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1
Cureton, Matthew Alan Chen Yi. "Continuum." Diss., UMK access, 2007.
Знайти повний текст джерелаАнотація:
Thesis (M.M.)--Conservatory of Music. University of Missouri--Kansas City, 2007."A single movement composition for orchestra"--ℓ ii. "A thesis in music composition." Typescript. Advisor: Chen Yi. Vita. Description based on contents viewed Nov. 12, 2007; title from "catalog record" of the print edition. Online version of the print edition.
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Rosenau, Luciana dos Santos. "Continuum." reponame:Repositório Institucional da UFSC, 2017. https://repositorio.ufsc.br/xmlui/handle/123456789/180695.
Повний текст джерелаАнотація:
Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências da Educação, Programa de Pós-Graduação em Educação, Florianópolis, 2017.Made available in DSpace on 2017-11-07T03:23:12Z (GMT). No. of bitstreams: 1 348841.pdf: 25928271 bytes, checksum: ecf93883b64626e9052340f399dcf5ca (MD5) Previous issue date: 2017
A evolução das Tecnologias de Comunicação Digital provoca transformações profundas na sociedade, alterando a noção de tempo e espaço de modo singular nas questões educacionais. O tema desta pesquisa é o Design de Interação de Ambientes Virtuais de Ensino-Aprendizagem (AVEA). O objetivo da pesquisa foi analisar a concepção de um modelo de Design de Interação de um Ambiente Virtual de Ensino-Aprendizagem para uma comunicação efetiva no processo de mediação pedagógica. Este estudo propõe um modelo teórico-metodológico de Design de Interação para construção de um Ambiente Virtual de Ensino-Aprendizagem tendo como foco o processo de comunicação neste ambiente. Para embasar teoricamente esta pesquisa, elege-se a intersecção entre Educação, Comunicação e Design com as potencialidades da Tecnologia. O campo de pesquisa para a fase de concepção do protótipo de AVEA teve como foco os projetos de EaD do Instituto Federal do Paraná ? IFPR. A população alvo foram os estudantes que utilizam o AVEA para estudar nos Cursos Técnicos a distância da Rede e-Tec. A metodologia eleita foi a pesquisa exploratória, utilizando o método de análise misto ? Triangulação. O processo da elaboração do Design compreende três fases: concepção, prototipagem e verificação. A concepção foi elaborada em parceria com a equipe multidisciplinar da Diretoria de Tecnologia de Informação e Comunicação e docentes do IFPR. O modelo foi prototipado em duas turmas de estudantes de EaD e verificado por um grupo de especialistas pela técnica Delphi. O resultado desta pesquisa é um modelo de Design de Interação com condições de garantir a mediação comunicacional assegurando a interação no ensino-aprendizagem, de modo concernente para com o contexto e usabilidade da população em foco. Conclui-se que a integração das Tecnologias de Comunicação Digital utilizadas na Educação a Distância com a maior abertura dos espaços de comunicação do AVEA pode promover maior qualidade e potencializar aprendizagens em níveis mais aprofundados.
Abstract : The evolution of Digital Communication Technologies is provoking profound transformations in society, altering the notion of time and space in a unique manner with regard to education issues. The theme of this research is the Interaction Design of Virtual Learning Environments (VLE). The objective of the research was to analyse the conception of an Interaction Design model for a Virtual Learning Environment for effective communication in the process of pedagogical mediation. This study proposes a theoretical and methodological Interaction Design model for building a Virtual Learning Environment, focusing on the process of communication within this environment. The theoretical foundation chosen for this research is the intersection between Education, Communication and Design and the potentialities of Technology. The field of research for the VLE prototype conception phase focused on the distance learning projects of the Paraná Federal Institute (Instituto Federal do Paraná ? IFPR). The target population were students using VLE to study on e-Tec Network (Rede e-Tec) distance learning Technical Courses. The methodology chosen was exploratory research, using the mixed analysis method of Triangulation. The Design preparation process involves three stages: conception, prototyping and verification. The conception stage took place in partnership with the multidisciplinary team of the IFPR Information and Communications Technology Directorate and IFPR teaching staff. The model prototyping stage was performed with two classes of distance learning students. Verification was performed by a group of experts using the Delphi technique. The result of this research is an Interaction Design model capable of guaranteeing communication mediation ensuring interaction in the teaching-learning process in a pertinent manner for the context and with usability for the population in question. The conclusion reached is that integrating Digital Communication Technology used in Distance Learning with greater availability of VLE communication spaces can aggregate more quality and increase the potential for more in-depth learning.
3
Louis, Dana Lynn. "The Continuum." The Ohio State University, 1988. http://rave.ohiolink.edu/etdc/view?acc_num=osu1300215911.
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Irwin, Shana. "Characterizations of Continua of Finite Degree." Thesis, University of North Texas, 2006. https://digital.library.unt.edu/ark:/67531/metadc5367/.
Повний текст джерелаАнотація:
In this thesis, some characterizations of continua of finite degree are given. It turns out that being of finite degree (by formal definition) can be described by saying there exists an equivalent metric in which Hausdorff linear measure of the continuum is finite. I discuss this result in detail.
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Fadden, Lorna Marie. "The inverse continuum." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ61427.pdf.
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Alruwaili, Khalid Mohammed M. "Continuum and combined continuum-discontinuum analysis of wellbore mechanics and stimulation response." Thesis, Heriot-Watt University, 2016. http://hdl.handle.net/10399/3195.
Повний текст джерелаАнотація:
Wellbore drilling and stimulation activities are interlinked processes within the task of borehole construction. Before drilling a well, the initial stress state in the rock can be defined by three principal stresses, with a typical assumption that these consist of the vertical stress (σv), the maximum horizontal stress (σH) and the minimum horizontal stress (σh). After drilling, the stress state changes around the created borehole. The fundamental engineering problem then is to calculate the stresses around the created borehole and/or at the borehole’s wall. Numerous analytical and numerical models exist to estimate the stresses around a circular hole, but these models cannot explain the observed phenomena either in the field or the lab. Attention here is focused on models that are commonly used to predict the stress state around a circular opening. These models do not account for the sequence of the physical processes, leading to an inadequate stress state estimation. This research investigates the 2D classical analytical method, along with a comparison of that approach against numerical methods. This investigation reveals that the models are not equivalent. This is not because of mathematical issues, but is due to the fact that the mechanical systems expressed by these models are not equivalent. The drilling model captures the physics of the real process which makes it possible to explain some phenomena observed in field and laboratory tests. The drilling model approach is applied for several sedimentary rock examples. The combined continuum-discontinuum method reveals its capability in calculating rock failure and deformation that is comparable to some published laboratory drilling tests. Also, the simulation results shed light into the complex fracture growth regime around the wellbore. Drilling and Hydraulic fracture simulation is carried out for Berea sandstone using both the continuum and the combined continuum-discontinuum methods. The results are in good agreement which identifies a practical engineering method for larger models. The fracturing initiates in Mode II (shear) near the circumference of the wellbore aligned with the maximum stress. At later stages, Mode I (tensile) fractures also develop and propagate the fracture parallel to the maximum horizontal stress. This fracturing mechanism continues for as long as the pressure is applied.
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Houdebert, Pierre. "Continuum Random Cluster Model." Thesis, Lille 1, 2017. http://www.theses.fr/2017LIL10042/document.
Повний текст джерелаАнотація:
Cette thèse s'intéresse au Continuum Random Cluster Model (CRCM), modèle gibbsien de boules aléatoires où la densité dépend du nombre de composantes connexes de la structure. Ce modèle est une version continue du Random Cluster Model introduit pour unifier l'étude des modèles d'Ising et de Potts. Le CRCM fut introduit pour sa relation avec le modèle de Widom-Rowlinson, fournissant une nouvelle preuve de la transition de phase pour ce modèle. Dans cette thèse nous étudions dans un premier temps l'existence du CRCM en volume infinie. Dans le cas extrême des rayons non-intégrables, nous démontrons un résultat de non-unicité du CRCM en petite activité. Nous conjecturons de plus que l'unicité serait obtenue en grande activité. Une version faible de cette conjecture est démontré en dimension 1. Dans un second temps nous étudions la percolation du CRCM, qui s'intéresse aux propriétés de connectivité et en particulier à l'existence d'une composante connexe infinie. La percolation est d'autant plus cohérente pour le CRCM dont l'interaction dépend directement de la connectivité de la structure. Nous montrons dans cette thèse l'absence de percolation en petite activité et la percolation en grande activité. Ce résultat permet de généraliser la transition de phase du modèle de Widom-Rowlinson à des rayons non bornésThis thesis focuses on the Continuum Random Cluster Model (CRCM), defined as a Gibbs model of random balls where the density depends on the number of cluster in the structure. This model is a continuum version of the Random Cluster Model introduced to unify the study of the Ising and Potts model. The CRCM was introduced for its links with the Widom-Rowlinson model, which led to a new proof of the phase transition for this model. In this thesis we first study the existence of the model in the infinite volume regime. In the extreme setting of non integrable radii, we prove for small activities the non-uniqueness of a CRCM. We conjecture that the uniqueness would be revovered for large activities. A weak version of the conjecture is proved.We alson study the percolation of the CRCM, which is the existence of at least one unbounded connected component. Percolation is more relevant for the CRCM since the interaction depends on the connectivity of the structure. We prove the absence of percolation for small activities and percolation for large activities. This results leads to the phase transition of the Widom-Rowlinson model with unbounded radii
8
Kellermann, David Conrad Mechanical & Manufacturing Engineering Faculty of Engineering UNSW. "Strongly orthotropic continuum mechanics." Publisher:University of New South Wales. Mechanical & Manufacturing Engineering, 2008. http://handle.unsw.edu.au/1959.4/41454.
Повний текст джерелаАнотація:
The principal contribution of this dissertation is a theory of Strongly Orthotropic Continuum Mechanics that is derived entirely from an assertion of geometric strain indeterminacy. Implementable into the finite element method, it can resolve widespread kinematic misrepresentations and offer unique and purportedly exact strain-induced energies by removing the assumptions of strain tensor symmetry. This continuum theory births the proposal of a new class of physical tensors described as the Intrinsic Field Tensors capable of generalising the response of most classical mechanical metrics, a number of specialised formulations and the solutions shown to be kinematically intermediate. A series of numerical examples demonstrate Euclidean objectivity, material frame-indifference, patch test satisfaction, and agreement between the subsequent Material Principal Co-rotation and P??I??C decomposition methods that produce the intermediary stress/strain fields. The encompassing theory has wide applicability owing to its fundamental divergence from conventional mechanics, it offers non-trivial outcomes when applied to even very simple problems and its use of not the Eulerian, Lagrangian but the Intrinsic Frame generates previously unreported results in strongly orthotropic continua.
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Wauchope, Liz, and n/a. "An affirmation action continuum." University of Canberra. Administrative Studies, 1987. http://erl.canberra.edu.au./public/adt-AUC20061109.171449.
Повний текст джерелаАнотація:
The development of affirmative action strategies designed to achieve equal employment opportunity has been studied along six dimensions of functioning
within four separate organisations. Three of these organisations were
participants in the Federal Government's Affirmative Action Pilot Program in
1984/5, and one was not.
It has been shown that change occurred in a continuous developmental
sequence, here called an "Affirmative Action Continuum", within each of
these six dimensions over the period of study, with each organisation
following a similar sequence of movement. Exceptions occurred where an
organisation made no movement at all, or where one or more of the
sequential processes was omitted or displaced, in a dimension. The
reasons for some of these exceptions, and some of their consequences for
later action, have been explored.
It has been shown that simultaneous activity occurred across several,
dimensions, so that no organisation acted upon only one dimension in
isolation from all others. There was some chronological sequencing between
dimensions.
The indicators of movement along the Affirmative Action Continuum within
each dimension were used to describe the change process in each
organisation. These indicators proved to be useful both in this regard,
and in placing each organisation an the Affirmative Action Continuum in
each dimension at two different points in time. In this way, the
indicators' usefulness was shown to generalise to four very different
institutions, thus suggesting applicability beyond the bounds of this
particular study.
It is intended that the results of this dissertation, and in particular the
model of the Affirmative Action Continuum and the indicators described in
Chapter Two, be used by Equal Employment Opportunity practitioners to
facilitate their decision making about sequencing of activities designed to
achieve equal employment oppportunity.
10
Wu, Huan. "Atomistic-to-continuum coupling." Thesis, University of Warwick, 2017. http://wrap.warwick.ac.uk/101783/.
Повний текст джерелаАнотація:
The present thesis is on error analysis of atomistic-to-continuum (A/C) coupling models for crystal defects, which is a class of multi-scale coupling models that combine atomistic interactions around the defect cores and continuum elasticity models at far-fields This thesis consists of two parts. The first part presents a sharp error analysis of an A/C model in 2D with high-order finite element methods, whereas in the past the analysis for employing FEM has been restricted to first-order. The second part discusses a new A/C coupling scheme employing a boundary element method to improve the description of the far-field. In the first part we formulate a \patch test consistent" atomistic-to-continuum coupling (a/c) scheme that employs a second-order (potentially higher-order) finite element method in the material bulk. We prove a sharp error estimate in the energy-norm, which demonstrates that this scheme is (quasi-)optimal amongst energy-based sharp-interface a/c schemes that employ the Cauchy{Born continuum model. Our analysis also shows that employing a continuum discretization with order greater than two does not yield qualitative improvements to the rate of convergence. In the second part we formulate a new A/C coupling scheme that employs a boundary element method to obtain an improved far- field boundary condition. We establish sharp error bounds in a 2D model problem for a point defect embedded in a homogeneous crystal. The error analysis shows that it is possible to entirely bypass the FEM region while maintaining an optimal convergence rate. The thesis is accompanied by an introduction to atomistic-to-continuum coupling and literature review on various coupling methods and the general framework for error analysis.
11
Misse, Bruno Henrique Labriola. "Continuum : Matemática, Filosofia e Computação /." Rio Claro, 2019. http://hdl.handle.net/11449/191418.
Повний текст джерелаАнотація:
Orientador: Maria Aparecida Viggiani BicudoResumo: A continuidade é um tema que sempre trouxe desafios aos filósofos e matemáticos, desde a Grécia antiga com os paradoxos sobre o movimento, que persistem até os dias atuais, quando nos encontramos discutindo a continuidade da consciência e do tempo. Com o advento da tecnologia digital uma perspectiva se abre nessa discussão, pois modelos matemáticos contínuos estão sendo aplicados a problemas numéricos computacionais, que são caracteristicamente discretos. Essa possível discretização do contínuo mostra-se de modo claro, levando-nos a investigar a presença do contínuo ao se produzir Matemática junto ao computador. Investigaremos esse assunto realizando um movimento característico do pensar filosófico, tomando o tema como uma lectio, entendida como momento de discussão sobre textos numa dimensão argumentativa filosófica sobre nossa interrogação de pesquisa, ou seja, nossa quaestio. Nossa compreensão dos textos é exposta de maneira articulada e dividida em três seções, que versam sobre os estudos realizados no âmbito das Ciências Matemática, Filosofia e Computação. Finalizaremos trazendo uma meta-compreensão dos estudos realizados, tomando como centro articulador da reflexão a interrogação formulada. Nosso objetivo com esse exercício filosófico é compreender o fenômeno “contínuo-discreto” na região de inquérito das Ciências Ocidentais e sua presença na computação
Abstract: Continuity has been a challenging topic to philosophers and mathematicians, since the ancient Greece, with paradoxes of movement, until present days when continuity of consciousness and of time are discussed. With the advent of digital technology another perspective has brought into the discussion, because continuous mathematical models are being applied in numerical computational problems, which are characteristically discrete. This possibility of continuos’ discretization is drawing our attention. Therefore, this research aims to understand the presentification of continuous when we are producing Mathematics with computers. We will investigate this subject via a philosophical approach. This thesis is constituted as a lectio, understood as a moment of discussion about texts in a philosophical argumentative dimension about our research question, that is, our quaestio. Our understanding of the texts is articulated and divided into three sections, which deal with the studies carried out in Mathematics, Philosophy and Computer Science. Our goal with this philosophical exercise is to explore the "continuous-discrete" phenomenon under Western Sciences influence and its presence in computation.
Doutor
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Rajamani, Vignesh. "Heat transfer in continuum and non-continuum plasma flows in material processing applications." Cincinnati, Ohio : University of Cincinnati, 2005. http://www.ohiolink.edu/etd/view.cgi?acc%5Fnum=ucin1130076192.
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RAJAMANI, VIGNESH. "HEAT TRANSFER IN CONTINUUM AND NON-CONTINUUM PLASMA FLOWS IN MATERIALS PROCESSING APPLICATIONS." University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1130076192.
Повний текст джерела
14
Schiltges, Gilbert. "Continuum mechanical investigations on microstructures /." [S.l.] : [s.n.], 1999. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=13265.
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Menzel, Andreas. "Frontiers in inelastic continuum mechanics." Kaiserslautern Techn. Univ., Lehrstuhl für Techn. Mechanik, 2007. http://d-nb.info/99794563X/34.
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16
Xin, W. (Weidong). "Continuum electrostatics of biomolecular systems." Doctoral thesis, University of Oulu, 2008. http://urn.fi/urn:isbn:9789514287602.
Повний текст джерелаАнотація:
Abstract
Electrostatic interactions are very important in biomolecular systems. Electrostatic forces have received a great deal of attention due to their long-range nature and the trade-off between desolvation and interaction effects. It remains a challenging task to study and to predict the effects of electrostatic interactions in biomolecular systems. Computer simulation techniques that account for such interactions are an important tool for the study of biomolecular electrostatics.
This study is largely concerned with the role of electrostatic interactions in biomolecular systems and with developing novel models to estimate the strength of such interactions.
First, a novel formulation based upon continuum electrostatics to compute the electrostatic potential in and around two biomolecules in a solvent with ionic strength is presented. Many, if not all, current methods rely on the (non)linear Poisson-Boltzmann equation to include ionic strength. The present formulation, however, describes ionic strength through the inclusion of explicit ions, which considerably extends its applicability and validity range. The method relies on the boundary element method (BEM) and results in two very similar coupled integral equations valid on the dielectric boundaries of two molecules, respectively. This method can be employed to estimate the total electrostatic energy of two protein molecules at a given distance and orientation in an electrolyte solution with zero to moderately high ionic strength.
Secondly, to be able to study interactions between biomolecules and membranes, an alternative model partly based upon the analytical continuum electrostatics (ACE) method has been also formulated. It is desirable to develop a method for calculating the total solvation free energy that includes both electrostatic and non-polar energies. The difference between this model and other continuum methods is that instead of determining the electrostatic potential, the total electrostatic energy of the system is calculated by integrating the energy density of the electrostatic field. This novel approach is employed for the calculation of the total solvation free energy of a system consisting of two solutes, one of which could be an infinite slab representing a membrane surface.
17
Wiker, Niclas. "Optimization in Continuum Flow Problems." Doctoral thesis, Linköpings universitet, Mekanik, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-14857.
Повний текст джерелаАнотація:
The work presented in this dissertation was carried out at the Division ofMechanics, Department of Management and Engineering at Link¨oping University,between 2003 and 2008. It was supervised by Prof. Anders Klarbring,head of the division, and financially supported by the National GraduateSchool of Scientific Computing (NGSSC) and the Swedish Research Council(VR). There are many people to whom I would like to express my gratitude: firstand foremost I would like to thank my supervisor Prof. Anders Klarbring forhis help, support and endless patience during our discussions, and for alwayshaving time to read and comment on the numerous drafts that eventually ledto the research manuscripts presented in this thesis. I would also like to thankmy co–supervisor Dr. Thomas Borrvall for all his help regarding numericalissues, especially with the implementation of the models. Moreover, I wouldlike to thank present and former colleagues for their inspiration and assistanceduring my time as a graduate student at the division. Last but not least, I am very grateful for having a family that has alwaysbeen there to support me, and for all my friends who enrich my life outsidethe office walls in more ways then I can say.
18
Griffiths, Robert P. "Continuum modeling of interface failure." Thesis, Monterey, Calif. : Naval Postgraduate School, 2007. http://bosun.nps.edu/uhtbin/hyperion-image.exe/07Dec%5FGriffiths.pdf.
Повний текст джерелаАнотація:
Thesis (M.S. in Mechanical Engineering)--Naval Postgraduate School, December 2007.Thesis Advisor(s): Kwon, Young W. "December 2007." Description based on title screen as viewed on January 18, 2008 Includes bibliographical references (p. 39-40). Also available in print.
19
Csencsits, Matthew A. "Operational strategies for continuum manipulators." Connect to this title online, 2007. http://etd.lib.clemson.edu/documents/1202500813/.
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DeGiuli, Eric. "Continuum limits of granular systems." Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/44393.
Повний текст джерелаАнотація:
Despite a century of study, the macroscopic behaviour of quasistatic granular materials remains poorly understood. In particular, we lack a fundamental system of continuum equations, comparable to the Navier-Stokes equations for a Newtonian fluid. In this thesis, we derive continuum models for two-dimensional granular materials directly from the grain scale, using tools of discrete calculus, which we develop.
To make this objective precise, we pose the canonical isostatic problem: a marginally stable granular material in the plane has 4 components of the stress tensor σ, but only 3 continuum equations in Newton’s laws ∇ ‧σ = 0 and σ = σT. At isostaticity, there is a missing stress-geometry equation, arising from Newton’s laws at the grain scale, which is not present in their conventional continuum form.
We first show that a discrete potential ψ can be defined such that the stress tensor is written as σ = ∇ × ∇ × ψ, where the derivatives are given an exact meaning at the grain scale, and converge to their continuum counterpart in an appropriate limit. The introduction of ψ allows us to understand how force and torque balance couple neighbouring grains, and thus to understand where the stress-geometry equation is hidden.
Using this formulation, we derive the missing stress-geometry equation ∆(F^ : ∇∇ψ) = 0, introducing a fabric tensor F^ which characterizes the geometry. We show that the equation imposes granularity in a literal sense, and that on a homo- geneous fabric, the equation reduces to a particular form of anisotropic elasticity.
We then discuss the deformation of rigid granular materials, and derive the mean-field phase diagram for quasistatic flow. We find that isostatic states are fluid states, existing between solid and gaseous phases. The appearance of iso- staticity is linked to the saturation of steric exclusion and Coulomb inequalities.
Finally, we present a model for the fluctuations of contact forces using tools of statistical mechanics. We find that force chains, the filamentary networks of con- tact forces ubiquitously observed in experiments, arise from an entropic instability which favours localization of contact forces.
21
Jungen, Mathias. "Continuum models of columnar jointing." Thesis, University of Oxford, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.418526.
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Titchener, J. B. "Continuum models for dislocation distributions." Thesis, University of Oxford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382704.
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23
Dixon, Matthew Francis. "Geometric integrators for continuum dynamics." Thesis, Imperial College London, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.502473.
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Rinaldi, Carlos (Carlos M. Rinaldi-Ramos) 1975. "Continuum modeling of polarizable systems." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/8501.
Повний текст джерелаАнотація:
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2002.Vita.
Includes bibliographical references.
The basic equations embodying macroscopic conservation and balance statements applicable to polarizable media are derived phenomenologically. These general balance statements are then applied to the particular case of ferrofluids, thereby obtaining the governing equations for isothermal incompressible ferrofluid flows. The governing equations thus obtained are subsequently used to extend previous models of plane-Poiseuille and Couette flow of ferrofluids in alternating and rotating uniform magnetic fields, including the effects of couple stresses. We obtain analytical expressions for the translational and spin velocity profiles, vorticity profiles, volumetric flow rate, and the shear force on a moving duct surface, comparing the effects of various boundary conditions for the spin velocity at the duct walls. Simple representative shearing experiments are proposed to differentiate between wall boundary conditions and to determine key rheological parameters of the fluid. Extending the plane-flow analysis to the analogous cylindrical geometry, a regular perturbation scheme is used to solve the coupled ferrohydrodynamic problem of spin-up flow of ferrofluid in a uniform rotating magnetic field. Our approach properly accounts for the spin-magnetization coupling term in the magnetization equation, neglected in prior analyses. The features and contributions of terms up to third order in the expansion parameter are obtained and discussed. The predicted flow profiles possess the major characteristics of the observed flow phenomena, as compared to results in the literature. The torque required to restrain the cylindrical container wall is evaluated and the limits of applicability of the analysis are explored.
(cont.) Finally, the thermodynamics of polarizable systems in external force fields is examined by considering "exact" and "coarse-grained" descriptions of mass-, charge- and magnetically-polarized continua in external gravitational, electric, and magnetic fields. Starting from an exact micromechanical model of the energetics for a change of state of said system, we derive corresponding coarse-grained expressions where the internal distribution of the relevant scalar measure is represented by a series of polarization moments, arbitrarily truncated at a given order. As such, the analysis introduces a new canonical thermodynamic state variable, the polarization T3 (of mass, charge or "magnetic monopoles"). The irreversible thermodynamics of ferrofluids is subsequently considered. Simple experimental systems are introduced and discussed.
by Carlos Rinaldi.
Ph.D.
25
Wang, Xiaolin. "Continuum modelling of cellular solids." Thesis, University of Cambridge, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.624856.
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Al-Taie, Ali Hussein Shuaa. "Continuum models for fungal growth." Thesis, University of Dundee, 2011. https://discovery.dundee.ac.uk/en/studentTheses/9b2c14ff-c012-4541-a6ea-3ab0fea38e50.
Повний текст джерелаАнотація:
Fungi generally exist as unicellular organisms (yeasts) or in a vegetative state in which a mycelium, i.e. an interconnected network of tubes (hyphae) is formed. The mycelium can operate over a very large range of scales (each hypha is only a few microns in diameter, yet mycelia can be kilometres across). Fungi are of fundamental importance to many natural processes: certain species have major roles in decomposition and nutrient cycling in the soil; some form vital links with plant roots allowing nutrient transfer. Other species are essential to industrial processes: citric acid production for use in soft drinks; brewing and baking; treatment of industrial effluent and ground toxins. Unfortunately, certain species can cause devastating damage to crops, serious disease in humans or can damage building materials. In this thesis we constructed new models for the development of fungal mycelia. At this scale, partial differential equations representing the interaction of biomass with the underlying substrate is the appropriate choice. Models are essentially based on those derived by Davidson and co workers (see e.g. Boswell et al.(2007)). These models are of a complex mathematical structure, comprising both parabolic and hyperbolic parts. Thus, their analytic and numerical properties are nontrivial. The objectives of this thesis are to: (i) obtain a solid understanding of the physiology of growth and function and the varying mathematical techniques used in model construction. (ii) revisit existing models to reinterpret the various model components in a simple form. (iii) construct models to compare the growth dynamics of different phenotype for new species to see if these "scale " appropriately.
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Ignace, Richard. "Continuum Polarization in Circumstellar Media." Digital Commons @ East Tennessee State University, 2014. https://dc.etsu.edu/etsu-works/6280.
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Gouws, Cliff. "Magazine Hill : a weathered continuum." Diss., University of Pretoria, 2011. http://hdl.handle.net/2263/29983.
Повний текст джерелаАнотація:
NDLTD Innovative ETD Award 2012. This dissertation is rooted within a process of unification, a personal struggle to understand the fragile relationship that exists between architecture and time. The project focuses on architecture’s potential to adapt according to the passage of time, through the process of aging and weathering. This study is founded in the aim to re-establish a connection between the continuum of time and architecture. The project places contemporary commemorative architecture under the limelight, criticising the static notion of heritage commemoration through the typologies of museums and memorials. These typologies often evolve into static monuments, where the relevance to contemporary society can be questioned. The architectural response of this dissertation is thus focused on commemoration through everyday use. The proposed historical site (Magazine Hill) forms a comprehensive construct of different layers of time and influence. This mysterious, abandoned and isolated site consists of two ammunition magazines, five bomb shelters and ammunition factories, all structures that represent an era of unrest in South Africa. In 1945 a mysterious explosion of the Central Magazine scarred the face of Magazine Hill, leading the activities on the site to an early death, trapping architecture in time and abandonment. The proposed programme forms part of the conceptual premise of mediation, unifying different opposites inherent in both Magazine Hill and the South African context. A brass foundry is proposed to recycle the spent ammunition shells of the South African National Defence Force (SANDF), thereby introducing brass artists as a public interface to Magazine Hill. Where ammunition was once produced, ammunition is now reduced. This programme could form mediation between the public and the military; exposing different layers of the past by reinstating a connection between architecture and time. View Clifford Gouw's video on YouTube. Copyright 2011, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. Please cite as follows: Gouws, C 2011, Magazine Hill : a weathered continuum, MArch(Prof) dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-11302011-195515 / > C12/4/86/gmDissertation (MArch(Prof))--University of Pretoria, 2011.
Architecture
unrestricted
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Bai, Wei. "Percolation: Discrete and Continuum Models." Kent State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=kent1406757985.
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Popovic, Marko. "Continuum mechanics of developing epithelia:." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-227283.
Повний текст джерелаАнотація:
Developing tissues are out-of-equilibrium systems that grow and reshape to form organs in adult animals. They are typically composed of a large number of cells. The constitutive cells of a tissue perform different roles in tissue development and contribute to the overall tissue shape changes.
In this thesis, we construct a hydrodynamic theory of developing epithelial tissues. We use it to investigate the developing wing of the fruit fly Drosophila melanogaster. This theory relates the coarse-grained cell scale properties to the large-scale tissue flows. We explicitly account for the active cellular processes in the tissue that drive tissue flows. In our description of the tissue, we also include the memory effects that are necessary to account for the experimental observations. These memory effects have a significant influence on the tissue rheology.
Using this hydrodynamic theory we analyze shear flow in a developing fruit fly wing tissue. We find that the active cellular processes contribute to overall tissue flows and that memory effects are present in the wing tissue. We investigate consequences of these findings on the rheology of tissue shear flow. We find that the memory effects give rise to an inertial response that leads to oscillations in the tissue but it does not stem from the wing mass. Finally, we describe how the tissue rheology is affected by different boundary conditions.
We then investigate the area changes during the pupal wing development and we construct a mechanosensitive model for the cell extrusion rate in the pupal wing. Analysis of cell extrusions in the context of this model also allows us to extract information about the cell division properties.
Boundary connections between the wing tissue and surrounding cuticle are crucial for the proper development of the pupal wing. A dumpy mutant wing is strongly misshaped during the pupal wing morphogenesis. We use a simple model for the wing to show that the dumpy mutant wing can be described as a wild type wing with compromised boundary conditions.
Finally, we analyze cell properties and tissue flows in a developing wing disc epithelium. Motivated by the observation of radially oriented active T1 transitions in the wing disc epithelium, we use the hydrodynamic theory to investigate the influence of such T1 transitions on stresses in the tissue. We show that sufficiently strong radially oriented active T1 transitions can contribute to the control of the tissue size.
Results obtained in this thesis extend our understanding of the fly wing tissue rheology and the role of internal and external forces in the proper shaping of the wing epithelium. The hydrodynamic theory we use to describe the fly wing development provides a set of phenomenological parameters that characterize the tissue mechanics and can be experimentally measured. Therefore, we expect that future research will include and extend the hydrodynamic theory presented in this thesis.
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Smith, Matthew Ross. "Hybrid methods in near continuum flows /." [St. Lucia, Qld], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18282.pdf.
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Abdi, Tadesse. "Towards material modelling within continuum-atomistics." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=979984173.
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Karlson, Kyle N. "Multiscale continuum modeling of protein dynamics." Thesis, Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/43683.
Повний текст джерелаАнотація:
Two multiscale continuum models for simulating protein dynamics are developed which allow for resolution of protein peptide planes in a beam-like finite element. A curvature and strain based finite element formulation is utilized. This formulation is advantageous in simulating proteins since amino acid chains may be described by a single element, even when the protein segment considered exhibits large curvature and twist such as the alpha-helical shapes prominent in many proteins. Specifically, concurrent and hierarchical multiscale models are developed for the curvature and strain based beam formulation. The hierarchical multiscale continuum model utilizes a novel shooting method to calculate the deformed configuration of the protein. An optimization algorithm determines the requisite stiffness parameters by varying the beam stiffness used in the shooting method until deformed configurations of test cases correspond to those produced by the LAMMPS molecular dynamics software. Additionally, a concurrent multiscale method is detailed for evaluating protein inter-atomic potential parameters from the curvature and strain degrees of freedom employed in the model. This allows internal forces and moments to be calculated using nonlinear protein potentials. Proof of concept testing and model verification for both models includes comparing the multiscale techniques to all-atom molecular dynamics solutions. Specifically, the models are verified by simulating a polypeptide in a vacuum and comparing the predicted results to those computed using LAMMPS.
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Borrvall, Thomas. "Computational topology optimization in continuum mechanics /." Linköping : Univ, 2002. http://www.bibl.liu.se/liupubl/disp/disp2002/tek744s.pdf.
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Nyman, Ulf. "Continuum mechanics modelling of corrugated board /." Lund : Univ, 2004. http://www.byggmek.lth.se/.
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Done, Christine. "Nonthermal continuum processes in compact objects." Thesis, University of Cambridge, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317768.
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Armstrong, Nicola J. "Continuum modelling of cell-cell adhesion." Thesis, Heriot-Watt University, 2008. http://hdl.handle.net/10399/2167.
Повний текст джерелаАнотація:
Cells adhere to each other through the binding of cell adhesion molecules at the cell surface. This process, known as cell-cell adhesion, is fundamental in many areas of biology, including early embryo development, tissue homeostasis and tumour growth. Here \~e present a new continuum mathematical model of this phenomenon by considering · the movement of cells in response to the adhesive forces generated through binding. We demonstrate that the model predicts aggregative behaviour, characteristic of an adhesive cell population. Further, when extended to two cell populations, the model predicts cell sorting behaviour dependent on the strengths of adhesive bonds between cells. While cell sorting has been demonstrated previously with discrete approaches, we believe that this is the first continuous model to capture this behaviour. In the latter part of this work we apply the model of cell-cell adhesion to somitogenesis and tumour growth. In applying the model to somitogenesis we demonstrate that the model predicts somite formation under particular parameter constraints. We suggest that these parameter constraints may provide a means by which to test competing theories of the mechanisms responsible for somitogenesis. In applying the model to tumour growth and invasion we demonstrate that the model predicts that mutations which alter cells adhesive properties have a significant influence on tumour dynamics. In particular, the model predicts that irregular invasion patterns are the consequence of increased cell-matrix adhesion and an inhomogeneous host environment.
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Wei, Zhiyan. "Studies in discrete and continuum mechanics." Thesis, Harvard University, 2014. http://dissertations.umi.com/gsas.harvard:11582.
Повний текст джерелаАнотація:
We have used a combination of theory and computation to investigate collective aspects of discrete mechanical systems. The analysis involves considerations from geometry, elasticity and hydrodynamics. We have developed continuum theories to describe these systems, in the spirit of compressing information by mathematical abstraction from the discrete description.Engineering and Applied Sciences
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McMillan, E. "Atomistic to continuum models for crystals." Thesis, University of Oxford, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288533.
Повний текст джерелаАнотація:
The theory of nonlinear mass-spring chains has a history stretching back to the now famous numerical simulations of Fermi, Pasta and Ulam. The unexpected results of that experiment have led to many new fields of study. Despite this, the mathematics of the lattice equations have proved sufficiently rich to attract continued attention to the present day. This work is concerned with the motions of an infinite one dimensional lattice with nearest-neighbour interactions governed by a generic potential. The Hamiltonian of such a system may be written $H = \sum_{i=-\infty}^{\infty} \, \Bigl(\frac{1}{2}p_i^2 + V(q_{i+1}-q_i)\Bigr)$, in terms of the momenta $p_i$ and the displacements $q_i$ of the lattice sites. All sites are assumed to be of equal mass. Certain generic conditions are placed on the potential $V$. Of particular interest are the solitary wave solutions which are known to exist upon such lattices. The KdV equation has long been known to emerge in a formal manner from the lattice equations as a continuum limit. More recently, the lattice's localized nonlinear modes have been rigorously approximated by the KdV's well-studied soliton solution, in the lattice's long wavelength regime. To date, however, little is known about how, and to what extent, lattice solitary waves differ from KdV solitons. It is proved in this work that a solution (which we prove to be unique) to a particular linear ordinary differential equation provides a correction to the KdV approximation. This gives, in an explicit way, the lowest order effect of lattice discreteness upon lattice solitary waves. It is also shown how such discreteness effects are propagated along the lattice both in isolation (single soliton case), and in the presence of another soliton correction (the bisoliton case). In the latter case their interaction is studied and the impact of lattice discreteness upon lattice solitary wave interactions is observed. This is possible by virtue of the discovery of an evolution equation for discreteness effects on the lattice. This equation is proved to have appropriate unique solutions and is found to be strikingly similar to corresponding equations known in both the theories of shallow water waves and ion-acoustic waves.
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Sembay, S. F. "Continuum radiation from Active Galactic Nuclei." Thesis, University of Southampton, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377792.
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Olsen, Tyler J. (Tyler John). "Continuum modeling of particle suspension conductivity." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/101480.
Повний текст джерелаАнотація:
Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2015.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 91-94).
A suspension of network-forming, electrically conductive particles imparts electrical conductivity to an otherwise insulating medium. This effect can be used to great effect in many industrial applications. The ability to describe these networks and to predict their physical properties is a key step in designing systems that rely on these properties. In addition, many times these networks are suspended in a flowing fluid, which disrupts existing networks and forms new ones. The extra layer of complexity introduced by flow requires more sophisticated tools to model the effect on the network and its properties. In the first chapter, we derive a model for the full, tensorial effective conductivity of a particle particle network as a function of a local tensor description of the particle network, the "fabric tensor." We validate our model against a large number of computer-generated networks and compare its performance against an analogous existing model in the literature. We show that the model accurately predicts the isotropic magnitude, deviatoric magnitude, and deviatoric direction of a particle network. In the second chapter, we set out to model the effects of flow on a particle network. We propose two frame-indifferent constitutive equations for the evolution of the fabric tensor. We perform conductivity measurements of real flowing carbon black suspensions and fit our models to the results by using the conductivity model derived in chapter 1. We find that our models are able to reproduce out-of-sample experimental results with a high degree of accuracy.
by Tyler J. Olsen.
S.M.
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Murry, Robert Lester. "Continuum electrostatic analysis of DNA bending." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/38837.
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Osborne, Mark Jonathan. "Continuum theory of smectic A elastomers." Thesis, University of Cambridge, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.620653.
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Allardyce, Susan. "A continuum approach to lifestyle entrepreneurship." Thesis, Robert Gordon University, 2015. http://hdl.handle.net/10059/1223.
Повний текст джерелаАнотація:
Recent years have witnessed an increased interest in small independently operated businesses with researchers expressing an interest in the manner in which the independent owner-operator is motivated to enter the market and their subsequent approach to business. Research into these small firms has shown that the owner/operators may create their businesses for a variety of reasons. However an emerging perspective is that not all individuals will actively pursue traditional objectives such as growth and profit maximisation, rather they are increasingly choosing their occupation to suit their ‘style of life’. Lifestyle motivations have thus been recognised in the literature as important stimuli to small business formation. Various research has been undertaken into the lifestyle construct and the impact on the motivations and behaviours of the individual towards the creation and development of smallscale enterprises. This study aims to build on recent work in this area to provide an enhanced understanding of lifestyle theory. This study adopts an interpretivist approach to understand the fundamental meanings attached to lifestyle entrepreneurship in the context of the small business. Bed and Breakfast (B&B) accommodation operations are used as a frame through which to understand the motivations of the individual towards venture creation. This study develops the ideal typifications of Business Orientated Lifestylers, Lifestyle Focused Business Performers and Self Expressive Homemakers to help explain the complex and dynamic range of lifestyle motivations and objectives present, and proposes the model of a continuum to portray these lifestyle business owners as being between low intensity and high intensity lifestyle goals and objectives. It is suggested that the typologies and subsequent lifestyle continuum presented in this study can be used by researchers, policy makers and practitioners to better understand the lifestyle entrepreneur and the environment within which they operate, and further, to support these lifestyle entrepreneurs in the operation of their business.
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Millard, David Edward. "Hypermedia interoperability : navigating the information continuum." Thesis, University of Southampton, 2000. https://eprints.soton.ac.uk/259234/.
Повний текст джерелаАнотація:
Open Hypermedia Systems are designed to allow links to be authored and followed on top of any media format. The link structures are held separately from the documents in a software component called a Link Server. As hypermedia has matured as a research topic attention has turned to standardising the way in which components talk to Link Servers in order to provide interoperability. The Open Hypermedia Systems Working Group took up this challenge and proposed an Open Hypermedia Protocol (OHP). However, the scope of this proposal proved to be too large and the protocol was divided into domain specific parts (Navigational, Spatial and Taxonomic Hypermedia), tackling each domain differently, but consistently. It is questionable whether this step was the correct one, as the domains share many similar features. In this thesis I present a detailed examination of the information spaces that the OHP was attempting to model (from all these considered hypertext domains), which incorporates notions of both behaviour and context. This examination looks at what it means to navigate around the many dimensions of information, across these domains, and reveals a cohesive and continuous structure that I call the Information Continuum. The Fundamental Open Hypermedia Model (FOHM) is presented, which is capable of representing the structures of this continuum in a consistent and meaningful way. FOHM is coupled with an agent infrastructure to produce an implementation that demonstrates the model being used for cross-domain interoperability.
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Curran, Patrick. "Continuum : dispositif de simulation multidimensionnelle unifié." Paris 8, 1991. http://www.theses.fr/1991PA080634.
Повний текст джерелаАнотація:
Recherche-action systémique portant sur la comparaison et l'harmonisation entre les processus cognitifs et relationnels immédiats et leur médiation technologique. La place épicentrique de l'individu dans le dispositif est expliquée puis affirmée autour d'applications interactives basées sur la simulation, en mode hypermédiatique, d'environnements et de scénarios virtuelsA systemic hands on research on the comparison and harmonization of immediate relational and cognitive processes and their technological mediation. Person's epicentric position on the set up is explored and posited around interactive applications based on hypermedia simulation of virtual scenarios and environments
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Thorapalli, Muralidharan Seshagopalan, and Ruihao Zhu. "Continuum Actuator Based Soft Quadruped Robot." Thesis, KTH, Mekatronik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-286348.
Повний текст джерелаАнотація:
Quadruped robots can traverse a multitude of terrains with greater ease when compared to wheeled robots. Traditional rigid quadruped robots possess severe limitations as they lack structural compliance. Most of the existing soft quadruped robots are tethered and are actuated using pneumatics, which is a low grade energy source and lacks viability for long endurance robots. The work in this thesis proposes the development of a continuum actuator driven quadruped robot which can provide compliance while being un-tethered and electro-mechanically driven. In this work, continuum actuators are developed using mostly 3D printed parts. Additionally, the closed loop control of continuum actuators for walking is developed. Linear Quadratic Regulator (LQR) and pole placement based methods for controller synthesis were evaluated and LQR was determined to be better when minimizing the actuator effort and deviation from set-point. These continuum actuators are composed together to form a quadruped. Gait analyses on the quadruped were conducted and legs of the quadruped were able to trace the gaits for walking and galloping.Fyrfotarobotar kan lättare korsa en mängd olika terränger jämfört med hjulrobotar. Traditionella styva fyrfotarobotar har kraftiga begränsningar då de saknar strukturell följsamhet. De flesta befintliga mjuka fyrbenta robotar är kopplade till en eller flera kablar och drivs av pneumatik, vilket är en lågkvalitativ energikälla och lämpar sig inte för robotar med lång uthållighet. Arbetet i denna avhandling föreslår utvecklingen av en continuum ställdonsdriven fyrfotarobot, som ger följsamhet samtidigt som den ¨ar frånkopplad och elektromekaniskt driven. I detta arbete framställs continuum ställdon med mestadels 3D-printade delar. Dessutom utvecklas dessa ställdons slutna kontrolloop för gång. Linjärkvadratisk regulator (LQR) och metoder baserade på polplacering utvärderades för styrsyntes, och det fastställdes att LQR presterade bättre när man minimerar ställdonets ansträngning samt avvikelse från referensvärde. Continuum ställdon sammansattes för att bilda en fyrbent robot. Gånganalyser utfördes på roboten och dess ben kunde följa gång- och galopprörelser.
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Scriba, Christian. "Neurosis - Continuum [ Architecture As Urban Therapy ]." Master's thesis, University of Cape Town, 2016. http://hdl.handle.net/11427/23033.
Повний текст джерелаАнотація:
This dissertation is rooted within the personal struggle to understand the absurdity of spaces which exist within Woodstock, Cape Town. The project draws a psychological connection between the site and its absurdities, implying that spatial absurdity is the effect of problems of the personified "sitemind". By visualizing what are called "neurosis spaces" the expressions of site-mind anxieties, and arranging them into a speculative site, the project creates a space of analogy. A space for which architecture becomes a therapy. Architecture in application thereby embodies therapy, forming an intervention which itself enacts the speculative analogy. The proposal is therefore seated firmly between the real and the imagined. A victim Offender Rehabilitation center mediates the analogy physically creating an architecture that plays on spatial experience and programming to create a place of therapy, a machine of sublimation.
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Iqbal, Muhammad Sohail. "Continuum robot modeling with guaranteed approach." Thesis, Paris Est, 2010. http://www.theses.fr/2010PEST1027.
Повний текст джерелаАнотація:
Contrairement aux robots conventionnels, les robots continuums ne possèdent ni de liaisons discrètes, ni de corps rigides. Leur courbure est continue, similaire à celle des trompes ou des tentacules animales. Le développement de ce type de robots pour les applications médicales soulève plusieurs problèmes : optimisation de la conception, modélisation cinématique, choix des capteurs et commande en temps réel. Les techniques actuelles pour la modélisation des robots continuums ne tiennent pas compte les incertitudes inhérentes au système. La prise en compte de ces incertitudes est d'une importance cruciale pour la certification de tels robots utilisés pour les gestes chirurgicaux. Dans cette thèse, nous considérons un micro robot continuum à 3 actionneurs. Ce robot a été développé au laboratoire LISSI pour le traitement des anévrismes de l'aorte abdominale par chirurgie mini-invasive. Dans ce type de chirurgie, il est important de disposer d'un modèle cinématique garanti du robot continuum prenant en compte différents types d'incertitudes. Pour traiter ce problème, nous utilisons les techniques d'analyse par intervalles. Ces techniques permettent de résoudre des problèmes d'optimisation globale sous contraintes tout en prenant en compte des incertitudes aussi bien aléatoires que systématiques. La contribution de cette thèse porte sur la proposition d'un modèle cinématique d'un robot continuum prenant en compte des incertitudes liées à différents facteurs comme les erreurs d'arrondis, les erreurs paramétriques et les erreurs dues aux hypothèses de modélisation. Tout d'abord, nous développons les modèles géométriques direct et inverse du robot continuum sous forme de solutions de formes fermées. Ces solutions sont utilisées pour caractériser les différentes propriétés du robot comme la manipulabilité. Pour calculer la cinématique inverse garantie et optimale, nous appliquons une version améliorée de l'algorithme par séparation et évaluation (Branch and Bound). En considérant l'orientation du robot, la cinématique inverse est ramenée à la formulation et à la résolution par intervalles d'un problème d'optimisation sous contraintes. Les approches proposées sont validées par des simulations. Les résultats de cette thèse constituent un cadre général pour la modélisation garantie de la classe des robots continuums dont la forme est décrite par des actionneurs en flexion continueUnlike conventional robots, continuum robots do not contain any rigid link or any rotational joint but present a continuous bending in the structure through smooth motion. Development of this class of robot for their medical application presents a common set of problems : optimization of design, kinematic modeling, sensing choice, and their control in real time. Existing techniques for the modeling of continuum robots do not take system uncertainties into account. A proper handling of these uncertainties becomes of crucial importance for the certification of such robots used as medical devices. For our research, we consider a continuum robot that has been developed for the treatment of aortic aneurysm by Minimal Invasive Surgery (MIS), in LISSI Lab. In the context of MIS, it is very important to develop a guaranteed kinematic model of robot taking into account the different types of un-certainties. To handle this problem, we use the techniques of interval analysis. These techniques are capable of performing the global optimization and solving CSPs while taking into account the different uncertainties ; no matter, whether these uncertainties are random or systematic. Contribution of this thesis is proposal of a continuum robot's kinematic model that can take system uncertainties due to different factors such as rounding errors, parametric errors, and errors due to modeling assumptions. Initially, we develop the forward and inverse kinematics of the continuum robot in closed-form formulas. These derived formulas are used for the characterization of different properties of the robot such as manipulability. To find optimized guaranteed kinematics, we retained and applied an enhanced version of branch and bound algorithm. The inverse kinematics was formulated and resolved as a constrained optimization problem for robot's orientation. The proposed approaches are validated through simulations. The results of this thesis give rise to a general framework that is valid to handle the system uncertainties for the entire class of continuum robot that are shaped by continuously bending actuators
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Pompa, Federica. "Bilancio energetico ed irreversibilità in termodinamica dei continui." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/14057/.
Повний текст джерелаАнотація:
Molti sistemi fisici sono descritti, con ottima approssimazione, come sistemi continui, nei quali è trascurata la descrizione della struttura molecolare della materia costituente. La loro descrizione, tuttavia, deve essere arricchita, precisando quelle che sono tutte le altre proprietà caratterizzanti il continuo fisico, quali, ad esempio, la massa, la velocità, la temperatura e la pressione. Ciò viene fatto introducendo, nelle regioni occupate dal continuo, opportuni campi, scalari e tensoriali, corrispondenti a caratteristiche grandezze fisiche le cui leggi di bilancio sono formulate in modo tale da possedere carattere universale: valide per ogni continuo in ogni riferimento da cui lo si studia.
A livello meccanico, la trattazione del continuo fisico è basata sui concetti di volume e superficie materiali, in grado di muoversi e deformarsi nello spazio e nel tempo.
A livello termodinamico, l'impossibilità di attribuire un valore globale alle grandezze intensive di una porzione estesa di continuo non in equilibrio porta al bisogno di ripartire quest'ultima in porzioni infinitesime, ciascuna approssimativamente in equilibrio termodinamico, nelle quali i diversi campi possono essere definiti con continuità in ogni punto.
Tuttavia le sole leggi di bilancio non risultano sufficienti per studiare compiutamente il comportamento di uno specifico continuo: ad esse si affiancano le relazioni costitutive, caratteristiche di ciascun mezzo, che legano tra loro i diversi campi introdotti nella trattazione.