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1
Afolabi, Jamiu Lanre. „The performance of a static coal classifier and its controlling parameters“. Thesis, University of Leicester, 2012. http://hdl.handle.net/2381/11078.
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In power generation from solid fuel such as coal-fired power plants, combustion efficiency can be monitored by the loss on ignition (LOI) of the pulverised fuel. It is the role of the pulveriser-classifier combination to ensure pulverised fuel delivered to the burners is within the specified limits of fineness and mass flow deviation required to keep the LOI at an acceptable level. However, government imposed limits on emissions have spurred the conversion of many coal fired power plants to convert to the use of Low NOx Burners. To maintain good LOI or combustion efficiency, the limits of fineness and mass flow deviation or inter-outlet fuel distribution have become narrower. A lot of existing pulveriser units cannot operate efficiently within these limits hence retrofits of short term solutions such as orifice balancing and classifier maintenance has been applied. The work performed in this thesis relates to an investigation into coal classifier devices that function to control fineness and inter pipe balancing upstream of the burner and downstream of the pulverisers. A cold flow model of a static classifier was developed to investigate the flow characteristics so that design optimisations can be made. Dynamic similarity was achieved by designing a 1/3 scale model with air as the continuous phase and glass cenospheres of a similar size distribution as pulverised fuel, to simulate the coal dust. The rig was operated in positive pressure with air at room temperature and discharge to atmosphere. The Stokes number similarity (0.11-prototype vs. 0.08-model) was the most important dimensionless parameter to conserve as Reynolds number becomes independent of separation efficiency and pressure drop at high industrial values such as 2 x 10 4 Hoffman, 2008). Air-fuel ratio was also compromised and an assumption of dilute flow was made to qualify this. However, the effect of air fuel ratio was ascertained by its inclusion as an experimental variable. Experiments were conducted at air flow rates of 1.41-1.71kg/s and air fuel ratios of 4.8-10 with classifier vane angle adjustment (30°- 60°) and inlet swirl umbers (S) of 0.49 – 1. Radial profiles of tangential, axial and radial velocity were obtained at several cross sections to determine the airflow pattern and establish links with the separation performance and outlet flow balance. Results show a proportional relationship between cone vane angle and cut size or particle fineness. Models can be derived from the data so that reliable predictions of fineness and outlet fuel balance can be used in power stations and replace simplistic and process simulator models that fail to correctly predict performance. It was found that swirl intensity is more significant a parameter in obtaining balanced flow at the classifier outlets than uniform air flow distribution in the mill. However the latter is important in obtaining high grade efficiencies and cut size. The study concludes that the static classifier can be further improved and retrofit-able solutions can be applied to problems of outlet flow imbalance and poor fineness at the mill outlets.
2
Hanni, M. (Matti). „Static and dynamic NMR properties of gas-phase xenon“. Doctoral thesis, University of Oulu, 2011. http://urn.fi/urn:isbn:9789514294570.
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Abstract
This thesis presents computational studies of both the static and dynamic parameters
of the nuclear magnetic resonance (NMR) spectroscopy of gaseous xenon.
First, state-of-the-art static magnetic resonance parameters are computed in small
xenon clusters by using methods of quantum chemistry, and second, time-dependent
relaxation phenomena are investigated via molecular dynamics simulations
at different experimental conditions. Based on the underlying quantum and
classical mechanics concepts, computational methods represent a procedure complementary
to experiments for investigating the properties of atoms, molecules,
clusters and solids.
Static NMR spectral parameters, chemical shift, shielding anisotropy and asymmetry
parameter, nuclear quadrupole coupling, and spin-rotation coupling, are
calculated using different electronic structure methods ranging from the uncorrelated
Hartree-Fock method to correlated second-order Møller-Plesset many-body
perturbation, complete/restricted active space multiconfiguration self-consistent
field, and to coupled-cluster approaches. The bond length dependence of these
properties is investigated in the xenon dimer (Xe2). A well-characterized property
in experimental NMR, the second virial coefficient of nuclear shielding, is
theoretically calculated by a variety of methods and convincingly verified against
experimental findings. Here, it is mandatory to include effects from special relativity
as well as electron correlation. As a side result, a purely theoretical potential
energy curve for Xe2, comparable to best experimental ones, is calculated.
A pairwise additive scheme is established to approximate the NMR properties in
differently coordinated sites of xenon clusters Xen (n = 2 - 12). Especially the
pairwise additive chemical shift values are found to be in close agreement with
quantum-chemical results and only a small scaling factor close to unity is needed
for the correct behavior. Finally, a dynamical magnetic resonance property, the
experimental nuclear spin-lattice relaxation rate R1 of monoatomic Xe gas due to
the chemical shift anisotropy (CSA) mechanism is validated from first principles.
This approach is based on molecular dynamics simulations over a large range of
temperatures and densities, combined with the pairwise additive approximation
for the shielding tensor. Therein, the shielding time correlation function is seen
to reflect the characteristic time scales related to both interatomic collisions and
cluster formation. For the first time, the physics of gaseous xenon is detailed in
full in the context of CSA relaxation.
3
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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4
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.
5
Shin, Jennifer Hyunjong 1974. „Dynamics and statics of actin assemblies“. Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/27043.
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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.
6
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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7
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
8
Grachek, Adam. „Individualized Pedestrian and Micromobility Routing Incorporating Static and Dynamic Parameters“. Thesis, Linköpings universitet, Kommunikations- och transportsystem, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-177784.
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This project seeks to demonstrate routing optimization that would allow pedestrian and micromobility user groups to select and prioritize different route features according to their preferences. Through the creation of a routing demonstrator that considers both static and dynamic parameters in the form of pavement quality, elevation climb, travel time, and air quality, along with user-specified weights for their prioritization of each of these parameters, a number of routes were created and mapped to qualitatively compare against routes representing only a shortest path.Examensarbetet är utfört vid Institutionen för teknik och naturvetenskap (ITN) vid Tekniska fakulteten, Linköpings universitet
9
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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10
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
11
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
12
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.
13
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
14
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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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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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.
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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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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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Tröndle, Matthias Verfasser], und 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.
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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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Bapat, Amey Vivek. „Influence of Bridge Parameters on Finite Element Modeling of Slab on Girder Bridges“. Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/36105.
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The present study is part of the Long Term Bridge Performance Program (LTBP) funded by the Federal Highway Administration. The objectives of this program are to create a comprehensive database of quantitative information of the long-term performance of selected pilot bridges and to develop a methodology to assess bridge performance. Finite element (FE) modeling of the pilot bridges is an intrinsic part of the LTBP program and is intended to not only assist with instrumentation decisions, but also to provide further insight into the behavior of these bridges, which cannot be achieved solely from field testing of the bridges. This thesis provides a comprehensive study of a plethora of issues associated with the development of reliable and accurate FE models of bridges.
The first objective of this investigation was to develop reliable finite element models with a variety of levels of refinement and to study the effect of the inclusion of various bridge parameters in the model, such as bridge skew, degree of composite action, thermal gradient and level of support restraint, on the response of bridges. First, the suitability of different modeling techniques and of elements used to model the primary bridge components was assessed using simple models for which analytical solutions are readily available. From these studies, it was concluded that shell elements are adequate to model the bridge deck, and beam and shell elements are both satisfactory to model the bridge girders. From the dynamic analyses of theWildcat Creek River Bridge and the Colquitz River Bridge, flexural modes of vibration were found to be highly sensitive to support restraints and to how the guardrails were modeled and less sensitive to the inclusion of bracing and thermal gradients in the model. The finite element models using extreme boundary conditions were successful in bracketing the field response. The factors identified from these analyses were considered in the analysis of the Virginia pilot bridge. Different support restraints, and the inclusion of skew and level of composite action in the model had noticeable impact on both the static and dynamic responses of the bridge. The results from these analyses were used to assist with instrumentation decisions prior to field-testing. The developed model will also be used to help researchers further understand the bridgeâ s behavior and to help explain a variety of phenomena observed in the field.Master of Science
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Sandell, Viktor. „Extraction of Material Parameters for Static and Dynamic Modeling of Carbon Black Filled Natural Rubbers“. Thesis, Luleå tekniska universitet, Materialvetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-65583.
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Volvo Car Corporation (Volvo Cars) develops powertrain mounting systems that uses components made up largely of filled rubber materials. The development of such components is today relying on external suppliers to design components based on requirements set by Volvo. To reduce costs and lead-time in the development process the possibility of in-house design of such components at Volvo Cars is being investigated. For this to be possible, knowledge must be built concerning modelling the mechanical properties of rubber materials. As part of this a parameter extraction method for modelling of filled rubber materials intended for finite element use has been developed in this project. Both a simple static model fitting procedure and a more complex dynamic model fitting procedure are detailed. Mechanical testing of four filled natural rubber materials with varying hardnesswas carried out at the facilities of Volvo Cars and recommendations have been made regarding the limits of the equipment and the specific test body geometry used. It was found that the lower limit for dynamic testing in regards to displacement amplitude is 0.02 mm. The highest frequency recommended is dependent on the material hardness but a higher limit of 200 Hz is recommended for the softest material investigated. The upper limit was found to be necessary due to inertia effects in the material. The models used to describe the static behaviour were hyperelastic phenomenological models independent on the second invariant such as the Yeoh and the linear neo-Hookean models. The dynamic model used the overlay method to capture therate and amplitude dependent properties of filled rubber. A generalized viscoelastic-elastoplastic rheological model using Maxwell and friction elements in parallel with alinear elastic element was presented and used. These were limited to having maximumfive of each element and no attempts at minimizing this number was made in this work.The dynamic model was fitted to experimental data using a minimization procedure focusing on dynamic modulus and damping at a range of frequencies and strain amplitudes.The proposed fitting procedure is a three segment loop in which FE simulationsof the experimental data is used as both a correction and a validation tool.Model validation showed good correlation of the fitted model to measured databefore correction was attempted. The correction step did not improve the model qualityand the reason for this was identified as poor post-processing. The proposed method together with lessons learned during the course of the project will be of importance for the future in-house development of rubber components at Volvo Cars.
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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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Algassem, Omar. „Parameters Affecting the Blast Performance of High Strength Fibre Reinforced Concrete Beams“. Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/35022.
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A limited number of studies have been conducted in the literature in order to investigate the behaviour of high-strength fibre-reinforced concrete (HSFRC) structural components subjected to blast loads. This study summarizes the results of a research program investigating the potential of using steel fibres to improve the blast performance of high-strength reinforced concrete beams. As part of the experimental investigation twenty beams were tested, including nine beams tested under static four-point bending, and eleven beams tested under dynamic blast loads using a shock-tube. Parameters considered in the study include the effect of concrete strength, steel fibres, fibre content, fibre type, longitudinal reinforcement ratio, and presence of shear reinforcement. All beams in the study have identical dimensions, with a cross-section of 125 x 250 mm and length of 2440 mm. To manufacture the specimens, two beams were cast with normal-strength self-consolidate concrete (SCC), with a specified strength of 50 MPa, while the remaining beams were cast with either plain or fibre-reinforced high-strength concrete having a compressive strength which varied between 95-110 MPa. The steel fibre content in the HSFRC beams varied between 0.5 and 1.0%, by volume of concrete. To investigate the effect of reinforcement ratio (ρ), the beams were reinforced with 2-#4 (American size) bars, 2-15M bars or 2-20M bars (ρ = 1.02%, 1.59%, and 2.41%, respectively). The majority of the plain concrete beams had transverse reinforcement which consisted of 6 mm stirrups arranged at a spacing of 100 mm in the shear spans, while most of the HSFRC beams were built without stirrups. The results indicate that all the parameters in this study (reinforcement ratio, presence of stirrups, concrete strength, steel fibres, fibre content and fibre type) affected the static and blast response of the beams, however, the results demonstrate that steel fibres have a more remarkable effect when compared to the other parameters. The provision of fibres is found to improve the blast performance of the HSC beams by increasing shear capacity, reducing maximum and residual mid-span displacements, reducing blast fragments and increasing damage tolerance.
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Boberg, Frida. „Simulation of dynamic and static behavior of an electrically powered lift gate“. Thesis, Linköping University, Department of Electrical Engineering, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-11627.
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Continental Automotive Systems is a German company that develops control systems for different applications in cars. A control system for electrically powered lift gates that are opened or closed on the driver’s command is one of the products developed. The drive system itself is composed of a spindle that is driven by a DC-motor over a gear and a spring. When developing the control system it is convenient to use a simulation model instead of having to implement it on the system every time. The simulation analytically describes how the system is behaving.
In this thesis a simulation model of a drive system and a lift gate is developed and evaluated. The model parameters are estimated using System Identification Toolbox in Matlab.
Continental Automotive Systems är ett tyskt företag som utvecklar styrsystem för olika tillämpningar i bilar. Bland annat utvecklas ett styrsystem till eldrivna bakluckor som öppnas och stängs av föraren per knapptryck. Själva drivanordningen består av en skruv som drivs av en likströmsmotor över en utväxling och en fjäder. Då man vill utveckla styrsystemet utan att behöva implementera det på systemet varje gång är en simuleringsmodell av drivanordningen och luckan ett bra hjälpmedel. Denna simuleringsmodell kan då analytiskt beräkna hur systemet uppför sig.
I detta examensarbete har en simuleringsmodell av en drivanordning med tillhörande lucka utvecklats och utvärderats. Modellparametrarna estimerades med hjälp av System Identification Toolbox i Matlab.
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Faez, Elias Feras. „Estimation of Inertial Parameters for Automatic Leveling of an Underwater Vehicle“. Thesis, Linköpings universitet, Reglerteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-140188.
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The use of underwater systems has grown significantly, and they can be used both for military and civilian purposes. Many of their parts are replaceable. An underwater vehicle can be equipped with different devices depending on the taskit should carry out. This can make the vehicle unbalanced, which means that the demand for balancing systems will increase in line with the increasing use of underwater systems. The goal of the thesis is to deliver a method for balancing based on parameters estimated both in static and dynamic operation. The parameters define a nonlinear physical model that can describe the underwater vehicle in different environments and conditions. The main idea in the proposed method for parameter estimation based on static operation data is to solve equilibrium equations when the on-board control system is used to maintain two different orientations. The balancing can then be done by solving an optimisation problem that gives information about where additional weights or float material should be installed. The static parameter estimation has been evaluated successfully in simulations together with three ways of solving the balancing problem. The dynamic parameter estimation has also been evaluated in simulations. In this case, the estimated parameters seem to have the same sign as the true ones but it seems difficult to obtain accurate estimates of some of the parameters. However, the total dynamic model was good except the prediction of the vertical movements. In particular, the model could explain the rotations of the vehicle well. The reason for the worse performance for the vertical movements might be some difficulties when generating suitable excitation signals. The work done by Feras Faez Elias in connection to this master thesis made a contribution to a patent application that Saab AB has filed where Feras Faez Elias was one of the inventors.
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Mader, Daniel. „Měření výkonových parametrů zážehových motorů“. Master's thesis, Česká zemědělská univerzita v Praze, 2016. http://www.nusl.cz/ntk/nusl-259049.
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This thesis describes the various methods for measuring the performance parameters of petrol engines and on the selected engine (car) evaluate their accuracy with regard to the economic complexity of the methods.
In the first part of this thesis is described construction of combustion engines, explained the importance of individual performance parameters (power, torque, specific fuel consumpti-on) and characteristics combustion engines. This section, however, is focused on the issue of performance measurement, using both static and dynamic methods of measurement. The second part examined the various methods of measurement in practice on selected engine (car) with an assessment of their advantages and disadvantages and the financial cost of the-ir implementation.
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Dvořák, Marek. „Metody měření výkonových parametrů vznětových motorů“. Master's thesis, Česká zemědělská univerzita v Praze, 2016. http://www.nusl.cz/ntk/nusl-259132.
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The thesis deals with the performance measurement of tractor engine through four used different methods. In the first theoretical part of thesis is analysis engine design with its main groups and the second part explains methods of measuring performance and measuring equipment. In the practical part of thesis is the explained methodology of applied methods of measurement, together with their evaluation. The first applied method is performance measurement on the dynamometer, the second method is measurement of these parameters during free acceleration, the third method is measurement of parameters during free acceleration with load and fourth method is measurement of parameters using GPS. In conclusion of this part is to compare the results of each used measurement methods between themselves and the conclusions drawn from it.
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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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Köcher, Simone Swantje [Verfasser], Josef [Akademischer Betreuer] Granwehr und Arne [Akademischer Betreuer] Lüchow. „Simulation of static and dynamic magnetic resonance parameters for solid mixed conductors / Simone Swantje Köcher ; Josef Granwehr, Arne Lüchow“. Aachen : Universitätsbibliothek der RWTH Aachen, 2019. http://d-nb.info/1193734746/34.
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Ayad, Mohammad. „Homogenization-based, higher-gradient dynamical response of micro-structured media“. Electronic Thesis or Diss., Université de Lorraine, 2020. http://www.theses.fr/2020LORR0062.
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Une approche dynamique discrète (DDM) est proposée dans le contexte de la mécanique des poutres pour calculer les caractéristiques de dispersion des structures périodiques. Cette démarche permet de calculer les caractéristiques de dispersion de milieux périodiques unidimensionnels et bidimensionnels. Il est montré qu’un développement d'ordre supérieur suffisamment élevé des forces et des moments d’éléments structuraux est nécessaire pour décrire avec précision les modes de propagation d’ordre supérieur. Ces résultats montrent dans l’ensemble que les calculs des caractéristiques de dispersion de systèmes structurels périodiques peuvent être abordés avec une bonne précision par la dynamique des éléments discrets. Les comportements non classiques peuvent être capturés non seulement par une expansion d'ordre supérieur mais aussi par des formulations à gradient supérieur. Nous calculons ainsi les paramètres constitutifs macroscopiques jusqu'au deuxième gradient du déplacement en utilisant deux formulations différentes, soit selon une méthode d'homogénéisation dynamique à gradient supérieur (DHGE) prenant en compte les effets de micro-inertie, ou alternativement selon le principe de Hamilton. Nous analysons ensuite la sensibilité des termes constitutifs du second gradient aux paramètres microstructuraux pour des matériaux composites à microstructure périodique de type laminés. En plus, on montre que les modèles du deuxième gradient formulés à partir de l'énergie interne totale en tenant compte des termes de gradient d'ordre supérieur donnent la meilleure description du propagation d’onde à travers ces milieux. On analyse les contributions d'ordre supérieur et de micro-inertie sur le comportement mécanique de structures composites en utilisant une méthode d'homogénéisation dynamique d'ordre supérieur qui intègre les effets de micro-inertie. Nous calculons la réponse effective statique longitudinale à gradient d’ordre supérieur, en quantifiant la différence relative par rapport à la formulation classique de type Cauchy qui repose sur le premier gradient du déplacement. Nous analysons ensuite les propriétés de propagation d’ondes longitudinales en termes de fréquence propre de composites, en tenant compte de la contribution de la micro-inertie. La longueur interne joue un rôle crucial dans les contributions de micro-inertie avec un effet substantiel pour les faibles valeurs de longueur interne, et qui correspond à une large gamme de matériaux utilisés en ingénierie des structures. La méthode d’homogénéisation développée montre un effet de taille important pour les modules élastiques homogénéisés d’ordre supérieur. Par conséquent, nous développons une formulation indépendante de la taille qui est basée sur des termes de correction liée aux moment quadratique. Dans ce contexte, on analyse l’influence des termes de correction sur le comportement statique et dynamique de composites à inclusionA discrete dynamic approach (DDM) is developed in the context of beam mechanics to calculate the dispersion characteristics of periodic structures. Subsequently, based on this dynamical beam formulation, we calculate the dispersion characteristics of one-dimensional and two-dimensional periodic media. A sufficiently high order development of the forces and moments of the structural elements is necessary to accurately describe the propagation modes of higher order. These results show that the calculations of the dispersion characteristics of structural systems can be approached with good accuracy by the dynamics of the discrete elements. Besides, non-classical behaviors can be captured not only by higher order expansion but also by higher gradient formulations. To that scope, we develop a higher gradient dynamic homogenization method with micro-inertia effects. Using this formulation, we compute the macroscopic constitutive parameters up to the second gradient, using two distinct approaches, namely Hamilton’s principle and a total internal energy formulation. We analyze the sensitivity of the second gradient constitutive terms on the inner material and geometric parameters for the case of composite materials made of a periodic, layered microstructure. Moreover, we show that the formulations based on the total internal energy taking into account higher order gradient terms give the best description of wave propagation through the composite. We analyze the higher order and micro-inertia contributions on the mechanical behavior of composite structures by calculating the effective static and dynamic properties of composite beams using a higher order dynamic homogenization method. We compute the effective longitudinal static response with higher order gradient, by quantifying the relative difference compared to the classical formulation of Cauchy type, which is based on the first gradient of displacement. We then analyze the propagation properties of longitudinal waves in terms of the natural frequency of composite structural elements, taking into account the contribution of micro-inertia. The internal length plays a crucial role in the contributions of micro-inertia, which is particularly significant for low internal length values, therefore for a wide range of materials used in structural engineering. The developed method shows an important size effect for the higher gradients, and to remove these effects correction terms have been incorporated which are related to the quadratic moment of inertia. We analyze in this context the influence of the correction terms on the static and dynamic behavior of composites with a central inclusion
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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.
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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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Quispe, Ledesma Fredy. „Análisis y diseño estructural comparativo con la norma sismo resistente E.030-2014 vs. E.030-2003 de un edificio multifamiliar de 5 pisos en Distrito de Surquillo“. Bachelor's thesis, Universidad Ricardo Palma, 2015. http://cybertesis.urp.edu.pe/handle/urp/1337.
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El presente trabajo tiene por objetivo Realizar el diseño estructural con el proyecto de norma de diseño sismo resistente E.030-2014 y compararla con la a la E.030-2003 para comprobar sus ventajas e incidencia en el diseño de
un edificio de cinco pisos destinados a multifamiliar, esta comparación se realizará durante el análisis sísmico del edificio, aplicando y comparando los parámetros de cada una de estas norma simultáneamente, para de esa manera comparar los resultados de las solicitaciones que producen a la hora de realizar el diseño estructural , también verificar en que porcentaje varían estas dos demandas y si este influye económicamente en la concepción de los planos estructurales del proyecto así como la influencias de los nuevos parámetros en el comportamiento sísmico del edificio en conjunto.
La metodología a utilizar para el desarrollo de esta tesis es del tipo cuantitativo nivel descriptivo y de método diseño experimental y explicativo, longitudinal y prospectivo. .
El proyecto que se utilizara para la comparación y el diseño estructural, se ubica en la ciudad de Lima en el distrito de Surquillo, sobre un terreno de 503.63m2 de área. El suelo está constituido de la grava típica de la ciudad de Lima, con un esfuerzo admisible (Capacidad Portante) del terreno de 4Kg. /cm2 a 1.30 m. de profundidad.
Después haber realizar toda las etapas de diseño y enfocándonos en el análisis sísmico comparativo con las dos versiones de la norma E.030 obtenemos resultados muy próximos la diferencia de demanda sísmica está en el orden del 1%-6% y por eso a la hora de diseñar con los resultados de cualquiera de las dos versiones de la norma E.030, no causa problema desde el punto de vista económico. También se observa que hay parámetro que limitan la irregularidad en el edificio y mejoran el comportamiento sísmico de este.
Se finaliza con la elaboración de los planos estructurales de todo el edificio que es uno de los objetivos fundamentales de esta investigación.
This paper aims to Perform structural design with the draft of E.030-2014 earthquake resistant design and compare it with the E.030-2003 to check their benefits and impact on design
a five-story building intended for multifamily, this comparison will take place during the seismic analysis of the building, using and comparing the parameters of each of these standards simultaneously, to thereby compare the results of the stresses that occur when making structural design, also check that these two percentage varying demands and economically if it influences the design of structural drawings of the project as well as the influences of the new parameters on the seismic behavior of the building as a whole.
The methodology used to develop this thesis is the quantitative level and descriptive and explanatory experimental, longitudinal and prospective design method. .
The project to be used for comparison and structural design, is located in the city of Lima in the district of Surquillo, on a land of 503.63m2 area. The floor is made of the typical gravel Lima, with allowable stress (bearing capacity) 4 kg terrain. / Cm2 to 1.30 m. deep.
After having performed all stages of design and focusing on the comparative seismic analysis with two versions of the E.030 standard we get very close results the difference of seismic demand is in the order of 1% -6% and that at the time design with the results of either the E.030 standard versions, causes no problem from the economic standpoint. It is also noted that there are parameters that limit the irregularity in the building and improve the seismic performance of this.
It ends with the development of structural plans of all the building that is one of the key objectives of this research.
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Hwang, Ho-yon. „Identification methods for physical parameters in structures“. Diss., Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/15652.
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Hatch, Nicholas Adam. „Radar based estimation of asymmetric target inertial parameters“. Link to electronic thesis, 2006. http://www.wpi.edu/Pubs/ETD/Available/etd-041406-103944/.
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Dissertation (Ph.D.)--Worcester Polytechnic Institute.Keywords: estimation, radar, asymmetric, inertial, dynamics, rigid body, exo-atmospheric, free body. Includes bibliographical references. (p.150-154)
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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.
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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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Wu, Meng-Chou. „Nonlinearity parameters of polymers“. W&M ScholarWorks, 1989. https://scholarworks.wm.edu/etd/1539623784.
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Three types of acoustic nonlinearity parameters for solids are discussed. The results of measurements of these parameters for three polymers--polymethyl methacrylate, Polystyrene, and polysulfone--are presented.;The author has developed a new technique, using piezoelectric transducers directly bonded to the specimens, which allows the measurements of fundamental and second harmonics generated in the solids, and thereby the determination of nonlinearity parameter {dollar}\beta\sb3{dollar}, which is the ratio of a linear combination of second- and third-order elastic coefficients to the second-order elastic coefficient.;The second nonlinearity parameter, B/A can be determined from the temperature and pressure derivatives of the sound velocity. We derive its exact relationship for the case of solids. The results from the two techniques are shown to be consistent.;The pressure derivative of the sound velocity is also related to the Gruneisen parameter, which can be used to describe the anharmonicity of interactions in polymer molecules, especially of interchain vibrations. The interchain specific heat for these polymers is then calculated from the Gruneisen parameters; and the characterization of polymers by using these thermoacoustic parameters is discussed.
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Siddiqui, Asher. „Capturing JUnit Behavior into Static Programs : Static Testing Framework“. Thesis, Linnaeus University, School of Computer Science, Physics and Mathematics, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-5510.
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In this research paper, it evaluates the benefits achievable from static testing framework by analyzing and transforming the JUnit3.8 source code and static execution of transformed code. Static structure enables us to analyze the code statically during creation and execution of test cases. The concept of research is by now well established in static analysis and testing development. The research approach is also increasingly affecting the static testing process and such research oriented work has proved particularly valuable for those of us who want to understand the reflective behavior of JUnit3.8 Framework.
JUnit3.8 Framework uses Java Reflection API to invoke core functionality (test cases creation and execution) dynamically. However, Java Reflection API allows developers to access and modify structure and behavior of a program. Reflection provides flexible solution for creating test cases and controlling the execution of test cases. Java reflection helps to encapsulate test cases in a single object representing the test suite. It also helps to associate each test method with a test object. Where reflection is a powerful tool to perform potential operations, on the other hand, it limits static analysis. Static analysis tools often cannot work effectively with reflection.
In order to avoid the reflection, Static Testing Framework provides a static platform to analyze the JUnit3.8 source code and transform it into non-reflective version that emulates the dynamic behavior of JUnit3.8. The transformed source code has possible leverage to replace reflection with static code and does same things in an execution environment of Static Testing Framework that reflection does in JUnit3.8. More besides, the transformed code also enables execution environment of Static Testing Framework to run test methods statically. In order to measure the degree of efficiency, the implemented tool is evaluated. The evaluation of Static Testing Framework draws results for different Java projects and these statistical data is compared with JUnit3.8 results to measure the effectiveness of Static Testing Framework. As a result of evaluation, STF can be used for static creation and execution of test cases up to JUnit3.8 where test cases are not creating within a test class and where real definition of constructors is not required. These problems can be dealt as future work by introducing a middle layer to execute test fixtures for each test method and by generating test classes as per real definition of constructors.
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Zaritsky, Dennis, und Helene Courtois. „A dynamics-free lower bound on the mass of our Galaxy“. OXFORD UNIV PRESS, 2017. http://hdl.handle.net/10150/623207.
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We use a sample of Milky Way (MW) analogues for which we have stellar and disc gas mass measurements, published measurements of halo gas masses of the MW and of similar galaxies, and the well-established value of the cosmological baryon fraction to place a lower bound on the mass of the Galaxy of 7.7 x 10(11) M-circle dot and estimate that the mass is likely to be >= 1.2 x 10(12) M-circle dot. Although most dynamical analyses yield measurements consistent with these results, several recent studies have advocated for a total mass well below 10(12) M-circle dot. We reject such low-mass estimates because they imply a Galactic baryon matter fraction significantly above the universal value. Convergence between dynamical mass estimates and those based on the baryonic mass is an important milestone in our understanding of galaxies.
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姜瑞娟 und Ruijuan Jiang. „Identification of dynamic load and vehicle parameters based on bridge dynamic responses“. Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B31244270.
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Simms, Christine. „Process optimisation using design experiments and some of the principles of Taguchi : resolving multi-criteria conflicts within parameter design in static and dynamic processes“. Thesis, University of Ulster, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247675.
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Hömberg, Martin [Verfasser], Marcus [Akademischer Betreuer] Müller, Annette [Akademischer Betreuer] Zippelius und 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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Reinert, Susann. „Microbial dynamics in a glycolate fed biogas reactor influenced by abiotic parameters“. Doctoral thesis, Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-172626.
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Much research was performed in order to find alternative energy sources. In the new concept presented in this thesis, methane was produced by a microbial consortium which is fed only by glycolate excreted by photosynthetic algae. It was unknown how the biogas production and the process stability are influenced by certain parameter shifts in glycolate feed, pH of the feed, oxygen
input and temperature. Therefore, different parameter changes were applied to the reactor system. Gas formation and composition, pH, FosTac and organic acid content in the media were analyzed. Additionally, the community composition induced by the changes of the process parameters was analyzed. Therefore, the single cell level using flow cytometry and the genetic level using T-RFLP were observed. The R based tool flowCyBar was applied to follow community dynamics and to find key players in the process. Abiotic and biotic
parameters were used for correlation analysis (Spearman´s Rho) to determine specific functions of sub-communities and the T-RFs found in the whole community.
The cultivation at room temperature indicated that the biogas yield was 30 % lower in comparison to the cultivation at 37°C. The community seemed to be able to sustain pulsating oxygen input in case glycolate as substrate is available. Additionally, the system was able to recover after the oxygen application of one day. A linear correlation between the feed glycolate and the biogas production was observed (R^2 = 0.97). High biogas yields were obtained
(up to 90 %) indicating that glycolate is a suitable substrate. The efficiency of the process was high with 41 ± 3 % methane in the biogas under defined conditions. It could be observed that biogas can be produced on glycolate as mono-substrate by a complex microbial community while it remained complex over the complete study (505 days cultivation) although glycolate was used as sole carbon source. Key sub-communities (e.g. cluster 1 and 3) and T-RFs (e.g. T-RF representing Planctomycetaceae or 67 bp) were defined and indicated the status of the bioreactor. The community was able to sustain certain parameter shifts, like changes in the pH of the feed (from 3 to 7), while others led to a complete crash of the system, like high glycolate feeds (3.6 g d^-1 L^-1). All in all, the stability of the process seemed to be susceptible on external influences.
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Alradaan, Ali. „DYNAMICS OF WASH WATER PARAMETERS IN THE SANITIZATION OF FRESHLY-CUT PRODUCE“. Cleveland State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=csu1526384084438372.
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Tang, Tsing-Young Dora. „Structural parameters and dynamics of lyotropic liquid crystalline phases in hydrated monolinolein“. Thesis, Imperial College London, 2010. http://hdl.handle.net/10044/1/5880.
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To date, the stability of inverse bicontinuous cubic phases and the mechanism of lamellar to cubic transitions are poorly understood due to limited experimental resolution and reproducibility. Systematic experimental data is imperative for reasonable testing and verification of established theoretical models in this area. This thesis focuses on two aspects of lyotropic phase behaviour; the equilibrium behaviour of lyotropic liquid crystalline phases and the transitions between the equilibrium states. When monolinolein (ML) is mixed with water it forms a variety of inverse lyotropic phases, for example the lamellar, inverse bicontinuous phases (QII G and QII D) and the inverse hexagonal phase (HII) which makes this lipid an ideal candidate for study of these phases. The monolinolein equilibrium phase behaviour has been characterised as a function of pressure, temperature and hydration using SAXS (small angle X-ray scattering) and the data used to verify the existence of the pivotal surface in the QII G phase. Knowing the location of the pivotal surface allows one to calculate the total energy of these structures. The second part of this thesis discusses the kinetics of the lamellar to QII G transition in monolinolein under limited hydration conditions using the pressure jump time resolved X-ray diffraction technique. Lamellar to inverse bicontinuous cubic phase transitions are relevant to fundamental cellular processes such as membrane fusion and fission due to structural similarities of the mechanisms. The sequence of structural changes observed from kinetic experiments are discussed in relation to the Stalk Mechanism and the data analysed using a quantitative model.
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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.
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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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Arain, Muhammad Altaf. „Spatial aggregation of vegetation parameters in a coupled land surface-atmosphere model“. Thesis, The University of Arizona, 1994. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_etd_hy0049_m_sip1_w.pdf&type=application/pdf.
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