfaces in multi-phase fluids ». Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318759.
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Fukuda, Junichi. « Phase Separation of Liquid Crystalline Polymers -Statics and Dynamics- ». 京都大学 (Kyoto University), 1999. http://hdl.handle.net/2433/157171.
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本文データは平成22年度国立国会図書館の学位論文(博士)のデジタル化実施により作成された画像ファイルを基にpdf変換したものであるKyoto University (京都大学)
0048
新制・課程博士
博士(理学)
甲第7631号
理博第2016号
新制||理||1081(附属図書館)
UT51-99-G225
京都大学大学院理学研究科物理学・宇宙物理学専攻
(主査)教授 小貫 明, 教授 蔵本 由紀, 教授 吉川 研一
学位規則第4条第1項該当
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Greiner, Christopher Mark. « The statics and dynamics of sessile bubbles on inclined surfaces ». Thesis, Massachusetts Institute of Technology, 1985. http://hdl.handle.net/1721.1/15141.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1985.MICROFICHE COPY AVAILABLE IN ARCHIVES AND AERO
Bibliography: leaves 93-94.
by Christopher Mark Greiner.
M.S.
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Bespalov, Anton. « Vortex statics and dynamics in anisotropic and/or magnetic superconductors ». Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0239/document.
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Récemment, les études des propriétés de vortex Abrikosov dans des systèmes fortement anisotropes et magnétiques ont été stimulées par la découverte des supraconducteurs à base de fer et des supraconducteurs ferromagnétiques.Dans cette thèse nous étudions la statique et la dynamique de vortex dans ces systèmes. D’abord, le problème de l'interaction de vortex avec un petit défaut a été examiné dans le cadre de la théorie de Ginzburg-Landau. Le potentiel de pinning pour une cavité cylindrique elliptique a été calculé. D'autre part, la conductivité d'un supraconducteur anisotrope à l'état mixte a été analysée en détail dans le cadre de la théorie de Ginzburg-Landau dépendant du temps.Une partie significative de la thèse est consacrée à l'étude de l'interaction entre lesondes de spin (magnons) et vortex dans les supraconducteurs ferromagnétiques.Nous avons démontré que le spectre de magnon acquiert une structure de bande en présence d'un réseau de vortex idéal. En utilisant les équations phénoménologiques de London et de Landau-Lifshitz-Gilbert, nous avons étudié les réponses ac et dc de vortex dans les supraconducteurs ferromagnétiques. Enfin, nous avons examiné l'état de vortex dans des structures hybrides supraconducteur(S)-ferromagnétique(F)(par exemple, super-réseaux FS) avec une forte dispersion spatiale de la susceptibilité magnétique. Dans ces systèmes l'électrodynamique supraconductrice peut être fortement non locale, qui mène à l'attraction des vortex et à une transition de phase du premier ordre dans la phase de vortexRecently, the studies of the properties of Abrikosov vortices in strongly anisotropicand magnetic media have been stimulated by the discovery of the iron-based andferromagnetic superconductors. In this thesis an analysis of vortex statics anddynamics in such systems has been carried out. Firstly, the problem of vortex pinningon a small defect has been considered. Within the Ginzburg-Landau theory thepinning potential for a cavity in the form of an elliptical cylinder has been derived.Secondly, the flux-flow conductivity of an anisotropic superconductor has beenanalyzed in detail within the time-dependent Ginzburg-Landau theory.A significant part of the thesis is devoted to the study of interplay between spinwaves (magnons) and vortices in ferromagnetic superconductors. We havedemonstrated that the magnon spectrum acquires a Bloch-like band structure in thepresence of an ideal vortex lattice. Using the phenomenological London and Landau-Lifshitz-Gilbert equations, we studied the ac and dc responses of vortices inferromagnetic superconductors. Finally, we investigated the vortex state insuperconductor-ferromagnet (FS) hybrid structures (e. g., FS superlattices) withstrong spatial dispersion of the magnetic susceptibility. In such systems thesuperconducting electrodynamics may be strongly nonlocal, which leads to theattraction of vortices and to a first order phase transition at the lower critical field
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Ma, Mengze. « Modeling Statics and Dynamics Behavior of Ionic Block Copolymer via Coarse-Grained Molecular Dynamics Simulation ». University of Cincinnati / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1613748189579107.
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Ferré, Porta Guillem. « A Monte Carlo approach to statics and dynamics of quantum fluids ». Doctoral thesis, Universitat Politècnica de Catalunya, 2017. http://hdl.handle.net/10803/459067.
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The main objective of the thesis is to study static and/or dynamic properties of a set of quantum fluids by means of quantum Monte Carlo techniques, mainly using the path integral formalism to obtain results both at zero temperature and finite temperature. First, we present briefly some of the more important quantum Monte Carlo methods, and introduce the Path Integral Monte Carlo (PIMC) method, which has been used during all this thesis, as well as the Path Integral Ground State (PIGS), which is an extension of the first at ground state. After introducing the basic formalism, we comment on the approximations needed and provide a comparison between different actions. We also comment on parallelization schemes and advanced sampling techniques.
The first results shown in this thesis are for the phase diagram of a one-dimensional Coulomb gas, which have been obtained using the PIMC method. The phase diagram have been constructed mainly by calculating energetic and structural properties. The obtained results extend previous knowledge of different phases in the one-dimensional Coulomb gas at zero temperature. Our results show the existence of a quantum Wigner crystal regime and a Ideal Fermi gas regime at low temperatures. As temperature increases, we reach a classic Wigner crystal regime and a classical gas.
In the following chapter we show the results of a quasi-one-dimensional para-H2. The aim of this work is to see how the quasi-one-dimensionality affects the Luttinger parameter when comparing it with the pure one-dimensional case. This is done at zero temperature using PIGS. As para-hydrogen is an important candidate to superfluidity, the main idea behind study a quasi-one-dimensional system is to reduce dimensionality in order to soften intermolecular interaction. For that, we try different external potentials to control the opening of the system in two dimensions. Despite an increase in the Luttinger parameter in the various quasi-one-dimensional cases, it still does not reach the values displaying superfluidity.
The next work shown in the thesis is our extensive study of the dynamic structure factor for the 4He. Using Path Integral Monte Carlo, we compute the intermediate scattering function at different temperatures and perform an inversion in order to gain access at the dynamics of the system. Despite the ill-posed problem of this inversion, we obtain results in a qualitative agreement with the experiments and prove that our method of inversion, despite having to yield with inversion problems achieves to obtain better numerical results for 4He at finite temperature than the ones previously reported. In this sense, we provide comparisons with the Maximum Entropy method and with experimental results. The study at different temperatures shows us the dissappearance of the roton peak when we cross T=2.17K from the superfluid regime to the normal fluid. We also observe a kink in the momentum distribution at the superfluid regime that dissappears at higher temperatures, for which does not exist an explanation in the theory.
In the final chapter of the thesis we provide a method to sample complex-time correlation functions whose aim is to obtain better dynamic structure factor functions than the ones obtained via pure imaginary-time correlation functions. This model has already been tested for single-particle systems. Our aim is to test it for multi-particle systems, and to see if we can still recover good results at a reasonable high complex-time when the number of particles is closer to the typical simulation values of real systems. We tested it with particles interacting with an harmonic potential. Despite an increased variance compared with the one-particle case, we obtain good results that allow us to obtain the dynamic structure factor. Comparing the results with ones obtained at pure-imaginary time, we show how the complex-time inversion is superior and provides results closer to the exact ones.L'objectiu principal d'aquesta tesi es l'estudi de propietats estàtiques i dinàmiques de diferents fluids quàntics utilitzant tècniques de Monte Carlo quàntiques, principalment emprant el formalisme de path integrals per obtenir resultats tan a temperatura zero com a temperatura finita. Primer de tot, presentem els mètodes de Monte Carlo quàntics més importants, i introduïm el mètode de Path Integral Monte Carlo (PIMC), que fem servir al llarg de tota la tesi, i el mètode de Path Integral Ground State (PIGS), que es una extensió del primer però a temperatura zero. Després d'introduir el formalisme bàsic, comentem les diferents aproximacions necessàries i aportem una comparació entre elles. També expliquem un possible mètode de paral·lelització i tècniques de mostreig avançat. Els primers resultats que mostrem en aquesta tesi son pel diagrama de fases d'un gas de Coulomb unidimensional, que hem obtingut emprant PIMC. Hem construït el diagrama de fases mitjançant el càlcul de propietats energètiques i estructurals. Els nostres resultats amplien estudis previs que s'havien realitzat pel mateix sistema a temperatura zero. Els nostres resultats mostren l'existència d'un règim de cristall de Wigner quàntic i un d'un gas de Fermi ideal a temperatures baixes. Incrementant la temperatura obtenim un cristall de Wigner clàssic i un gas clàssic. En el següent capítol ensenyem els resultats per un sistema quasi-unidimensional de parahidrogen. L'objectiu d'aquest estudi es veure si la quasi-unidimensionalitat afecta al paràmetre de Luttinger quan el comparem pel cas purament unidimensional. Això ho fem a temperatura zero utilitzant PIGS. Sent el parahidrogen un fort candidat a ser superfluid, la idea principal es veure si reduint la dimensionalitat del sistema podem alleugerir suficient la interacció intermolecular. Per fer-ho, provem diferents potencials externs per controlar l'obertura del sistema en dues de les dimensions. Tot i l'increment del paràmetre de Luttinger respecte al cas unidimensional, aquest no arriba als valors esperats per mostrar superfluïdesa. El següents resultats són del nostre estudi sobre el factor d'estructura dinàmic per 4He. Utilitzant PIMC, calculem la funció de dispersió a diferents temperatures i fem una inversió per tal d'accedir a les propietats dinàmiques del sistema. Tot i la naturalesa de problema mal posat d'aquesta inversió, obtenim resultats qualitativament bons en comparació amb els experimentals, i provem que el nostre mètode d'inversió obté resultats superiors per 4He a temperatura finita que els obtinguts prèviament utilitzant altres mètodes. En aquest sentit, aportem una comparació amb el mètode de màxima entropia i amb resultats experimentals. L'estudi a diferents temperatures ens deixa veure la desaparició del pic del rotó quan creuem T=2.17K des de el règim superfluid al fluid normal. També observem una curvatura estranya en la distribució de moments en el règim de superfluïdesa que desapareix a temperatures més elevades, i pel qual no existeix cap explicació teòrica. Finalment, mostrem un mètode per calcular funcions de correlació en temps complex, l'objectiu del qual es obtenir factors d'estructura dinàmic superiors als obtinguts en temps purament imaginari. Aquest model ha sigut provat amb èxit en sistemes d'una sola partícula. El nostre objectiu es veure si obtenim resultats bons en sistemes amb més partícules, i si el temps complex màxim al que podem accedir no es redueix amb aquest increment. Tot i l'increment en la variança, obtenim bons resultats pel factor dinàmic i, comparant-los amb els obtinguts amb temps imaginari, podem veure com el temps complex ofereix resultats més pròxims als exactes.
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Huang, Chien-Cheng. « Statics, dynamics, and rheological properties of micellar solutions by computer simulation ». Thesis, Universite Libre de Bruxelles, 2007. http://www.theses.fr/2007METZ022S/document.
Texte intégralRésumé :
Les propriétés statiques, dynamiques, rhéologiques et la cinétique de scissions et recombinaisons de micelles linéaires auto-assemblées sont étudiées à l'équilibre et sous-écoulement par simulations sur ordinateur, en utilisant un modèle mésoscopique nouveau. Nous représentons les micelles comme des séquences linéaires de billes browniennes dont l'évolution spatio-temporelle est gouvernée par la dynamique de Langevin. Un algorithme de Monte-Carlo contrôle l'ouverture des liens ou la fusion de deux chaînes par les bouts. Un paramètre cinétique o, qui modélise l'effet d'une barrière le long d'un chemin de réaction, est introduit dans notre modèle. A l'équilibre, nous nous concentrons sur les mécanismes de scission/recombinaison aux temps long et court. Nos résultats montrent que pour les temps plus grands que le temps de vie d'une chaîne moyenne, la cinétique est en accord avec le modèle champ-moyen de Cates. L'étude de fonctions de relaxation macroscopique confirme que nos constantes cinétiques effectives obtenues aux temps longs sont pertinentes pour ces relaxations. Pour la situation hors équilibre, nous étudions les effets du couplage entre un écoulement de cisaillement et la cinétique de scission et recombinaison sur les propriétés structurales et rhéologiques du système micellaire. Nous nous plaçons dans un régime semi-dilué et dynamiquement 'unentangled'. Le paramètre o est choisi de façon à ce que la durée de vie d'une chaîne moyenne soit plus courte que son temps de relaxation de Rouse le plus long. Nos analyses font apparaître une longueur dynamique A, le fiagrnent de chaîne dont la durée de vie TA est égale à son temps de Rouse. Nous trouvons que les propriétés telles que la rhéo-fluidification, l'orientation des chaînes et l'étirement des liens sont des fonctions du taux de cisaillement réduit PA= YT* , alors que la longueur moyenne des micelles est une fonction décroissante du taux de cisaillement, indépendamment de la barrière du processus scission/recombinaisonStatics, Dynamics, and Rheological properties of Micellar solutions by Computer Simulation Statics, dynamics, rheology and scission-recombination kinetics of self-assembling linear micelles are investigated at equlibrium state and under shear flow by computer simulations using a newly proposed mesoscopic model. We model the micelles as linear sequences of Brownian beads whose space-time evolution is governed by Langevin dynamics. A Monte Carlo algorithm controls the opening of a bond or the chain-end fusion. A kinetic parameter o, modelling the effect of a potential barrier along a kinetic path, is introduced in our model. For equilibrium state we focus on the analysis of short and long time behaviors of the scission and recombination mechanisms. Our results show that at time scales larger than the life time of the average chain length, the kinetics is in agreement with the mean-field kinetics model of Cates. By studying macroscopic relaxation phenomena such as the average micelle length evolution after a T-jump, the monomer diffusion, and the zero shear relaxation function, we confirm that the effective kinetic constants found are indeed the relevant parameters when macroscopic relaxation is coupled to the kinetics of micelles. For the non-equilibrium situation, we study the coupled effects of the shear flow and the scissionrecombination kinetics, on the structural and rheological properties of this micellar system. Our study is performed in semi-dilute and dynamically unentangled regime conditions. The explored parameter o range is chosen in order for the life time of the average size chain to remain shorter than its intrinsic (Rouse) longest relaxation time. Central to our analysis is the concept of dynamical unit of size A, the chain fiagrnent for which the life time TA and the Rouse time are equal. Shear thinning, chain orientation and bond stretching are found to depend upon the reduced shear rate P1\=y~A while the average micelle size is found to decrease with increasing shear rate, independently of the height of the barrier of the scission-recombination process
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Biltmo, Anders. « Statics, domain structure and dynamics in the dilute dipolar magnet LiHoF4 / ». Stockholm : Skolan för teknikvetenskap, Kungliga Tekniska högskolan, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-11166.
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Scala, Riccardo. « A variational approach to statics and dynamics of elasto-plastic systems ». Doctoral thesis, SISSA, 2014. http://hdl.handle.net/20.500.11767/3898.
Texte intégralRésumé :
We prove some existence results for dynamic evolutions in elasto-plasticity and delamination. We study the limit as the data vary very slowly and prove convergence results to quasistatic evolutions.
We model dislocations by mean of currents, we introduce the space of deformations in the presence of dislocations and study the graphs of these maps. We prove existence results for minimum problems. We study the properties of minimizers.
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Štekbauer, Hynek. « Vypracování algoritmu a příslušného programového modulu pro statické a dynamické řešení lan na kladkách ». Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227641.
Texte intégralRésumé :
The goal of this master thesis is to develop an algorithm for solving cables on pulleys, which would be more efficient and accurate than existing algorithm used in software RFEM. This algorithm was integrated to the program for static and dynamic analysis of structures, in the form of particular program module. This work also contains examples of using this algorithm. The comparison of expected results with outcomes from the program is presented. The suitability for common practise is examined based on this comparison. The examples showed that the new algorithm for solving of cables on pulleys is more powerful and more accurate than existing solutions and most likely does not has equivalent competition.
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Tröndle, Matthias Verfasser], et Siegfried [Akademischer Betreuer] [Dietrich. « Statics and dynamics of critical Casimir forces / Matthias Tröndle. Betreuer : Siegfried Dietrich ». Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2012. http://d-nb.info/1021923346/34.
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Klotz, Alexander. « Statics and dynamics of DNA in a network of nanofluidic entropic traps ». Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=104815.
Texte intégralRésumé :
A nanofluidic slit embedded with a lattice of square pits was used to entropically trap polymers. DNA in the system was confined to two dimensions and underwent self-assembly into discrete conformational states based on the number of occupied pits. The molecules diffused by undergoing transitions to higher or lower pit-occupancy states and relaxing to their equilibrium state. A statistical mechanical model was used to predict the mean occupancy state as a function of various geometric parameters. Experiments confirm many of the predictions of the model. Regions of parameter space over which a single state dominates were observed, indicating that entropic trapping can be used to create stable self-assembled single polymer conformations. Measurements of diffusion showed it to be geometry dependent, allowing a fine-tuning of diffusivity. The diffusion showed non-monotonic behaviour: local minima corresponding the stable equilibrium states were observed. This demonstrates that the diffusion can be fine-tuned to a local resonance using entropic trapping. The results show that polymers can self-assemble into entropically stable structures, with implications for nanotechnology and biophysics.Nous avons piégé des polymères avec un trellis de fosses nanofluidiques de forme carrée. Nous avons confiné l'ADN en deux dimensions. Il s'est auto-assemblé en états discrets et qui determine du nombre du fosses. Les molecules one sauté et sont tombe es dans un nouvel état, et diffusaient. Nous avons utilisé un modèle mécanique statistique pour une prédire le nombre moyen de fosses. Les expériences confirment le modèle. Nous avons vu des plateaux avec un unique état dominant. Cela signifie que nous pouvons utiliser le piège entropique pour la nanotechnologie : car les structures sont stables. Nous avons mesuré la diffusion. Elle dépend de la géométrie et est non monotonique. Elle a un minimum local vers la region des plateaux. Nous pouvons utiliser le piège entropique pour contrôler la diffusion. Les résultats sont utiles pour la nanotechnologie et biophysique.
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Hömberg, Martin [Verfasser]. « Statics and dynamics of solvent-free models for liquid bilayer membranes / Martin Hömberg ». Aachen : Shaker, 2011. http://d-nb.info/1071528890/34.
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Kaddouri, Abdelhamid. « Infinitesimal and finite deformation analysis of saturated granular materials in statics and dynamics ». Thesis, Heriot-Watt University, 2001. http://hdl.handle.net/10399/496.
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Zandiyeh, A. R. K. « A theoretical and experimental investigation into statics and dynamics of chain cable lifters ». Thesis, University of Sunderland, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234268.
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Moutafis, Christoforos. « Magnetic elements with perpendicular anisotropy : statics and dynamics of magnetic bubbles and vortices ». Thesis, University of Cambridge, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.611377.
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Khdeir, Ahmed Adel. « Analytical solutions for the statics and dynamics of rectangular laminated composite plates using shearing deformation theories ». Diss., Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/49808.
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Latapie, Antoine Nicolas. « Molecular Dynamics Investigation on the Fracture Behavior of Nanocrystalline Fe ». Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/33176.
Texte intégralRésumé :
Crack propagation studies in nanocrystalline alpha-iron samples with grain sizes ranging from 6 to 12 nm are reported at temperatures ranging from 100K to 600K using atomistic simulations. For all grain sizes, a combination of intragranular and intergranular fracture is observed. Mechanisms such as grain boundary accommodation, grain boundary triple junction, grain nucleation and grain rotation are observed to dictate the plastic deformation energy release. Intergranular fracture is shown to proceed by the coalescence of nanovoids formed at the grain boundaries ahead of the crack. The simulations also show that at an atomistic scale the fracture resistance and plastic deformation energy release mechanisms increase with increasing temperature. Finally a softening of the material occurs with decreasing grain size. The elastic properties are found to decrease and the fracture resistance to increase with decreasing grain size.Master of Science
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Nasri, Amin. « On the Dynamics and Statics of Power System Operation : Optimal Utilization of FACTS Devicesand Management of Wind Power Uncertainty ». Doctoral thesis, KTH, Elektriska energisystem, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-154576.
Texte intégralRésumé :
Nowadays, power systems are dealing with some new challenges raisedby the major changes that have been taken place since 80’s, e.g., deregu-lation in electricity markets, significant increase of electricity demands andmore recently large-scale integration of renewable energy resources such aswind power. Therefore, system operators must make some adjustments toaccommodate these changes into the future of power systems.One of the main challenges is maintaining the system stability since theextra stress caused by the above changes reduces the stability margin, andmay lead to rise of many undesirable phenomena. The other important chal-lenge is to cope with uncertainty and variability of renewable energy sourceswhich make power systems to become more stochastic in nature, and lesscontrollable.Flexible AC Transmission Systems (FACTS) have emerged as a solutionto help power systems with these new challenges. This thesis aims to ap-propriately utilize such devices in order to increase the transmission capacityand flexibility, improve the dynamic behavior of power systems and integratemore renewable energy into the system. To this end, the most appropriatelocations and settings of these controllable devices need to be determined.This thesis mainly looks at (i) rotor angle stability, i.e., small signal andtransient stability (ii) system operation under wind uncertainty. In the firstpart of this thesis, trajectory sensitivity analysis is used to determine themost suitable placement of FACTS devices for improving rotor angle sta-bility, while in the second part, optimal settings of such devices are foundto maximize the level of wind power integration. As a general conclusion,it was demonstrated that FACTS devices, installed in proper locations andtuned appropriately, are effective means to enhance the system stability andto handle wind uncertainty.The last objective of this thesis work is to propose an efficient solutionapproach based on Benders’ decomposition to solve a network-constrained acunit commitment problem in a wind-integrated power system. The numericalresults show validity, accuracy and efficiency of the proposed approach.The Doctoral Degrees issued upon completion of the programme are issued by Comillas Pontifical University, Delft University of Technology and KTH Royal Institute of Technology. The invested degrees are official in Spain, the Netherlands and Sweden, respectively.QC 20141028
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Xenikos, Dimitrios George. « Statics and dynamics of the mixed state in pure and aluminum-doped yttrium barium copper oxide high-temperature superconductors / ». The Ohio State University, 1994. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487856076412837.
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Pasha, Hasan G. « Estimation of Static Stiffnesses from Free Boundary Dynamic (FRF) Measurements ». University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1416569956.
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Hömberg, Martin [Verfasser], Marcus [Akademischer Betreuer] Müller, Annette [Akademischer Betreuer] Zippelius et Friederike [Akademischer Betreuer] Schmid. « Statics and dynamics of solvent-free models for liquid bilayer membranes / Martin Hömberg. Gutachter : Marcus Müller ; Annette Zippelius ; Friederike Schmid. Betreuer : Marcus Müller ». Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2011. http://d-nb.info/1043609784/34.
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Šohajek, Jiří. « Analýza vyvrtávacího procesu automatické horizontální vyvrtávačky ». Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2008. http://www.nusl.cz/ntk/nusl-228141.
Texte intégralRésumé :
The object of this dissertation is to analyse a drilling process of an automatic horizontal boring machine the SVD2 for drilling of bearing holes. There were problems with vibrations during drilling process, causing an extreme noise and this dissertation solves them. First of all it was necessary to analyse the vibrations, to examine a machining process and measure machine dynamics and statics. Another task was to compare measured results with mathematical models and after their analysis to design structural and other solutions. The SVD2 machine was designed on the basis of a previous type the SVD. Its conversion to a new one was based on adding of six spindles. As a result a number of drilled bodies was increased from one to four, so a performance was increased four times. That is why there was an original intention to rebuilt the other two spindle machines. To leave the basical parts of the machine without any modification ( such as a reinforcement of a mount and adjusting of a bigger distance of a side linear spindle guideway and a cross linear guideway of a support for clamping devices), would be unsuitable solution, which was confirmed after a measurement and a following analysis.
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Rafie, Christopher A. « Statics and dynamics of cerebral blood ilow is mediated through Hypoxia-inducible factor 2-alpha in the tumor suppressor von Hippel-Lindau knock-out mice ». Diss., [La Jolla] : University of California, San Diego, 2009. http://wwwlib.umi.com/cr/ucsd/fullcit?p1464663.
Texte intégralRésumé :
Thesis (M.S.)--University of California, San Diego, 2009.Title from first page of PDF file (viewed June 15, 2009). Available via ProQuest Digital Dissertations. Includes bibliographical references (p. 13-15).
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Finotti, Gilson. « Cálculo explícito dos torques dos atuadores de um robô paralelo plano empregando o método de Kane ». Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/3/3151/tde-11092008-141036/.
Texte intégralRésumé :
Há mais de uma década os robôs paralelos têm atraído a atenção das comunidades acadêmica e industrial devido às suas vantagens potenciais sobre as arquiteturas predominantes - as seriais. Dentre estas vantagens, pode-se citar a leveza, as elevadas velocidades e acelerações e a capacidade de carga. A aplicação industrial mais promissora para estas arquiteturas alternativas de robôs são as operações \"pega-e-põe\", necessárias nas indústrias alimentícia, farmacêutica e de componentes eletrônicos. Neste trabalho apresenta-se um robô paralelo, concebido com a finalidade de realizar operações \"pega-e-põe\" no espaço bidimensional (plano). O objetivo principal é a análise dinâmica deste mecanismo, empregando o método de Kane, para a determinação dos torques dos atuadores e das forças de reação, causados pelo efeito dinâmico de sua movimentação, quando a garra esteja sujeita a esforços externos e realizando uma trajetória retilínea ou circular em movimento uniforme ou uniformemente variado. Para tanto, desenvolveu-se nesta dissertação a análise cinemática do robô, um estudo de possíveis trajetórias para a garra, o levantamento do espaço de trabalho, bem como a análise dinâmica correspondente. Incluiu-se também diversas simulações para caracterizar melhor suas propriedades.For over a decade parallel robots have attracted the interest from academic and industrial communities due to their potential advantages over the predominant serial architecture. Among these advantages are the lighter weight and higher speeds, accelerations, and load capacity. The most promising industrial application for these alternative architectures are the pick-and-place operations, which are needed in food, pharmaceutical and electronics industries. We show here a parallel robot designed to perform pick-and-place operations in two dimensions , i.e., on a plane. The main goal is the dynamical analysis of this mechanism by means of the Kane method. We determine the torques of the actuators and the reaction forces caused by the dynamical effects of its movement, when its end-effector is subject to external load. The cases of uniform and accelerated movements, with either straight or circular trajectory, are considered. Therefore, in this dissertation we present the kinematics analysis of the robot, an analysis of possible end-effector trajectories, the workspace development, and the corresponding dynamical analysis. A few simulations are also included to better describe its properties.
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Lu, Chang-Tsan. « Atomistic Study of Motion of Twin Boundaries : Nucleation, Initiation of Motion, and Steady Kinetics ». Research Showcase @ CMU, 2013. http://repository.cmu.edu/dissertations/297.
Texte intégralRésumé :
The materials that exhibit martensite transformation have very important applications in engineering, and the microstructures of the materials play a key role foraffecting their mechanical behavior in macroscope. Therefore many attentions havebeen drawn for studying the related problems. This work focuses on the motion oftwin boundaries. Three questions are being asked: how is a twin boundary is nucleated in a homogenous (untwinned) material? After the twin boundary is nucleated,how is its motion initiated? How fast does it move? This study provides an atomisticunderstanding for these three questions.
Linear stability analysis is firstly applied to capture the initiation of motion of atwin boundary. When a twin boundary is about to move, the lowest eigenvalue of thesystem Hessian drops to zero. And the corresponding eigenvector predicts accuratelythe way in which the twin boundary is going to move. The same idea is applied toinvestigate how motion of an irrational twin boundary is initiated. Atomic modelsof irrational twin boundaries are constructed by employment of continuum models,provided that the point group of rotations which relate two variants is extended toany rotations in plane. The zero eigenvectors reveal the complicated behavior ofmotion of irrational twin boundaries.
The problem of nonuniqueness of kinetic relations proposed by Schwetlick andZimmer is solved in a thermoelasticity framework. By calculating the net heat fluxcrossing the phase boundary which is carried by the phonons, a unique kinetic relationcan be determined. Finally, a nonlocal criterion for nucleation of twin boundariesis proposed. By checking the stiffness of each unit cell evaluated with respect to asingle variable that represents the displacement along the unit cell diagonal direction,locations and the orientations of nucleated twin boundaries can be predicted.
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Sammarchi, Enrico. « Dynamic modelling and simulation of a cable-driven parallel robot for rehabilitation applications ». Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/17526/.
Texte intégralRésumé :
The aim of this work, in collaboration with the ROAR Lab of the Columbia University in the city of New York, is to build a simulation model of a new cable-driven parallel robot for rehabilitation applications, being able to compute the effort given by the patient while the system is working on him/her. The model was built on a multi-body dynamic software called Adams, which is able to simulate the behavior of the mechanism.
Some theoretical issues about cable-driven parallel robots will be described, in order to familiarize with the application and introduce the state of the art of the topic. General foundations, dealing with kinematics, statics, dynamics will be detailed and a short introduction to control will be given.
In the second chapter, a brief overview of the state of the art regarding rehabilitation cable-driven robotics will be outlined, first dealing with general applications possible to be found in literature, and then introducing the Columbia University work about this particular topic, with several examples and cutting edge devices.
The third chapter is about the design description of the Stand Trainer, a 8-cable-driven parallel robot used for rehabilitation. Its mechanical system is introduced, while dealing especially with the issue of computing the cable tensions and the way it can be done in terms of sensors positioning. A new way of tension measurement will be explained. It will take the place of the previous one, bringing several advantages to the system.
The last chapter deals with the dynamic simulations on Adams. After having introduced all the simplifications regarding three different models, an accurate description of them will be given and their comparison with the real device will be outlined. The post-process activity will be carried out explaining and discussing the final results.
Finally, different points for future developments will be discussed, showing the novelty of this approach for rehabilitative treatments and applications.
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Mertlík, Jakub. « Valuation and Hedging of Foreign Exchange Barrier Options ». Doctoral thesis, Vysoká škola ekonomická v Praze, 2004. http://www.nusl.cz/ntk/nusl-77859.
Texte intégralRésumé :
The main aim of this thesis is in analyzing and empirically testing the various valuation models and hedging schemes of foreign exchange barrier options and their robustness with respect to changing of market conditions. The purpose of the main empirical section is to get a detailed understanding of the static and dynamic performance of the analyzed models for the barrier options payoff mainly in the extreme market conditions, where we performed a benchmarking of the various hedging schemes. As a by-product, we analyzed the accomplishment of some of the model assumptions in real world setting, and the model dependency of the barrier options.
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Abbs, Brandon Robert. « The temporal dynamics of auditory memory for static and dynamic sounds ». Diss., University of Iowa, 2008. http://ir.uiowa.edu/etd/4.
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Murti, Kamala P. (Kamala Parvathy). « Static and dynamic scheduling in a two station mixed queuing network ». Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/37725.
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Ljungbäck, Jacob. « Characterization of Cascade gearbox for wave energy converter ». Thesis, KTH, Maskinkonstruktion (Inst.), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-182811.
Texte intégralRésumé :
This Master Thesis, written in collaboration with CorPower Ocean, serves as the finalization of the author’s master degree education at KTH (Royal Institute of Technology) Stockholm. The purpose has been to characterize the Cascade gearbox which is used to convert vertical motion induced by waves to rotational motion which powers generators in the company’s future wave energy power plant. The purpose was also to suggest future improvements and shed light on any problems discovered. The method for characterizing the Cascade gearbox was to conduct physical measurements of the load sharing in the inherently overdetermined geometrical design. These data were then used to calibrate a static as well as a dynamic model also developed for this thesis. Focus has been on determining that the novel load sharing method is sufficient and that no gear takes more than the 2,5% overload during max load the gearbox is dimensioned for at any time. Also included in the thesis is an analysis of the tolerances effect on the performance of the Cascade gearbox. Results showed that the current design perform within the expected dimensioning limits. However some unexpected characteristics were discovered after analysis of the results. Because of deliberate geometric decisions half of the gears trail behind initially in one direction causing uneven load sharing and unwanted lateral forces on the rack. Also discovered was the importance of equal stiffness of the flex units, used to divide the load evenly between the gears, since the load sharing factor converges towards values directly proportional to the stiffness ratios in between them. As a conclusion it can be said that although the current design is sufficient, there is still room for improvements which could enhance life expectancy as well as load sharing performance of the Cascade gearbox.Detta examensarbete utfört i samarbete med CorPower Ocean, är det slutgiltiga steget i författarens utbildning på masternivå på KTH (Kungliga Tekniska Högskolan) Stockholm. Syftet med arbetet är att karakterisera en kaskadväxellåda som används för att omvandla vertikal rörelse från vågor till rotation som driver generatorer i företagets framtida vågkraftverk samt att utifrån resultat föreslå möjliga förbättringar och belysa eventuella problem. Den metod som använts för att karakterisera kaskadväxellådan var att via fysiska mätningar, på den testrigg placerad på KTH (Kungliga Tekniska Högskolan) i Stockholm, erhålla data för lastfördelningen i den geometriskt överbestämda konstruktionen. Dessa data användes sedan för att kalibrera en statisk och en dynamisk modell som också utvecklades för det här projektet. Huvudfokus för arbetet har legat i att ta reda på om den konstruktion som används för att fördela lasten mellan kugghjulen fungerar tillfredställande samt att säkerställa att inget kugghjul tar mer än de 2,5% överlast vid fullast växellådan är dimensionerad för vid något tillfälle. Examensarbetet inkluderar även feltoleransers inverkan på lastfördelningen i kaskadväxeln. Resultaten visade att den nuvarande konstruktionen presterar inom de specificerade dimensioneringsintervallen. Några oväntade karaktärsdrag upptäckdes dock vid analys av resultaten. På grund av en avsiktlig geometrisk oregelbundenhet släpade hälften av kugghjulen efter åt ena hållet vilket i sin tur resulterade i en ojämn lastfördelning och oönskade sidokrafter på kuggracken. Flexenheterna som används för att fördela lasten likvärdigt mellan kugghjulen skilde sig åt i styvhet. Den inverkan spridningen av dessa har på lastfördelningen belystes också eftersom lastfördelningen konvergerar mot värden direkt proportionella mot styvhetsförhållandet mellan dem. Slutsatsen från examensarbetet är att den nuvarande konstruktionen, även om den fungerar tillfredställande, lämnar utrymme för förbättringar som potentiellt kan förbättra både livslängd och lastfördelningsprestanda.
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Kuchina, Elena. « Modely analýzy a prognózy insolvence českých podniků ». Master's thesis, Vysoká škola ekonomická v Praze, 2012. http://www.nusl.cz/ntk/nusl-165079.
Texte intégralRésumé :
Different scenarios of the financial situation can take place before the company's bankruptcy. There may be long-term trends in the deteriorating financial situation that indicate the impending corporate bankruptcy, or the bankruptcy may occur unexpectedly, even though the company was ranked among prosperous business units. If the economic situation of the company followed the second scenario, when insolvency was quite predictable, static model, i.e. the model which does not take into account the dynamics of changes in the financial indicators, is a good option to capture the probability of bankruptcy. However, the situation becomes different when the financial indicators fail to show a positive trend throughout some years before the insolvency. In this case, the predictive accuracy of the static model could be increased by a dynamic model by taking into account the fact that the development of the financial indicators in the past periods may affect the company's financial health for the period under consideration.
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Mitra, Dhrubaditya. « Studies of Static and Dynamic Multiscaling in Turbulence ». Thesis, Indian Institute of Science, 2004. https://etd.iisc.ac.in/handle/2005/122.
Texte intégralRésumé :
The physics of turbulence is the study of the chaotic and irregular behaviour in driven fluids. It is ubiquitous in cosmic, terrestrial and laboratory environments. To describe the properties of a simple incompressible fluid it is sufficient to know its velocity at all points in space and as a function of time. The equation of motion for the velocity of such a fluid is the incompressible Navier–Stokes equation. In more complicated cases, for example if the temperature of the fluid also fluctuates in space and time, the Navier–Stokes equation must be supplemented by additional equations. Incompressible fluid turbulence is the study of solutions of the Navier–Stokes equation at very high Reynolds numbers, Re, the dimensionless control parameter for this problem. The chaotic nature of these solutions leads us to characterise them by their statistical properties. For example, statistical properties of fluid turbulence are characterised often by structure functions of velocity. For intermediate range of length scales, that is the inertial range, these structure functions show multiscaling. Most studies concentrate on equal-time structure functions which describe the equal-time statistical properties of the turbulent fluid. Dynamic properties can be measured by more general time-dependent structure functions. A major challenge in the field of fluid turbulence is to understand the multiscaling properties of both the equal-time and time-dependent structure functions of velocity starting from the Navier–Stokes equation. In this thesis we use numerical and analytical techniques to study scaling and multiscaling of equal-time and time-dependent structure functions in turbulence not only in fluids but also in advection of passive-scalars and passive vectors, and in randomly forced Burgers equation.CSIR (INDIA), IFCPAR
Typeset in LATEX by the author
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Mitra, Dhrubaditya. « Studies of Static and Dynamic Multiscaling in Turbulence ». Thesis, Indian Institute of Science, 2004. http://hdl.handle.net/2005/122.
Texte intégralRésumé :
CSIR (INDIA), IFCPARThe physics of turbulence is the study of the chaotic and irregular behaviour in driven fluids. It is ubiquitous in cosmic, terrestrial and laboratory environments. To describe the properties of a simple incompressible fluid it is sufficient to know its velocity at all points in space and as a function of time. The equation of motion for the velocity of such a fluid is the incompressible Navier–Stokes equation. In more complicated cases, for example if the temperature of the fluid also fluctuates in space and time, the Navier–Stokes equation must be supplemented by additional equations. Incompressible fluid turbulence is the study of solutions of the Navier–Stokes equation at very high Reynolds numbers, Re, the dimensionless control parameter for this problem. The chaotic nature of these solutions leads us to characterise them by their statistical properties. For example, statistical properties of fluid turbulence are characterised often by structure functions of velocity. For intermediate range of length scales, that is the inertial range, these structure functions show multiscaling. Most studies concentrate on equal-time structure functions which describe the equal-time statistical properties of the turbulent fluid. Dynamic properties can be measured by more general time-dependent structure functions. A major challenge in the field of fluid turbulence is to understand the multiscaling properties of both the equal-time and time-dependent structure functions of velocity starting from the Navier–Stokes equation. In this thesis we use numerical and analytical techniques to study scaling and multiscaling of equal-time and time-dependent structure functions in turbulence not only in fluids but also in advection of passive-scalars and passive vectors, and in randomly forced Burgers equation.
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Plourde, Lise. « La dynamique sociale et économique de la réingénierie des processus chez Desjardins : le cas de la caisse populaire de Mistassini / ». Thèse, Chicoutimi : Université du Québec à Chicoutimi, 1999. http://theses.uqac.ca.
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Toshniwal, Smita. « Dynamic Mobility of Multiple Base Stations in an Event driven Static Wireless Sensor Network ». University of Cincinnati / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1249666898.
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Kim, Kang. « Static and dynamic properties of simple liquids and glasses : Molecular dynamics and density functional theory ». 京都大学 (Kyoto University), 2003. http://hdl.handle.net/2433/148781.
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Blood, Ellery A. « From Static to Dynamic Electric Power Network State Estimation : The Role of Bus Component Dynamics ». Research Showcase @ CMU, 2011. http://repository.cmu.edu/dissertations/57.
Texte intégralRésumé :
This thesis addresses the challenge of accurately and robustly estimating the network state on an electric power network despite its large size, infrequent measurement updates, and high likelihood of corrupted data. This is especially important as electrical transmission operators are increasingly being asked to operate the networks at their maximum allowable capacity. Accurate knowledge of the state is necessary to ensure adequate margin to these operating limits should a fault occur.
This thesis provides the following contributions. 1. Models describing the dynamics of slow machinery attached to and coupled via the electric power network were used to allow dynamic state estimation. 2. The detail of the coupled dynamic network model was evaluated to determine the level of modeling complexity required to achieve significant state estimation performance gains. 3. Improvements to bad data detection and identification by using information from the dynamic state estimator were demonstrated and evaluated. 4. The improvements to network static observability were discussed and evaluated.
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Mudigonda, Ashwin. « Static and Dynamic Characterization of Ionic Polymer Metal Composites - 'Artificial Muscles' ». Ohio : Ohio University, 2006. http://www.ohiolink.edu/etd/view.cgi?ohiou1142538201.
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Trojanová, Lenka. « Statická a dynamická analýza skleněných konstrukcí ». Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2014. http://www.nusl.cz/ntk/nusl-226648.
Texte intégralRésumé :
Glass and the glass elements found thein way into almou all area sof human aktivity thanks to technological advances of the last 20 years. The are of construction i sof course no exeption, quite the contrary. These days it is difficult to imagine building without the glass element, whether it is a part of the interior or exterior. Yet the theory on this issue is at a very low level in the Czech Republic. The content of my work is static and dynamic analysis of structures of glass, when it is applied in practice, it will save money.
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Čáslavová, Sandra. « Statická a dynamická analýza mostní konstrukce ». Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2018. http://www.nusl.cz/ntk/nusl-371895.
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The aim of this thesis is to conduct static and dynamic computations for selected bridge in the Moravian region, specificaly in the surroundings of Olomouc. All calculations will be made by selected software and verified by manual reckon. The bridge is intended for pedestrian traffic and connects left and right side of the river underneath.
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Yaghi, Anas H. « Static and dynamic brittle fracture ». Thesis, University of Nottingham, 1993. http://eprints.nottingham.ac.uk/11786/.
Texte intégralRésumé :
The project examined the static and dynamic fracture mechanics of brittle materials. Destructive testing was performed on brittle, elastic, isotropic and homogeneous epoxy resin specimens made of Araldite CT-200 with Hardener HT-907. Three types of specimen were investigated, namely the three point bend (3PB) beam, the compact mixed-mode (CMM) specimen and the pressure tube. The 3PB and CMM specimens contained both narrow notches and real cracks. The pressure tubes included semi-circular notches. The real cracks were obtained by controlled fatiguing. The research involved the evaluation of the static mode-I and mode-II real and apparent critical stress intensity factors. The fracture surfaces and the phenomenon of crack branching were studied. The dynamic mode-I stress intensity factor was obtained at the inception of crack instability and also at branching. The concept of the existence of a unique relationship between the dynamic stress intensity factor and the instantaneous crack velocity was addressed. The possibility of modelling cracks in structural components by using cast shim notches in epoxy resin was discussed. The modelling of the static behaviour was proposed to be accurate and relatively easy. The dynamic behaviour would be approximately modelled; therefore suggestions on how to improve the dynamic modelling of propagating cracks were recommended, paying particular attention to the branching process and the instantaneous crack velocity. In addition to the experimental work, finite element analysis was conducted for the 3PB and CMM specimens containing narrow notches. It was shown that the specific geometry and loading conditions were unimportant and that the loading was conveniently characterised by the stress intensity factors for an equivalent crack. A method was devised which provided a relatively cheap and efficient means of determining stress concentration factors for what might appear to be complex geometries and loading conditions.
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Rushton, Matthew V. « Static and dynamic type systems ». Diss., Connect to the thesis Connect to the thesis, 2004. http://hdl.handle.net/10066/1483.
Texte intégral
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Horenský, Martin. « Dynamická kompenzace ». Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2014. http://www.nusl.cz/ntk/nusl-220932.
Texte intégralRésumé :
This master’s thesis is focusing on compensation of reactive power, especially on creating demonstrative model of static var compensation unit (SVC). Main topic of thesis is to apply this device for fast balancing dynamic conversions of recieved reactive power. In theoretical part is described suitable method for determination of instantaneous power. Next, there is basic description of all means used for compensation of reactive power and detailed description of the SVC compensator. Practical part includes design of compensation unit and control program in LabVIEW. The pq theory is implemented for detection instantaneous power. The results of validating functionality of compensator are presented in the last part of thesis.