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1
Morand, Jules. "Dynamics of long range interacting systems beyond the Vlasov limit." Doctoral thesis, Paris 6, 2014. http://hdl.handle.net/10362/50537.
Повний текст джерелаАнотація:
Université Pierre et Marie CurieLaboratoire de Physique Nucléaire et Hautes Énergies dans le cadre de l’École Doctorale ED 389
Tese arquivada ao abrigo da Portaria nº 227/2017 de 25 de julho.
Long range interactions concern numerous natural systems. A notable example is the one of the gravitation which is relevant in the case of the study of a stars system or galaxy clusters. In particular, these systems does not respect the additivity of thermodynamical potential and present a dynamics dominated by collective effects. One of the most remarkable feature is that, after a very rapid evolution, these systems remains trapped into quasi-stationary states up to a very long time (diverging with the system size). It is only on longer time scales, that simulations have shown that the system relaxes to thermal equilibrium. Quasi-stationary states are theoretically interpreted as solutions of the Vlasov equation. This mean filed equation represents a very good approximation of the dynamics of long range systems in the limit of a large number of particles. Firstly we give a limit on the validity of the Vlasov equation depending of the range of the pair force and on its short scales regularisation. In a second part, using theoretical an numerical approach, we study the modification of the dynamics of long range systems when subjected to different kinds of non-Hamiltonian perturbations. In particular, the robustness of quasi-stationary states, in presence of this different perturbations is analysed in details.
Les interactions à longue portée concernent de nombreux systèmes naturels. Un exemple notable est celui de la gravitation newtonienne qui est pertinent dans le cas de l’étude de systèmes d’étoiles ou d’amas de galaxies. Ces systèmes ont notamment la particularité de ne pas respecter l’additivité des potentiels thermodynamiques et présentent une dynamique dominée par les effets collectifs. Une caractéristique remarquable est qu’après une évolution très rapide, ces systèmes restent piégés dans des états quasi-stationnaires pendant un temps qui peut être extrêmement grand (divergeant avec la taille du système). C’est seulement sur des échelles de temps plus longues que les simulations montrent que ces systèmes relaxent à l’équilibre thermodynamique. Les états quasi-stationnaire sont interprétés théoriquement comme les solutions stationnaires de l’équation de Vlasov. Cette équation de champs moyen représente une très bonne approximation de la dynamique macroscopique des systèmes en interaction à longue portée dans la limite où le nombre de particules tend vers l’infini. Dans un premier temps, nous nous attachons à comprendre, en fonction de la portée de la force de paire et de sa régularisation à court distance, quel est le champs de validité de cette équation, et en particulier, dans quelle cas le phénomène d’état quasi-stationnaire est attendu. Dans une seconde partie, combinant les approches théoriques et numériques, nous étudions la modification de la dynamique des systèmes à longue portée soumis à différentes sortes de perturbations non-Hamiltoniennes. La robustesse des états quasi-stationnaires en présence des différentes perturbations est analysée en détails.
2
Morand, Jules. "Dynamics of long range interacting systems beyond the Vlasov limit." Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066624/document.
Повний текст джерелаАнотація:
Les interactions à longue portée concernent de nombreux systèmes naturels. Un exemple notable est celui de la gravitation newtonienne qui est pertinent dans le cas de l'étude de systèmes d'étoiles ou d'amas de galaxies. Ces systèmes ont notamment la particularité de ne pas respecter l'additivité des potentiels thermodynamiques et présentent une dynamique dominée par les effets collectifs. Une caractéristique remarquable est qu'après une évolution très rapide, ces systèmes restent piégés dans des états quasi-stationnaires pendant un temps qui peut être extrêmement grand (divergeant avec la taille du système). C'est seulement sur des échelles de temps plus longue que les simulation montre que ces systèmes relaxent à l’équilibre thermodynamique.Les états quasi-stationnaire sont interprétés théoriquement comme les solution stationnaires de l'équation de Vlasov. Cette équation de champs moyen représente un très bonne approximation de la dynamique macroscopique des systèmes en interaction à longue portée dans la limite ou le nombre de particule tend vers l'infini. Dans une premier temps, nous nous attacherons à comprendre, en fonction de la portée de la force de paire et de sa régularisation à court distance, quel est le champs de validité de cette équation, et en particulier, dans quelle cas le phénomène d'état quasi-stationnaire est attendu.Dans une seconde partie, combinant les approches théoriques et numériques, nous étudions la modification de la dynamique des systèmes à longue portée soumis à différentes sortes de perturbation non-Hamiltonienne. La robustesse des états quasi-stationnaires en présence des différentes perturbation est analysée en détailsLong range interactions concern numerous natural systems. A notable example is the one of the gravitation which is relevant in the case of the study of a stars system or galaxy clusters. In particular, these systems does not respect the additivity of thermodynamical potential and present a dynamics dominated by collective effects. One of the most remarkable feature is that, after a very rapid evolution, these systems remains trapped into quasi-stationary states up to a very long time (diverging with the system size). It is only on longer time scales, that simulations have shown that the system relaxes to thermal equilibrium.Quasi-stationary states are theoretically interpreted as solutions of the Vlasov equation. This mean filed equation represents a very good approximation of the dynamics of long range systems in the limit of a large number of particles. Firstly we give a limit on the validity of the Vlasov equation depending of the range of the pair force and on its short scales regularisation. In a second part, using theoretical an numerical approach, we study the modification of the dynamics of long range systems when subjected to different kinds of non-Hamiltonian perturbations. In particular, the robustness of quasi-stationary states, in presence of this different perturbations is analysed in details
3
Myers, Owen Dale. "Spatiotemporally Periodic Driven System with Long-Range Interactions." ScholarWorks @ UVM, 2015. http://scholarworks.uvm.edu/graddis/524.
Повний текст джерелаАнотація:
It is well known that some driven systems undergo transitions when a system parameter is changed adiabatically around a critical value. This transition can be the result of a fundamental change in the structure of the phase space, called a bifurcation. Most of these transitions are well classified in the theory of bifurcations. Among the driven systems, spatiotemporally periodic (STP) potentials are noteworthy due to the intimate coupling between their time and spatial components. A paradigmatic example of such a system is the Kapitza pendulum, which is a pendulum with an oscillating suspension point. The Kapitza pendulum has the strange property that it will stand stably in the inverted position for certain driving frequencies and amplitudes. A particularly interesting and useful STP system is an array of parallel electrodes driven with an AC electrical potential such that adjacent electrodes are 180 degrees out of phase. Such an electrode array embedded in a surface is called an Electric Curtain (EC). As we will show, by using two ECs and a quadrupole trap it is posible to produce an electric potential simular in form to that of the Kapitza pendulum.
Here I will present the results of four related pieces of work, each focused on understanding the behaviors STP systems, long-range interacting particles, and long-range interacting particles in STP systems. I will begin with a discussion on the experimental results of the EC as applied to the cleaning of solar panels in extraterrestrial environments, and as a way to produce a novel one-dimensional multiparticle STP potential. Then I will present a numerical investigation and dynamical systems analysis of the dynamics that may be possible in an EC. Moving to a simpler model in order to explore the rudimentary physics of coulomb interactions in a STP potential, I will show that the tools of statistical mechanics may be important to the study of such systems to understand transitions that fall outside of bifurcation theory. Though the Coulomb and, similarly, gravitational interactions of particles are prevalent in nature, these long-range interactions are not well understood from a statistical mechanics perspective because they are not extensive or additive. Finally, I will present a simple model for understanding long-range interacting pendula, finding interesting non-equilibrium behavior of the pendula angles. Namely, that a quasistationary clustered state can exist when the angles are initially ordered by their index.
4
Latella, Ivan. "Statistical thermodynamics of long-range interacting systems and near-field thermal radiation." Doctoral thesis, Universitat de Barcelona, 2016. http://hdl.handle.net/10803/400405.
Повний текст джерелаАнотація:
Two main topics are examined in this thesis: classical systems with long-range interactions and thermal radiation in the near-field regime. In the first part, we present a thermodynamic approach describing systems with long-range interactions which takes into account the intrinsic nonadditivity in these systems. The basic concept behind this approach is to consider a large ensemble of replicas of the system where the standard formulation of thermodynamics can be naturally applied and the properties of a single system can be consequently inferred. The formulation of the thermodynamic for these systems is in close connection with Hill's thermodynamics of systems with small number of particles. It is shown that systems with long-range interactions can attain equilibrium configurations in the unconstrained ensemble. In this statistical ensemble, the control parameters are the temperature, pressure, and chemical potential, while the energy, volume, and number of particles fluctuate. We consider a solvable model as a concrete example of a system that achieves stable equilibria in this ensemble. We also give a complete description of the phase-diagram of the Thirring model in both the microcanonical and the canonical ensemble, highlighting the main features of ensemble inequivalence. I the second part, we study energy and entropy fluxes of near-field thermal radiation in many-body systems, with application to energy-conversion processes.
It is shown that the maximum work that can be obtained from the thermal radiation emitted by two planar sources in the near-field regime is much larger than that corresponding to the blackbody limit. This quantity as well as an upper bound for the efficiency of the process are computed from the formulation of thermodynamics in the near-field regime. The case when the difference of temperatures of the hot source and the environment is small, relevant for energy harvesting, is studied in detail. We also show that thermal radiation energy conversion can be more efficient in the near-field regime. Moreover, by analyzing the thermodynamic performance of three-body near-field heat engines, we demonstrate that the power they supply can be substantially larger than that of two-body systems, showing their strong potential for energy harvesting. Theoretical limits for energy and entropy fluxes in three-body systems are discussed and compared with their corresponding two-body counterparts. Such considerations confirm that the thermodynamic availability in energy-conversion processes driven by three-body photon tunneling can exceed the thermodynamic availability in two-body systems.En esta tesis se estudia la termodinámica y mecánica estadística de sistemas clásicos con interacciones de largo alcance y de la radiación térmica de campo cercano. En la primera parte, introducimos un formalismo termodinámico apropiado para sistemas con interacciones de largo alcance, en el cual se tiene en cuenta la no aditividad intrínseca en estos sistemas. Para estos sistemas, mostramos que la temperatura, presión y potencial químico pueden ser variables independientes. A su vez, dependiendo del sistema, lo anterior da lugar a poder tomar estas variables como parámetros de control para definir las configuraciones de equilibrio. Para estudiar este hecho, hemos introducido un modelo que cumple estas condiciones. En la segunda parte de la tesis, hemos desarrollado un esquema termodinámico para describir procesos de conversión de energía en trabajo útil en sistemas con interacción térmica radiativa en el campo cercano. Se ha mostrado explícitamente que de la radiación térmica de campo cercano puede extraerse un trabajo útil mayor que el obtenido de la radiación térmica de cuerpo negro. Hemos mostrado, además, que la potencia obtenida en sistemas con tres cuerpos en interacción puede ser considerablemente superior que en el caso de dos cuerpos.
5
Mihaylov, Petar. "Investigation of long-range interactions in the human visual system." Thesis, Glasgow Caledonian University, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.547413.
Повний текст джерела
6
Nardini, Cesare. "Energy landscapes, equilibrium and out of equilibrium physics of long and short range interacting systems." Phd thesis, Ecole normale supérieure de lyon - ENS LYON, 2013. http://tel.archives-ouvertes.fr/tel-00820555.
Повний текст джерелаАнотація:
The thesis is divided in two parts, corresponding to the two main subjects on which I have worked during my PhD. In the first Part, we introduce many-body long-range interacting systems, such as plasma and self-gravitating systems. We first review the well known properties of isolated systems, which show peculiar behaviors both for what concern the equilibrium and the relaxation to equilibrium. We then consider long-range systems driven away from equilibrium and we show how the techniques developed for isolated systems can be extended to describe these situations. Generalizations to describe simplified models relevant for geophysical flows and two-dimensional turbulence are also discussed. Our work stands at the edge between the study of long-range interacting systems and the study of non-equilibrium systems.The second part of the thesis is devoted to the study of equilibrium properties of Hamiltonian systems with energy landscape techniques. A number of recent results is reviewed and applied to long and short-range interacting systems. One of the scope of my work was to study models whose energy landscape is much more complicated than what previously done. In the case of ferromagnetic short-range O(n) models on hypercubic lattices, our analysis unveiled a striking similarity between the critical energies of the Ising model and the O(n) models defined on the same lattice with the same interaction matrix. Generalizations of the Stillinger and Weber formalism are discussed as preliminary results and future perspectives.
7
Qin, Liang. "Application of irreversible Monte Carlo in realistic long-range systems." Thesis, Université Paris sciences et lettres, 2020. http://www.theses.fr/2020UPSLE009.
Повний текст джерелаАнотація:
Cette thèse étudie le comportement de la chaîne d'événements de Monte Carlo (ECMC) dans les systèmes de particules à interaction de longue portée. Les deux premiers chapitres présentent les méthodes actuelles de simulation moléculaire, en soulignant leurs difficultés à traiter l'interaction de Coulomb, et donnent les bases de l'ECMC. Le troisième chapitre présente notre cadre d'échantillonnage du système de Coulomb à l'aide de l'ECMC. Dans le cadre de la convention "tin-foil", la formulation constituée d’interaction à deux corps pour l'électrostatique peut être appliquée directement à la méthode "cell-veto". En ajoutant à cela, la factorisation dipolaire obtient un algorithme en O(NlogN)-par-balayage pour les systèmes dipolaires. Les chapitres quatre et cinq décrivent notre développement d'une application scientifique appelée JeLLyFysh pour la simulation moléculaire par ECMC. La conception de son médiateur et le traitement de toutes les opérations en flux continu sont les mieux adaptés aux extensions futures. Le chapitre six décrit les performances de l'ECMC pour les grands systèmes d'eau à l’aide de JeLLyFysh. La dynamique qui en résulte implique qu'un schéma plus sophistiqué est nécessaire pour équilibrer la polarisation. Enfin, au chapitre sept, on teste la stratégie d'échantillonnage avec changement de direction séquentiel. L'évolution du dipôle présente une dynamique particulière, et l'ensemble des choix de direction ainsi que l'ordre de sélection s'avèrent tous deux cruciaux pour atteindre la distribution stationnaire de l'orientation du dipôleThis thesis studies the behavior of event-chain Monte Carlo (ECMC) in long-range particle systems. In the first two chapters, we introduce established methods for molecular simulation, highlighting their difficulties in dealing with Coulomb interaction, and gives the basic of ECMC. The third chapter presents our framework of Coulomb system sampling using ECMC. Under the tin-foil convention, the formulation consisting of pairwise terms for electrostatics can be directly applied to the cell-veto method. Together with dipole factorization, we obtain an O(NlogN)-per-sweep algorithm for dipole systems. Chapters four and five describe our development of a scientific application called JeLLyFysh for molecular simulation through ECMC. Its mediator design and stream processing of all operations can best accommodate future extensions. Using JeLLyFysh, we profile the performance of ECMC for large water systems in chapter six. The resulting dynamics imply that a more sophisticated scheme is needed to equilibrate the polarization. Finally, in chapter seven, we test the sampling strategy with sequential direction change. The dipole evolution exhibits distinct dynamics, and the set of direction choices and the order to select prove both crucial in mixing the dipole's orientation
8
Preto, Jordane. "Long-range interactions in biological systems." Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4053.
Повний текст джерелаАнотація:
L'auto-organisation des organismes vivants est d'une complexité et d'une efficacité étonnantes. Plus précisément, les systèmes biologiques abritent un nombre gigantesque de réactions très spécifiques qui nécessitent que la bonne biomolécule se retrouve à la bonne place, dans le bon ordre et en un temps suffisamment court pour permettre le fonctionnement cellulaire, et au-delà la vie cellulaire. D'un point de vue dynamique, cela pose la question fondamentale de savoir comment les biomolécules trouvent efficacement leur(s) cible(s) spécifique(s), ou encore, quels types de forces rassemblent tous ces partenaires de réaction spécifiques dans un environnement aussi dense et ionisé que les micro-environnements cellulaires. Dans cette thèse, nous explorons la possibilité que des biomolécules puissent interagir à travers des interactions électromagnétiques de longue-portée telles que ces dernières sont prédites à partir des premiers principes de la physique; ''longue-portée'' signifiant que les interactionsen question sont actives sur des distances bien plus larges que les dimensions typiques des molécules mises en jeu (i.e., plus grandes qu'environ 50 angströms dans les systèmes biologiques). Après avoir posé les fondements théoriques concernant les interactionsde longue-portée potentiellement actives sur de longue distances dans un contexte biologique, nous étudions la posssibilité de détecter leur éventuelle contribution à partir de dispositifs expérimentaux qui sont accessibles de nos jours. Sur ce dernier point, des résultats préliminaires encourageants tant sur le plan théorique qu'expérimental sont présentésSelf-organization of living organisms is of an astonishing complexity and efficiency. More specifically, biological systems are the site of a huge number of very specific reactions thatrequire the right biomolecule to be at the right place, in the right order and in a reasonably short time to sustain cellular function and ultimately cellular life. From the dynamic point of view, this raises the fundamental question of how biomolecules effectively find their target(s); in other words, what kinds of forces bring all these specific cognate partners together in an environment as dense and ionized as cellular micro-environments. In the present thesis, we explore the possibility that biomolecules interact through long-range electromagnetic interactions as they are predicted from the first principles of physics; "long-range" meaning that the mentioned interactions are effective over distances much larger than the typical dimensions of the molecules involved (i.e., larger than about 50 angströms in biological systems).After laying the theoretical foundations about interactions that are potentially active over long distances in a biological context, we investigate the possibility of detecting their contribution from experimental devices which are nowadays available. On the latter point, encouraging preliminary results both at the theoretical and experimental levels are exposed
9
Johnson, S. R. "Theoretical studies of systems with long-ranged interactions." Thesis, University of Cambridge, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.605655.
Повний текст джерелаАнотація:
It is demonstrated that a perturbation theory for the Coulomb Gap can be developed, which is identical to the TAP approach to spin glasses. Thus chapter 2 presents the standard theoretical method used to study the Coulomb Gap, together with the analogous result in spin-glass theory. Chapter 3 begins the exposition of new work contained in the thesis. The example of the classical dipole fluid is used to demonstrate how classical spin systems with long-ranged interactions can be expanded as a series of Feynman diagrams. A similar method, taking account of the disorder in the Coulomb Gap problem, is used to derive the strong-disorder Coulomb Gap density of states as a leading set of Feynman diagrams. In the next chapter, it is shown that the assumption of single-parameter scaling enables the use of the Renormalization Group to derive such non-perturbative effects as the crossover to weak disorder, and edge effects within the Coulomb Gap fluid. In chapter 5, it is shown that the analogy with spin glasses enables the use of the replica trick to obtain an effective field theory for the Coulomb Gap, which resembles the Sine-Gordon model in statistical physics. This resemblance allows a systematic derivation of the RG scaling function to any accuracy and a study of the renormalizability of the effective field theory, leading in principle to a test of the single-parameter scaling hypothesis. The second part of the thesis considers the optical phonons in a disordered ionic crystal, and in chapter 6 it is shown that the use of projection operators together with the standard techniques of perturbation theory enables a derivation of the phonon density of states. The result is that the longitudinal and transverse optic phonon modes are broadened by disorder into semicircular bands, and is identical to the result for the disorder-broadened Landau levels in a metal. Inspired by this similarity, methods of perturbation theory and supersymmetry have been applied to deriving the transport properties of the phonons. As described in section 7.2, the lack of a small parameter makes this impossible for the disordered ionic crystal, but the simpler problem of a uniaxial ionic crystal would be suitable for the use of these techniques.
10
Buyskikh, Anton S. "Dynamics of quantum many-body systems with long-range interactions." Thesis, University of Strathclyde, 2017. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=28798.
Повний текст джерелаАнотація:
Constantly increasing experimental possibilities with strongly correlated systems of ultracold atoms in optical lattices and trapped ions make them one of the most promising candidates for quantum simulation and quantum computation in the near future, and open new opportunities for study many-body physics. Out-of-equilibrium properties of such complex systems present truly fascinating and rich physics, which is yet to be fully understood. This thesis studies many-body dynamics of quantum systems with long-range interactions and addresses a few distinct issues. The first one is related to a growing interest in the use of ultracold atoms in optical lattices to simulate condensed matter systems, in particular to understand their magnetic properties. In our project on tilted optical lattices we map the dynamics of bosonic particles with resonantly enhanced long-range tunnelings onto a spin chain with peculiar interaction terms. We study the novel properties of this system in and out of equilibrium. The second main topic is the dynamical growth of entanglement and spread of correlations between system partitions in quench experiments. Our investigation is based on current experiments with trapped ions, where the range of interactions can be tuned dynamically from almost neighboring to all-to-all. We analyze the role of this interaction range in non-equilibrium dynamics. The third topic we address is a new method of quantum state estimation, certified Matrix Product State (MPS) tomography, which has potential applications in regimes unreachable by full quantum state tomography. The investigation of quantum many-body systems often goes beyond analytically solvable models; that is where numerical simulations become vital. The majority of results in this thesis were obtained via the Density Matrix Renormalization Group (DMRG) methods in the context of the MPS and Matrix Product Operator(MPO) formalism. Further developing and optimizing these methods made it possible to obtain eigenstates and thermal states as well as to calculate the time dependent dynamics in quenches for experimentally relevant regimes.
11
Olivier, G. J. F. (Gerrit Jacobus Francois). "Statistical thermodynamics of long-range quantum spin systems." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/20003.
Повний текст джерелаАнотація:
Thesis (MSc)--Stellenbosch University, 2012.ENGLISH ABSTRACT:In this thesis we discuss some of the anomalies present in systems with long-range interactions, for instance negative speci c heat and negative magnetic susceptibility, and show how they can be related to the convexity properties of the thermodynamic potentials and nonequivalence of ensembles. We also discuss the possibility of engineering long-range quantum spin systems with cold atoms in optical lattices to experimentally verify the existence of nonequivalence of ensembles. We then formulate an expression for the density of states when the energy and magnetisation correspond to a pair of non-commuting operators. Finally we analytically compute the entropy s( ;m) as a function of energy, , and magnetisation, m, for the anisotropic Heisenberg model with Curie-Weiss type interactions. The results show that the entropy is non-concave in terms of magnetisation under certain circumstances which in turn indicates that the microcanonical and canonical ensembles are not equivalent and that the magnetic susceptibility is negative. After making an appropriate change of variables we show that a second-order phase transition can be present at negative temperatures in the microcanonical ensemble which cannot be represented in the canonical ensemble.
AFRIKAANSE OPSOMMING: In hierdie tesis bespreek ons van die onverwagte eienskappe wat sisteme met lang afstand wisselwerkings kan openbaar, byvoorbeeld negatiewe spesi eke warmte en negatiewe magnetiese suseptibiliteit. Ons dui ook die ooreenkoms tussen hierdie gedrag en die konveksiteit van die termodinamiese potensiale en nie-ekwivalente ensembles aan. Hierna bespreek ons die moontlikheid om lang afstand kwantum spin sisteme te realiseer met koue atome in 'n optiese rooster. Daarna wys ons hoe dit moontlik is om 'n uitdrukking vir die digtheid van toestande te formuleer vir sisteme waar die energie en magnetisasie ooreenstem met operatore wat nie met mekaar kommuteer nie. Uiteindelik bepaal ons die entropie, s( ;m), in terme van die energie, , en magnetisasie, m, vir die anisotropiese Heisenberg model met Curie-Weiss tipe interaksies. Die resultate wys dat die entropie onder sekere omstandighede nie konkaaf in terme van magnetisasie is nie. Dit, op sy beurt, dui aan dat die mikrokanoniese en kanoniese ensembles nie ekwivalent is nie en dat die magnetiese suseptibiliteit negatief kan wees. Nadat ons 'n toepaslike transformasie van veranderlikes maak, wys ons dat 'n tweede orde fase-oorgang by negatiewe temperature kan plaasvind in die mikrokanoniese ensemble wat nie verteenwoordig kan word in die kanoniese ensemble nie.
12
Benetti, Fernanda Pereira da Cruz. "Relaxation and quasi-stationary states in systems with long-range interactions." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/156793.
Повний текст джерелаАнотація:
Sistemas cujos componentes interagem por meio de forças de longo alcance não-blindadas por exemplo, sistemas estelares e plasmas não-neutros têm algumas características anô- malas em relação a sistemas com forças blindadas ou de curto alcance. Além de apresentarem características termodinâmicas peculiares como calor especí co negativo e inequivalência de ensembles, sua dinâmica é predominantemente não-colisional e leva à estados quasiestacion ários fora de equilíbrio. Esses estados são notoriamente difíceis de prever dada uma condição inicial qualquer, e ainda não existe uma teoria uni cada para tratá-los. O equilíbrio termodinâmico é atingido somente após tempos longos que escalam com o tamanho do sistema, muitas vezes excedendo o tempo de vida do universo. A relaxação para o equilíbrio, portanto, tem duas escalas de tempo: uma, curta, que leva a estados quasi-estacionários fora de equilíbrio, e a segunda, longa, que leva ao equilíbrio termodinâmico. Nesta tese de doutorado, examinamos esses fenômenos aplicando modelos teóricos e simulação numérica para diferentes sistemas de interação de longo-alcance, incluindo um modelo de spins clássicos tipo XY com longo alcance, e o sistema auto-gravitante em três dimensões. Em uma segunda etapa, estudamos a relaxação para o equilíbrio termodinâmico, a relaxação colisional, através de equações cinéticas e simulação numérica. Desta forma, buscamos esclarecer os mecanismos por trás dos estados quasi-estacionários e da relaxação colisional.Systems whose components interact by unscreened long-range forces for example, stellar systems and non-neutral plasmas have characteristics that are anomalous with respect to systems with shielded or short-range forces. Besides presenting unique thermodynamic properties such as negative speci c heat and inequivalence of ensembles, their dynamics is predominantly collisionless and leads to out-of-equilibrium quasi-stationary states. These states are notoriously di cult to predict given an arbitrary initial condition, and there is still no uni ed theory to treat them. Thermodynamic equilibrium is reached only after long timescales that increase with the system size and often exceed the lifetime of the universe. Relaxation to equilibrium, therefore, has two timescales: one short, leading to outof- equilibrium quasi-stationary states, and a second, longer, which leads to thermodynamic equilibrium. In this thesis, we examine these phenomena by applying theoretical models and numerical simulation for di erent long-range interacting systems, including a model of classical XY-type spins with long-range interactions, and the self-gravitating system in three dimensions. In a second stage we study the collisional relaxation to thermodynamic equilibrium through kinetic equations and numerical simulation. We thus seek to clarify the mechanisms behind the quasi-stationary states and collisional relaxation.
13
Botzung, Thomas. "Study of strongly correlated one-dimensional systems with long-range interactions." Thesis, Strasbourg, 2019. http://www.theses.fr/2019STRAF062.
Повний текст джерелаАнотація:
Durant cette thèse, nous étudions des systèmes unidimensionnels avec des couplages longue-portée. Dans la première partie, nous démontrons que ces couplages entraînent une décroissance algébrique des corrélations dans des fils quantiques désordonnés. Deuxièmement, nous analysons un modèle étendu de Hubbard où les particules interagissent via un potentiel « soft-core » générant de nouvelles phases exotiques. Dans le troisième chapitre, nous démontrons que restaurer l’extensivité a une influence sur les propriétés de basse énergie de modèle quantique dans la limite thermodynamique. Finalement, nous présentons des résultats préliminaires sur la modification de la localisation d’Anderson en présence d’un couplage avec une cavitéDuring this Ph.D., we studied one-dimensional systems with long-range couplings. In the first part, we demonstrate that power-law couplings lead to an algebraic decay of correlations at long distances in disordered quantum wires. In the second chapter, we analysed an extended Hubbard model where particles interact via a finite-range potential that induces frustration and new exotic phases. In the third chapter, we demonstrated that restoring energy extensivity has an influence on the low-energy properties of quantum model in the thermodynamic limit. Finally, we provide preliminary results on the modification of Anderson localization due to the coupling to a cavity mode
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Botzung, Thomas <1993>. "Study of strongly correlated one-dimensional systems with long-range interactions." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amsdottorato.unibo.it/9485/1/Botzung_Thomas_2019_PdH_tesi.pdf.
Повний текст джерелаАнотація:
During this Ph.D, we studied one-dimensional systems with long-range couplings. In the first part, we demonstrate that power-law couplings lead to an algebraic decay of correlations at long distances in disordered quantum wires. In the second chapter, we analyzed an extended Hubbard model where particles interact via a finite-range potential that induces frustration and new exotic phases. In the third chapter, we demonstrated that restoring energy extensivity has an influence on the low-energy properties of quantum model in the thermodynamic limit. Finally, we provide preliminary results on the modification of Anderson localization due to the coupling to a cavity mode.Durant cette thèse, nous étudions des systèmes unidimensionnels avec des couplages longue-portée. Dans la première partie, nous démontrons que ces couplages entraînent une décroissance algébrique des corrélations dans des fils quantiques désordonnés. Deuxièmement, nous analysons un modèle étendu de Hubbard où les particules interagissent via un potentiel « soft-core » générant de nouvelles phases exotiques. Dans le troisième chapitre, nous démontrons que restaurer l’extensivité a une influence sur les propriétés de basse énergie de modèle quantique dans la limite thermodynamique. Finalement, nous présentons des résultats préliminaires sur la modification de la localisation d’Anderson en présence d’un couplage avec une cavité.
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Jenkinson, Ashley. "Long range wireless power monitoring system." Thesis, Jenkinson, Ashley (2012) Long range wireless power monitoring system. Other thesis, Murdoch University, 2012. https://researchrepository.murdoch.edu.au/id/eprint/13121/.
Повний текст джерелаАнотація:
This thesis examines the design, construction and implementation of a microcontroller-based long range wireless power monitoring system, suitable for both domestic and industrial use. At its core, the system is based on a number of PICAXE 20X2 microcontrollers and a pair of XBee Pro wireless modules, which are capable of wireless communication to distances exceeding 1.5km.
The Long Range Wireless Power Monitoring system is capable of galvanically isolated single and three-phase current and voltage measurements and is able to calculate real power, apparent power and power factor. The results can be displayed numerically or graphically on a Graphical Liquid Crystal Display. In addition to this, the system has the ability to log usage to an external USB Flash device, allowing for later analysis and for the building of a usage history library.
The Long Range Wireless Power Monitor is equally proficient at measuring power consumption of devices, or power generation from sources such as photovoltaic cells or wind turbines. In the example of power consumption, usage costs are calculated from user-defined tariffs. Conversely, for generation, the income from power generated is calculated.
At the completion of this project, the Wireless Power Monitor is capable of being deployed for use as a fully working prototype. In addition to this, the system provides a solid basis for future adaptation or expansion and due to its open source software can be easily modified for use in specific applications.
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De, Nigris Sarah. "Influence of Network topology on the onset of long-range interaction." Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4718.
Повний текст джерелаАнотація:
Dans cette thèse, nous discutons l'influence d'un réseau qui possède une topologie non triviale sur les propriétés collectives d'un modèle hamiltonien pour spins,le modèle $XY$, défini sur ces réseaux.Nous nous concentrons d'abord sur la topologie des chaînes régulières et du réseau Petit Monde (Small World), créé avec le modèle Watt- Strogatz.Nous contrôlons ces réseaux par deux paramètres $\gamma$, pour le nombre d' interactions et $p$, la probabilité de ré-attacher un lien aléatoirement.On définit deux mesures, le chemin moyen $\ell$ et la connectivité $C$ et nous analysons leur dépendance de $(\gamma,p)$.Ensuite,nous considérons le comportement du modèle $XY$ sur la chaîne régulière et nous trouvons deux régimes: un pour $\gamma<1,5$,qui ne présente pas d'ordre longue portée et un pour $\gamma>1,5$ où une transition de phase du second ordre apparaît.Nous observons l'existence d'un état métastable pour $\gamma_ {c} = 1,5$. Sur les réseaux Petit Monde,nous illustrons les conditions pour avoir une transition et comment son énergie critique $\varepsilon_{c}(\gamma,p)$ dépend des paramètres $(\gammap$).Enfin,nous proposons un modèle de réseau où les liens d'une chaîne régulière sont ré-attachés aléatoirement avec une probabilité $p$ dans un rayon spécifique $r$. Nous identifions la dimension du réseau $d(p,r)$ comme un paramètre crucial:en le variant,il nous est possible de passer de réseaux avec $d<2$ qui ne présentent pas de transition de phase à des configurations avec $d>2$ présentant une transition de phase du second ordre, en passant par des régimes de dimension $d=2$ qui présentent des états caractérisés par une susceptibilité infinie et une dynamique chaotiqueIn this thesis we discuss the influence of a non trivial network topology on the collective properties of an Hamiltonian model defined on it, the $XY$ -rotors model. We first focus on networks topology analysis, considering the regular chain and a Small World network, created with the Watt-Strogatz model. We parametrize these topologies via $\gamma$, giving the vertex degree and $p$, the probability of rewiring. We then define two topological parameters, the average path length $\ell$and the connectivity $C$ and we analize their dependence on $\gamma$ and $p$. Secondly, we consider the behavior of the $XY$- model on the regular chain and we find two regimes: one for $\gamma<1.5$, which does not display any long-range order and one for $\gamma>1.5$ in which a second order phase transition of the magnetization arises. Moreover we observe the existence of a metastable state appearing for $\gamma_{c}=1.5$. Finally we illustrate in what conditions we retrieve the phase transition on Small World networks and how its critical energy $\varepsilon_{c}(\gamma,p)$ depends on the topological parameters $\gamma$ and $p$. In the last part, we propose a network model in which links of a regular chain are rewired according to a probability $p$ within a specific range $r$. We identify a quantity, the network dimension $d(p,r)$ as a crucial parameter. Varying this dimension we are able to cross over from topologies with $d<2$ exhibiting no phase transitions to ones with $d>2$ displaying a second order phase transition, passing by topologies with dimension $d=2$ which exhibit states characterized by infinite susceptibility and macroscopic chaotic dynamical behavior
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Toh, Han Shih. "The effect of anisotropic long-range interactions on pure and random-field systems." Thesis, University of Oxford, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292564.
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Ogawa, Shun. "Study on non-equilibrium quasi-stationary states for Hamiltonian systems with long-range interaction." 京都大学 (Kyoto University), 2013. http://hdl.handle.net/2433/180471.
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Turchi, Alessio. "Dynamics and statistics of systems with long range interactions : application to 1-dimensional toy-models." Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4810/document.
Повний текст джерелаАнотація:
L'objectif de ce thèse est l'étude des systèmes dynamiques avec interaction à longue portée. La complexité de leur dynamique met en évidence des propriétés contre-intuitives et inattendues, comme l'existence d'états stationnaires hors-équilibre (QSS). Dans le QSS on peut observer des propriétés particulières: chaleur spécifique négative, inéquivalence des ensembles statistiques et phénomènes d'auto-organisation. Les théories des interactions LR ont été appliquées pour décrire la dynamique des systèmes auto-gravitants, de tourbillons bidimensionnels, de systèmes avec interactions onde-particule et des plasmas chargés. Mon travail s'est tout d'abord consacré à l'extension de la solution de Lynden-Bell pour le modèle HMF, en généralisant l'analyse à des conditions initiales de «water-bag" à plusieurs niveaux, qui approchent des conditions initiales continues. En suite je me suis intéressé à la caractérisation formelle de la thermodynamique des QSS dans l'ensemble statistique canonique. En appliquant la théorie standard, il est possible de mesurer une chaleur spécifique "cinétique'' négative. Cette propriété inattendue amène à la violation du second principe de la thermodynamique. Un tel résultat nous pousse à reconsidérer l'applicabilité de la théorie thermodynamique actuelle aux systèmes LR. En suite j'ai étudié, pour le modèle α-HMF, la persistance des caractéristiques typiques du régime LR, dans le limite dynamique à courte portée. Les résultats suggèrent une généralisation de la définition des systèmes LR. Le dernier chapitre est consacré à la caractérisation d'un nouveau modèle LR, extension naturelle du précédent α-HMF et d'intérêt potentiel applicatifThe scope of this thesis is the study of systems with long-range interactions (LR). The complexity of their dynamics evidences counter-intuitive and unexpected properties, as for instance the existence of out-of-equilibrium stationary states (QSS). Considering a system in the QSS, one may observe peculiar properties, as negative specific heat, statistical ensemble inequivalence and phenomena of self-organizations. The main theories of long-range interactions have been applied to describing self-gravitating systems, two-dimensional vortices, systems with wave-particle interactions and charged plasmas. My work has been initially dedicated to extending the Lynden-Bell solution for the HMF model, generalizing the analysis to multi-level water-bag initial condition that could approximate continuous distributions. Then I concentrated to the formal characterization of the thermodynamics of QSS in the canonical statistical ensemble. By applying the standard theory, it is possible to measure negative “kinetic” specific heat. This latter unexpected property leads to a violation of the second principle of thermodynamics. Such result forces us to reconsider the applicability of the accepted thermodynamic theory to LR systems. Afterwards I studied, in the context of the α-HMF model, the persistence of the typical characteristics of the LR regime in the limit of short-range dynamics. The results obtained suggests a generalization of the definition of LR systems. The last chapter is dedicated to the characterization of a novel LR model, a natural extension of α-HMF and of potential applicability
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Hadjicostas, Thyrsos Panayiotis. "Long-range power system planning with load management options." Thesis, Queen Mary, University of London, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267634.
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Heidari, Maziar [Verfasser]. "Development and Application of Hamiltonian Adaptive Resolution Simulations for Systems having Long-range Interactions / Maziar Heidari." Mainz : Universitätsbibliothek Mainz, 2019. http://d-nb.info/1196112134/34.
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Roelly, Sylvie, and Michel Sortais. "Space-time asymptotics of an infinite-dimensional diffusion having a long- range memory." Universität Potsdam, 2004. http://opus.kobv.de/ubp/volltexte/2006/670/.
Повний текст джерелаАнотація:
We develop a cluster expansion in space-time for an infinite-dimensional system of interacting diffusions where the drift term of each diffusion depends on the
whole past of the trajectory; these interacting diffusions arise when considering the Langevin dynamics of a ferromagnetic system submitted to a disordered external magnetic field.
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Kim, Daeyoung. "Propagation measurements and system design for long-range RF tags." Diss., Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/13876.
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Lindy, Fred L. "Differential solutions using long-range, dual-frequency GPS correction data." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2002. http://library.nps.navy.mil/uhtbin/hyperion-image/02sep%5FLindy.pdf.
Повний текст джерелаАнотація:
Thesis (M.S. in Operations Research)--Naval Postgraduate School, September 2002.Thesis advisor(s): James R. Clynch, James N. Eagle, Samuel E. Buttrey. Includes bibliographical references (p. 77-79). Also available online.
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Khan, Zeashan Hameed. "Wireless network architecture for long range teleoperation of an autonomous System." Grenoble INPG, 2010. http://www.theses.fr/2010INPG0134.
Повний текст джерелаАнотація:
La téléopération en réseau est une thématique émergente, où un humain (le maître) communique avec un esclave commandé à distance à travers un réseau de communication, pour l'échange des données de commande et de mesure. Pour la téléopération longue distance, ces informations traversent divers réseaux hétérogènes ou hybrides interconnectés ensemble. Nous traitons également le cas où un segment sera sans fil, ce qui permet d'envisager que l'esclave soit mobile (véhicule télé-opéré par exemple). Une étude indépendante des aspects commande et des aspects réseau entraîne l'atteinte d'objectifs locaux, qui peuvent le cas échéant être ensuite fortement dégradés après l'intégration des deux aspects. L'utilisation de réseaux partagés, comme internet, en lieu et place d'une liaison dédiée (point à point, liaison virtuelle) est également un défi, en particulier dans le cas de la longue distance. Les mécanismes de qualité de service (QdS) d'un réseau, en particulier du réseau hétérogène, doivent pouvoir être traités par les autres réseaux ; ces points sont assez souvent traités avec un point de vue d'applications multimedia, plus rarement avec le point de vue de la téléopération critique. L'approche de téléopération en réseau peut profiter de ces mécanismes de qualité de service en utilisant des priorités ou des réservations de bandes passantes en fonction des critères de commande et de transparence. Cela peut entraîner une adaptation des ressources réseau en fonction des besoins des objectifs de téléopération afin de transporter l'information en satisfaisant les besoins bout en bout de l'application, cette notion devant être précisée. Lorsqu'on considère la QdS avec un point de vue réseau, elle consiste principalement à la gestion de flux de communication, en prenant en compte des paramètres de besoin et d'ordonnancement. Si l'on prend en compte le point de vue de la téléopération, la QdS entraîne des conséquences sur la qualité de commande (QdC) ce qui inclut la stabilité, la transparence et la téléprésence. De plus, l'interface humaine peut également avoir des besoins spécifiques en termes de téléprésence, ce qui peut entraîner des conséquences sur la répartition de la charge du réseau. Afin d'intégrer les deux approches de QdS et de QdC pour apporter une meilleure réponse au problème posé, nous proposons une approche de coconception avec d'une part une adaptation de la QdS aux besoins de la Qdc (qualité de la transparence) et d'autre part une adaptation de la Qdc (par exemple dégradation de la qualité du flux vidéo) à la disponibilité du réseau. Nous avons considéré deux cas de figures. Dans un premier temps, sans tenir compte des mécanismes de QdS du réseau (approche dite du meilleur effort ou best effort) et par l'adaptation au mieux de l'application, pour répondre aux besoins de la téléopération. La seconde approche considère un réseau orienté QdS entre le maître et l'esclave, où différentes priorités peuvent être attribuées aux flux nécessaires à la téléopération, en fonction des contextes. L'approche proposée est finalement mise en oeuvre sur NeCS-Car, la voiture téléopérée disponible au LaboratoireNetworked teleoperation (NT) is an emerging area of technology, where human assisted Master and remote Slave devices communicate over a communication network for the exchange of command and sensor feedback information. For long range mobile teleoperation, this information travels over different types of heterogeneous/hybrid networks interconnected together with a compulsory network segment over wireless to permit increased mobility. The independent design of control and network promotes the isolated objectives and the performance is degraded after an integration. It is also challenging if internet is used for teleoperation, instead of point to point communication. The mechanisms of QoS in one network protocol of the heterogeneous network needs mapping on any other network which is usually carried out with a multimedia point of view and not for the critical teleoperation data. The approach for networked teleoperation can be given a new dimension by adding quality of service (QoS) to different flows on need based priority and as a function of control and transparence criteria. This means to alter the network resources for teleoperation objective in order to transport the information to satisfy the end-to-end application needs. The network QoS perspective is important to consider in the co-design approach for teleoperation. However, the true meaning of end to end QoS must be defined for teleoperation. If we consider the QoS from the network point of view, it refers to the management of various flows or users as per their need and precedence. Whereas, from the teleoperation perspective, QoS is related to the quality of control (QoC) which includes stability, transparence and telepresence. Moreover, the human interface may have different requirements as per telepresence feeling which will result in varying network load. To control network QoS, we need to measure or estimate it. Therefore, classification of QoS is performed with a fuzzy inference system which is able to distinguish between varying levels of QoS. In addition, it is also a challenging task for online decision for reconfiguration of network and control performance. We have used supervised methods for classification and prediction of QoS to be used in the proposed approach. Thus, data communication networks treat control information as best effort most of the time. Conclusion the communication used in teleoperation uses a dedicated network/communication. In short, a co-design approach is formulated to treat the network QoS as a function of teleoperation objectives which are related to the quality of transparence and control. Alternatively, the video flow is managed in order to effectively reduce the necessary throughput for instants when the network quality is not sufficient. We have considered two cases. First, without taking into account any network QoS mechanism (best effort flows only) and adapting application needs as per the teleoperation objectives. The second one considers a QoS oriented network in between the master and slave, where different priorities can be assigned to the teleoperation flows as per need. In the end, the proposed methodology is implemented on the NeCS-Car benchmark
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Hagan, James D. "Development of a long-range naval gun : a system engineering approach /." Master's thesis, This resource online, 1995. http://scholar.lib.vt.edu/theses/available/etd-12232009-020246/.
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Teles, Tarcisio Nunes. "Mecânica estatística em sistemas com interações de longo alcance : estados estacionários e equilíbrio." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2012. http://hdl.handle.net/10183/55450.
Повний текст джерелаАнотація:
Desde os trabalhos de Clausius, Boltzmann e Gibbs, sabe-se que partículas que interagem através de potenciais de curto alcance alcançam, após um processo de relaxação, o estado final estacionário que corresponde ao equilíbrio termodinâmico [I]. Embora nenhuma prova exata exista para isso, na prática, verifica-se que os sistemas não-integráveis com uma energia fixa e um número finito de partículas (ensemble microcanônico, por exemplo) sempre relaxam para um estado estacionário que só depende de quantidades globais conservadas pela dinâmica: energia, momentum e momentum angular. Este estado estacionário corresponde ao estado de equilíbrio termodinâmico e não depende das especificidades da distribuição inicial de partículas. Este cenário muda drasticamente quando a interação entre as partículas passa a ser de longo alcance [2]. A descrição estatística e termodinâmica desses sistemas ainda é objeto de estudo. Contudo, o que se sabe é que esses sistemas têm como propriedade fundamental o fato de que, no limite termodinâmico o tempo de colisão diverge e o equilíbrio termodinâmico nunca é atingido [3]. Nesse trabalho analisamos do ponto de vista teórico e por simulação de dinâmica molecular o estado estacionário atingido por sistemas auto-gravitantes em uma, duas e três dimensões e plasmas não-neutros na dinâmica de um feixe de partículas carregadas. Analisamos ainda um modelo com transição de fases para o estado fora do equilíbrio (HMF). Em todos os casos a teoria proposta na tese mostrou-se consistente com os simulações numéricas empregadas.Since the work of Clausius, Boltzmann and Gibbs, it is known that particles interacting by a short-range potential, after a relaxation process, reach a final stationary state that corresponds to thermodynamic equilibrium. Although no exact proof exists, in practice non-integrable systems with fixed energy and a finite number of particles (i.e., microcanonical ensemble) always relax to a stationary state that depends only on global quantities conserved by the dynamics: energy, momentum and angular momentum. This stationary state corresponds to the state of thermodynamic equilibrium and does not depend on the specifics of the initial particle distribution. This scenario changes drastically when the interaction between particles is longranged [2] The statistical and thermodynamic description of these systems is still an object of study. However, a fundamental property of these systems is the fact that, in the thermodynamic limit, the collision time diverges and thermodynamic equilibrium is never achieved [3].. In this thesis we analyse, from a theoretical point of view and using molecular dynamics simulations, the stationary state achieved by self-gravitating systems in one, two and three dimensions and non-neutral plasmas in the dynamics of charged particle beams. We also analyse a model with out-of-equilibrium phase transitions (HMF). In all these cases, the theory proposed in this thesis is shown to be consistent with the numerical simulations applied.
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Nykvist, Kim. "Underwater probe for deep sea exploration : Long range acoustic underwater communication system." Thesis, Luleå tekniska universitet, Institutionen för system- och rymdteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-80474.
Повний текст джерелаАнотація:
This was a thesis that was commissioned by Researcher Peter Sigray at the Royal Institute of Technology (KTH) in Stockholm and was based on an idea by Professor Thomas Rossby, University of Rhode Island (URI). The idea was to further develop the existing Expendable Bathythermograph (XBT), which has been in use since the 1960s. This by first and foremost replacing existing transfer technology, which involved using a thin copper wire when communicating with the recipient remaining on the ship. The new way in which communication is to take place, is by acoustic signals transmitted from the freely descending probe. The goal is to be able to measure down to greater depth compared to the previous type. The aim is to increase today's in-depth measuring capacity of about 900 meters, down to depth of at least 2000 meters, preferably even deeper. The thesis project was divided into several smaller parts, some of which went on in parallel, while others had to have the preceding portion completed, in order for them to take place, i.e., to begin. Initially – and in parallel during the rest of the thesis work – their were studies of two selected books and a set of documents. This to ensure the understanding of all the concepts to be used during the development of the probe. In parallel with the studies, simulations in the computer program COMSOL Multiphysics began. The model probe geometry and material parameters were programmed. An important task was to implement and verify that the so called Perfectly Matched Layer (PML) performed as expected. This was of crucial importance, as different implementations of the PML turned out to result in different outcomes of the simulations’ data. With the results from Perfectly Matched Layer tests verified, the actual simulations could be initiated. Two different pipes were evaluated; one made of stainless steel and the other made of aluminum alloy. Their proportions were slightly different regarding diameter and length. The simulations led to the makings of plots/diagrams over the Transmission Voltage Response (TVR) over a certain frequency range (3000-17000 Hz). Directivity polar plots were also created for both pipes in the program MATLAB and by using a MATLAB. The actual assessment of the probes began in the latter part of the simulation work. There were several different steps in the process of assembling the probes. Finally, the tests in the water tank at The Defense Research Institute (FOI) could take place. For three days all the simulated results were “put to test.” The results during the tests in the water tank at FOI were promising and the remaining challenges, before a complete probe is developed, are achievable. The hypothesis that initially was set got proven, and it can be argued that the thesis as a whole successfully demonstrated it to be true. The idea of the probe is definitely worth further development, in the making of the new version of the Expendable Bathythermograph.
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Lang, Johannes [Verfasser], Wilhelm [Akademischer Betreuer] Zwerger, Wilhelm [Gutachter] Zwerger, and Michael [Gutachter] Hartmann. "Non-equilibrium Phase Transitions in Systems with long-range Interactions / Johannes Lang ; Gutachter: Wilhelm Zwerger, Michael Hartmann ; Betreuer: Wilhelm Zwerger." München : Universitätsbibliothek der TU München, 2019. http://d-nb.info/1194162819/34.
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Heinig, Peter. "The geometry of interacting liquid domains in Langmuir monolayers." Phd thesis, [S.l. : s.n.], 2003. http://pub.ub.uni-potsdam.de/2003/0019/heinig.pdf.
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Shah, Dhaval. "DELAY MODELING AND LONG-RANGE PREDICTIVE CONTROL OF CZOCHRALSKI GROWTH PROCESS." Doctoral diss., University of Central Florida, 2009. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2118.
Повний текст джерелаАнотація:
This work presents the Czochralski growth dynamics as time-varying delay based model, applied to the growth of La3Ga5.5Ta0.5O14 (LGT) piezoelectric crystals. The growth of high-quality large-diameter oxides by Czochralski technique requires the theoretical understanding and optimization of all relevant process parameters, growth conditions, and melts chemistry. Presently, proportional-integral- derivative (PID) type controllers are widely accepted for constant-diameter crystal growth by Czochralski. Such control systems, however, do not account for aspects such as the transportation delay of the heat from crucible wall to the crystal solidification front, heat radiated from the crucible wall above the melt surface, and varying melt level. During crystal growth, these time delays play a dominant role, and pose a significant challenge to the control design. In this study, a time varying linear delay model was applied to the identification of nonlinearities of the growth dynamics. Initial results reveled the benefits of this model with actual growth results. These results were used to develop a long-range model predictive control system design. Two different control techniques using long range prediction are studied for the comparative study. Development and testing of the new control system on real time growth system are discussed in detail. The results are promising and suggest future work in this direction. Other discussion about the problems during the crystal growth, optimization of crystal growth parameters are also studied along with the control system design.Ph.D.
School of Electrical Engineering and Computer Science
Engineering and Computer Science
Electrical Engineering PhD
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Poulin, Jason Eric. "Concept design of a long range AUV propulsion system with an onboard electrical generator." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/74938.
Повний текст джерелаАнотація:
Thesis (S.M. in Naval Architecture and Marine Engineering)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 104-107).
Automated Underwater Vehicle (AUV) Technology has come a long way in the past decade. Due to advances in batteries and telecommunications, unmanned underwater vehicles no longer require a tether to a mother ship for power, command and control. AUV endurance and range, however, are still limited by the size and capacity of the onboard batteries. Attempts to overcome this limitation, with studies utilizing fuel and solar cells were developed to augment the stored energy onboard. This thesis examines the viability of utilizing an internal combustion engine as an onboard generator to recharge the batteries in during the mission in order to increase both range and endurance. Working in conjunction with the MIT Rapid Development Group, an onboard generating system was developed utilizing a gasoline generator. This system was incorporated into in a clean sheet propulsion system design of a long range AUV propulsion system. Maximum efficiency of all components was stressed at every point in the design process in order to decrease the propulsion system power requirements. Advanced lithium-ion battery systems were also investigated in order to find a system that balanced maximal energy storage with low recharge time. The study resulted in a theoretical AUV propulsion system that could traverse distances that span the Atlantic Ocean at a speed of 2 kts. It is believed that this type of AUV would be ideal for both scientific research and military applications.
by Jason Eric Poulin.
S.M.
S.M.in Naval Architecture and Marine Engineering
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Mitchell, David. "A long-range spectroscopic methane leak sensor system using a high power raman amplifier." Thesis, University of Strathclyde, 2010. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=12841.
Повний текст джерела
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Lin, Tianhong, and Тяньхун Лінь. "Preliminary design of long range cargo aircraft with 240 passengers." Thesis, National Aviation University, 2021. https://er.nau.edu.ua/handle/NAU/53188.
Повний текст джерелаАнотація:
Робота публікується згідно наказу Ректора НАУ від 27.05.2021 р. №311/од "Про розміщення кваліфікаційних робіт здобувачів вищої освіти в репозиторії університету". Керівник роботи: доцент, к.т.н. Юцкевич Святослав СергійовичThis diploma work is dedicated to the design of cargo long-range aircraft with passenger capacity 240 and its design characteristic estimation. The methods of design are analysis of the prototypes and selections of the most advanced technical decisions, analysis of center of gravity position. The diploma work contains drawings of the long-range aircraft with a carrying capacity of 240 passengers, calculations and drawings of the aircraft layout.
Дана дипломна робота присвячена конструюванню вантажного дальньомагістрального літака з пасажиромісткістю 240 пасажирів та його проектних характеристик. Методами проектування є аналіз прототипів і вибір найсучасніших технічних рішень, аналіз положення центру ваги. Дипломна робота містить креслення дальньомагістрального літака пасажиромісткістю 240 пасажирів, розрахунки та креслення компоновки літака.
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Walker, Peter Francis. "New approaches to radio system design to exploit multiple propagation mechanisms over long-range paths." Thesis, University of Hull, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389470.
Повний текст джерела
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Abouzahra, Mohamed D., Frank C. Robey, and Scott Henion. "PHOTONIC REMOTING OF THE KWAJALEIN MISSILE RANGE POST IMPACT TELEMETRY SYSTEM." International Foundation for Telemetering, 1999. http://hdl.handle.net/10150/607308.
Повний текст джерелаАнотація:
International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, NevadaThis paper describes the design, configuration, testing, and performance of a Fiber Optic Link used to transmit the signals from a remotely located S-band telemetry system to the main facility at the Kwajalein Missile Range (KMR). This fiber optic system demonstrates for the first time the feasibility of linking RF data from multiple antennas via a single fiber and over a nearly 100-km distance. Measured data of key link parameters such as gain, bit-error-rate, crosstalk, phase and gain stability, dynamic range, and noise figure are presented.
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Guest, Jason Michael [Verfasser]. "Structural and functional principles of long-range connectivity in the rat vibrissal system / Jason Michael Guest." Bonn : Universitäts- und Landesbibliothek Bonn, 2020. http://d-nb.info/1222588773/34.
Повний текст джерела
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Gandikota, Vijai. "Modeling operating system crash behavior through multifractal analysis, long range dependence and mining of memory usage patterns." Morgantown, W. Va. : [West Virginia University Libraries], 2006. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=4566.
Повний текст джерелаАнотація:
Thesis (M.S.)--West Virginia University, 2006.Title from document title page. Document formatted into pages; contains xii, 102 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 96-99).
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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.
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Luusua, Emil. "Vehicle Detection, at a Distance : Done Efficiently via Fusion of Short- and Long-Range Images." Thesis, Linköpings universitet, Datorseende, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-167073.
Повний текст джерелаАнотація:
Object detection is a classical computer vision task, encountered in many practical applications such as robotics and autonomous driving. The latter involves serious consequences of failure and a multitude of challenging demands, including high computational efficiency and detection accuracy. Distant objects are notably difficult to detect accurately due to their small scale in the image, consisting of only a few pixels. This is especially problematic in autonomous driving, as objects should be detected at the earliest possible stage to facilitate handling of hazardous situations. Previous work has addressed small objects via use of feature pyramids and super-resolution techniques, but the efficiency of such methods is limited as computational cost increases with image resolution. Therefore, a trade-off must be made between accuracy and cost. Opportunely though, a common characteristic of driving scenarios is the predominance of distant objects in the centre of the image. Thus, the full-frame image can be downsampled to reduce computational cost, and a crop can be extracted from the image centre to preserve resolution for distant vehicles. In this way, short- and long-range images are generated. This thesis investigates the fusion of such images in a convolutional neural network, particularly the fusion level, fusion operation, and spatial alignment. A novel framework — DetSLR — is proposed for the task and examined via the aforementioned aspects. Through adoption of the framework for the well-established SSD detector and MobileNetV2 feature extractor, it is shown that the framework significantly improves upon the original detector without incurring additional cost. The fusion level is shown to have great impact on the performance of the framework, favouring high-level fusion, while only insignificant differences exist between investigated fusion operations. Finally, spatial alignment of features is demonstrated to be a crucial component of the framework.
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Turabi, Ali, and Алі Абутураб Торабі. "Preliminary design of a long-range passenger aircraft with a 364 passenger capacity." Thesis, National Aviation University, 2021. https://er.nau.edu.ua/handle/NAU/53185.
Повний текст джерелаАнотація:
Робота публікується згідно наказу Ректора НАУ від 27.05.2021 р. №311/од "Про розміщення кваліфікаційних робіт здобувачів вищої освіти в репозиторії університету". Керівник роботи: доцент, к.т.н. Юцкевич Святослав СергійовичThis diploma work is dedicated to preliminary design of the long-range aircraft with 364 passenger capacity. The process of development is analysis of the prototypes and selections of the most progressive involve decisions. The diploma work has drawings of project of the long-range airplane with 364 passenger capacity, calculations and drawings of the aircraft layout.
Ця дипломна робота присвячена ескізному проекту дальньомагістрального літака на 364 пасажири. Процес розробки - це аналіз прототипів і відбір найбільш прогресивних рішень. Дипломна робота містить креслення проекту дальньомагістрального літака на 364 пасажири, розрахунки та креслення компоновки літака.
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Sharifzadeh, Shayan. "Design Optimization and Analysis of Long-Range Hydrogen-Fuelled Hypersonic Cruise Vehicles." Doctoral thesis, Universite Libre de Bruxelles, 2017. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/255764.
Повний текст джерелаАнотація:
Aviation industry is continuously growing especially for very long distance flights due to the globalisation of local economies around the world and the explosive economic growth in Asia. Reducing the time of intercontinental flights from 16-20 hours to 4 hours or less would therefore make the, already booming, ultra-long distance aviation sector even more attractive. To accomplish this drastic travel time reduction for civil transport, hypersonic cruise aircraft are considered as a potential cost-effective solution. Such vehicles should also be fuelled by liquid hydrogen, which is identified as the only viable propellant to achieve antipodal hypersonic flight with low environmental impact. Despite considerable research on hypersonic aircraft and hydrogen fuel, several major challenges should still be addressed before such airliner becomes reality. The current thesis is therefore motivated by the potential benefit of hydrogen-fuelled hypersonic cruise vehicles associated with their limited state-of-the-art.Hypersonic cruise aircraft require innovative structural configurations and thermal management solutions due to the extremely harsh flight environment, while the uncommon physical properties of liquid hydrogen, combined with high and long-term heat fluxes, introduce complex design and technological storage issues. Achieving hypersonic cruise vehicles is also complicated by the multidisciplinary nature of their design. In the scope of the present research, appropriate methodologies are developed to assess, design and optimize the thermo-structural model and the cryogenic fuel tanks of long-range hydrogen-fuelled hypersonic civil aircraft. Two notional vehicles, cruising at Mach 5 and Mach 8, are then investigated with the implemented methodologies. The design analysis of light yet highly insulated liquid hydrogen tanks for hypersonic cruise vehicles indicates an optimal gravimetric efficiency of 70-75% depending on insulation system, tank wall material, tank diameter, and flight profile. A combination of foam and load-bearing aerogel blanket leads to the lightest cryogenic tank for both the Mach 5 and the Mach 8 aircraft. If the aerogel blanket cannot be strengthened sufficiently so that it can bear the full load, then a combination of foam and fibrous insulation materials gives the best solution for both vehicles. The aero-thermal and structural design analysis of the Mach 5 cruiser shows that the lightest hot-structure is a titanium alloy construction made of honeycomb sandwich panels. This concept leads to a wing-body weight of 143.9 t, of which 36% accounts for the wing, 32% for the fuselage, and 32% for the cryogenic tanks. As expected, hypersonic thermal loads lead to important weight penalties (of more than 35%). The design of the insulated cold structure, however, demonstrates that the long-term high-speed flight of the airliner requires a substantial thermal protection system, such that the best configuration (obtained by load-bearing aerogel blanket) leads to a titanium cold design of only 4% lighter than the hot structure. Using aluminium 7075 rather than titanium offers a further weight saving of about 2%, resulting in a 135.4 t wing-body weight (with a contribution of 23%, 25%, 18% and 34% from the TPS, the wing, the fuselage, and the cryogenic tanks respectively). Given the design hypotheses, the difference in weight is not significant enough to make a decisive choice between hot and cold concepts. This requires the current methodologies to be further elaborated by relaxing the simplifications. Investigation of the thermal protection must be extended from one single point to different regions of the vehicle, and the TPS thickness and weight should be considered in the structural sizing of the cold design. More generally, the design process should be matured by including additional (static, dynamic and transient) loads, special structural concepts, multi-material configurations and other parameters such as cost and safety aspects.Doctorat en Sciences de l'ingénieur et technologie
This thesis was conducted in co-tutelle between University of Sydney and Université Libre de Bruxelles.Professor Dries Verstraete was my supervisor at the University of Sydney (so as a member of SydneyUni), but is automatically registered here as a member of ULB because he worked at ULB almost ten years ago.Ben Thornber is also a member of the University of Sydney but the application does not save it for an unknown reason.
info:eu-repo/semantics/nonPublished
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Sharifzadeh, Shayan. "Design Optimization and Analysis of Long-Range Hydrogen-Fuelled Hypersonic Cruise Vehicles." Thesis, The University of Sydney, 2017. http://hdl.handle.net/2123/19127.
Повний текст джерелаАнотація:
Aviation industry is continuously growing especially for very long distance flights due to the globalisation of local economies around the world and the explosive economic growth in Asia. Reducing the time of intercontinental flights from 16-20 hours to 4 hours or less would therefore make the, already booming, ultra-long distance aviation sector even more attractive. To accomplish this drastic travel time reduction for civil transport, hypersonic cruise aircraft are considered as a potential cost-effective solution. Such vehicles should also be fuelled by liquid hydrogen, which is identified as the only viable propellant to achieve antipodal hypersonic flight with low environmental impact. Despite considerable research on hypersonic aircraft and hydrogen fuel, several major challenges should still be addressed before such airliner becomes reality. The current thesis is therefore motivated by the potential benefit of hydrogen-fuelled hypersonic cruise vehicles associated with their limited state-of-the-art. Hypersonic cruise aircraft require innovative structural configurations and thermal management solutions due to the extremely harsh flight environment, while the uncommon physical properties of liquid hydrogen, combined with high and long-term heat fluxes, introduce complex design and technological storage issues. Achieving hypersonic cruise vehicles is also complicated by the multidisciplinary nature of their design. In the scope of the present research, appropriate methodologies are developed to assess, design and optimize the thermo-structural model and the cryogenic fuel tanks of long-range hydrogen-fuelled hypersonic civil aircraft. Two notional vehicles, cruising at Mach 5 and Mach 8, are then investigated with the implemented methodologies. The design analysis of light yet highly insulated liquid hydrogen tanks for hypersonic cruise vehicles indicates an optimal gravimetric efficiency of 70-75% depending on insulation system, tank wall material, tank diameter, and flight profile. A combination of foam and load-bearing aerogel blanket leads to the lightest cryogenic tank for both the Mach 5 and the Mach 8 aircraft. If the aerogel blanket cannot be strengthened sufficiently so that it can bear the full load, then a combination of foam and fibrous insulation materials gives the best solution for both vehicles. The aero-thermal and structural design analysis of the Mach 5 cruiser shows that the lightest hot-structure is a titanium alloy construction made of honeycomb sandwich panels. This concept leads to a wing-body weight of 143.9 t, of which 36% accounts for the wing, 32% for the fuselage, and 32% for the cryogenic tanks. As expected, hypersonic thermal loads lead to important weight penalties (of more than 35 %). The design of the insulated cold structure, however, demonstrates that the long-term high-speed flight of the airliner requires a substantial thermal protection system, such that the best configuration (obtained by load-bearing aerogel blanket) leads to a titanium cold design of only 4% lighter than the hot structure. Using aluminium 7075 rather than titanium offers a further weight saving of about 2 %, resulting in a 135.4 t wing-body weight (with a contribution of 23 %, 25 %, 18%and 34%from the TPS, the wing, the fuselage, and the cryogenic tanks respectively). Given the design hypotheses, the difference in weight is not significant enough to make a decisive choice between hot and cold concepts. This requires the current methodologies to be further elaborated by relaxing the simplifications. Investigation of the thermal protection must be extended from one single point to different regions of the vehicle, and the TPS thickness and weight should be considered in the structural sizing of the cold design. More generally, the design process should be matured by including additional (static, dynamic and transient) loads, special structural concepts, multi-material configurations and other parameters such as cost and safety aspects.
44
Pentland, Wendy E. "Upper extremity function in long term paraplegia and implications for independence." Thesis, Curtin University, 1992. http://hdl.handle.net/20.500.11937/2435.
Повний текст джерелаАнотація:
The intent of this study was to describe the effects of long term paraplegia and wheelchair use on upper limb function. Bilateral upper extremity isokinetic and grip strength, pain, and active range of motion were compared in 52 men with paraplegia (mean age 44 years: mean duration of spinal cord injury (SCI) 17 years) and 52 age and activity-level matched able-bodied men. The impact of upper limb pain on activities of daily living (ADL) performance was examined in the paraplegic sample. Strength was not significantly different between the two samples except for bilateral shoulder flexion (able-bodied stronger) and bilateral elbow extension (paraplegia stronger). Strength changed similarly with age in the two groups. The effect of duration of SCI on strength, excluding age, was significant for grip strength only. Duration of paraplegia and activity-level were better predictors of strength than age in 9 of 14 muscle groups, whereas in the able-bodied, age was the best strength predictor. Limited bilateral shoulder internal rotation and non-dominant external rotation were associated with paraplegia. Upper limb pain in the past week was associated with paraplegia (shoulder p<.001; elbow p<.00l; wrist/hand p<.00l). Reported pain prevalences for the paraplegic sample were: shoulder 39%, elbow 31%, wrist/hand 40%. The paraplegic subjects' pain intensity ratings revealed them to be experiencing mild to moderate levels of upper limb pain. Shoulder pain was associated with duration of injury, exclusive of age (p<.05). Measurement of the impact of upper limb pain On 18 activities of daily living (ADL) tasks revealed pain to be experienced by the majority of subjects with paraplegia (mobility tasks 60%; self-care tasks 5 8 % ; general activities tasks 60%). However, only 23-35% had made changes in their routines, and 6-16% had sought assistance with ADL due to upper limb pain. When age was excluded, it appeared that duration of SCI was more associated with pain during ADL, but this was significant only for pain during self-care tasks. The tasks most reported to cause upper limb pain were work/school, sleep, wheelchair transfers, outdoor wheeling, and driving. These results suggest that preventative and management steps are required to ensure continued independence and quality of life in this group over time. The effect of duration of SCI suggests that limitations in upper limb function may be seen in this population at relatively young ages.
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Теліженко, Олександр Михайлович, Александр Михайлович Телиженко, and Oleksandr Mykhailovych Telizhenko. "Perfection of system of controlled trade emission by the certificates within the framework of realization long range transboundary air pollution." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/31282.
Повний текст джерелаАнотація:
In scientific works (G. Klaassen, M. Amman, S. Kruitwagen etc.), the condition of redistribution of emissions between sources (member-countries LRTAP), is submitted as system.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/31282
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Pentland, Wendy E. "Upper extremity function in long term paraplegia and implications for independence." Curtin University of Technology, School of Physiotherapy, 1992. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=15684.
Повний текст джерелаАнотація:
The intent of this study was to describe the effects of long term paraplegia and wheelchair use on upper limb function. Bilateral upper extremity isokinetic and grip strength, pain, and active range of motion were compared in 52 men with paraplegia (mean age 44 years: mean duration of spinal cord injury (SCI) 17 years) and 52 age and activity-level matched able-bodied men. The impact of upper limb pain on activities of daily living (ADL) performance was examined in the paraplegic sample. Strength was not significantly different between the two samples except for bilateral shoulder flexion (able-bodied stronger) and bilateral elbow extension (paraplegia stronger). Strength changed similarly with age in the two groups. The effect of duration of SCI on strength, excluding age, was significant for grip strength only. Duration of paraplegia and activity-level were better predictors of strength than age in 9 of 14 muscle groups, whereas in the able-bodied, age was the best strength predictor. Limited bilateral shoulder internal rotation and non-dominant external rotation were associated with paraplegia. Upper limb pain in the past week was associated with paraplegia (shoulder p<.001; elbow p<.00l; wrist/hand p<.00l). Reported pain prevalences for the paraplegic sample were: shoulder 39%, elbow 31%, wrist/hand 40%. The paraplegic subjects' pain intensity ratings revealed them to be experiencing mild to moderate levels of upper limb pain. Shoulder pain was associated with duration of injury, exclusive of age (p<.05). Measurement of the impact of upper limb pain On 18 activities of daily living (ADL) tasks revealed pain to be experienced by the majority of subjects with paraplegia (mobility tasks 60%; self-care tasks 5 8 % ; general activities tasks 60%). However, only 23-35% had made changes in their routines, and 6-16% had sought assistance with ADL due to upper limb pain. ++When age was excluded, it appeared that duration of SCI was more associated with pain during ADL, but this was significant only for pain during self-care tasks. The tasks most reported to cause upper limb pain were work/school, sleep, wheelchair transfers, outdoor wheeling, and driving. These results suggest that preventative and management steps are required to ensure continued independence and quality of life in this group over time. The effect of duration of SCI suggests that limitations in upper limb function may be seen in this population at relatively young ages.
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Sun, Wen. "A study of interacting stochastic networks : large scale, long time behavior and fluctuations, with applications in communication networks and protein polymerization." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS075.
Повний текст джерелаАнотація:
Ce document est consacré aux analyses de grands réseaux stochastiques utilisés pour étudier des réseaux de communication et ainsi que certains phénomènes biologiques. La première partie se compose de trois modèles pour évaluer l’efficacité des algorithmes de duplication et de placement dans les grands systèmes distribués. Au chapitre 2, la dynamique du système est décrite l’aide de la mesure empirique associée à un processus de transient multidimensionnel. Une étude détaillée de ces processus est effectuée sur plusieurs échelles de temps rapides. Des principes de moyenne stochastique avec plusieurs échelles de temps sont étudiées. Aux chapitres 3 et 4, les interactions considérées peuvent avoir des tailles de saut illimitées et se produire dans un ensemble aléatoire fini de nœuds. Le processus de la mesure empirique associé n’ayant pas d’équations d’évolution simples, nous développons une analyse de champ moyen spécifique pour étudier ces systèmes. Le comportement en temps long des processus de diffusions non linéaires correspondants est aussi analysé. La deuxième partie présente deux modèles pour étudier la variabilité dans les modèles de polymérisation. Dans le chapitre 5, nous étudions les processus de polymérisation et de fragmentation avec l’hypothèse d’un noyau critique pour la taille des polymères. Notre résultat montre que ces modèles semblent donner une explication raisonnable de la transition de phase courte du phénomène de polymérisation, et surtout de la grande variabilité de l’instant de transition, qui ont été observés dans de nombreuses expériences. Au chapitre 6, nous proposons un théorème de limite centrale fonctionnelle dans le modèle de Becker-DöringThis PhD document is devoted to the analyses of large stochastic networks used to study mathematical models in communication networks and in biology. The first part consists of the analysis of three models used to evaluate the efficiency of duplication and placement algorithms in large distributed systems. These models are represented by large stochastic networks under different scaling regimes assumptions. In Chapter 2, the dynamic of the system can be described with the empirical measure associated to a multi-dimensional transient Markov process. We provide a detailed study of these processes on several fast time scales. Stochastic averaging principles with multiple time scales are investigated in particular. In Chapter 3 and Chapter 4, the interactions have unbounded jump sizes and occur within a limited random set of nodes. We develop a convenient mean field analysis in despite that the associated empirical measures do not have autonomous evolution equations. We also study the long time behavior of the corresponding limiting nonlinear jump diffusions. The second part analyzes two models used to study the variability in the polymerization phenomena occurring in a biological context. In Chapter 5, we investigate the polymerization and fragmentation processes with an assumption of critical nucleus size. A scaling analysis of these stochastic models show that the sharp phase transition and, especially the large variance, observed in the experiments can be explained by these models. In Chapter 6, we provide a functional central limit theorem in the classical (infinite dimensional) stochastic Becker-Döring model
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Gullipalli, Raashita, and Kiran Kumar Golla. "Arduino-Based Radio Technology System for Bird Protection : Wind Farm Application Approach." Thesis, Blekinge Tekniska Högskola, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-20056.
Повний текст джерела
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Kaiser, Vojtech. "The Wien Effect in Electric and Magnetic Coulomb systems - from Electrolytes to Spin Ice." Thesis, Lyon, École normale supérieure, 2014. http://www.theses.fr/2014ENSL0942/document.
Повний текст джерелаАнотація:
Les gaz ou fluides de Coulomb sont composés de particules chargées couplées entre elles par interaction coulombienne à longue portée. De part la nature de ces interactions, la physique du gaz de Coulomb est très riche, comme par exemple dans des électrolytes plus ou moins complexes, mais aussi à travers l'émergence de monopôles magnétiques dans la glace de spin. Dans cette thèse nous nous intéressons au comportement hors d'équilibre des gaz de Coulomb et de la glace de spin. Au centre de cette étude se trouve le deuxième effet de Wien, qui est une croissance linéaire de la conductivité en fonction du champ électrique appliqué à un électrolyte faible. Ce phénomène est une conséquence directe de l'interaction coulombienne qui pousse les charges à se lier par paires ; le champ électrique va alors aider à dissocier ces paires et créer des charges mobiles qui amplifient la conductivité. Le deuxième effet de Wien est un processus hors-équilibre non-linéaire, remarquablement décrit par la théorie de Onsager. Nos simulations sur réseau permettent de découvrir le rôle de l'environnement ionique qui agit contre le deuxième effet de Wien, ainsi que de caractériser la mobilité du système et sa dépendance en fonction du champ externe. Les simulations nous ont aussi donné accès aux corrélations de charges qui décrivent le processus microscopique à la base de l'effet Wien. Enfin, nous regardons plus précisément le gaz émergent de monopôles dans la glace de spin, aussi appelé « magnétolyte », capable de décrire de manière remarquable les propriétés magnétiques de glace de spin. Nous décrivons la dynamique complète hors-équilibre de cette magnétolyte soumise à une forçage périodique ou une trempe dans un champ magnétique en incluant à la fois le deuxième effet de Wien et la réponse du réseau de spins qui est à la base de l'émergence des monopôles magnétiques. Tout au long, nous utilisons une simple extension des simulations de gaz de Coulomb sur réseau pour préciser nos prédictions. Il est très rare de trouver une théorie analytique du comportement hors-équilibre d'un système hautement frustré au-delà de la réponse linéaireA Coulomb gas or fluid comprises charged particles that interact via the Coulomb interaction. Examples of a Coulombic systems include simple and complex electrolytes together with magnetic monopoles in spin ice. The long-range nature of the Coulomb interaction leads to a rich array of phenomena.This thesis is devoted to the study of the non-equilibrium behaviour of lattice based Coulomb gases and of the quasi-particle excitations in the materials known as spin ice which constitute a Coulomb gas of magnetic charges. At the centre of this study lies the second Wien effect which describes the linear increase in conductivity when an electric field is applied to a weak electrolyte. The conductivity increases due to the generation of additional mobile charges via a field-enhanced dissociation from Coulombically bound pairs.The seminal theory of Onsager gave a detailed analysis of the Wien effect. We use numerical simulations not only to confirm its validity in a lattice Coulomb gas for the first time but mainly to study its extensions due to the role of the ionic atmosphere and field-dependent mobility. The simulations also allow us to observe the microscopic correlations underlying the Wien effect.Finally, we look more closely at the emergent gas of monopoles in spin ice—the magnetolyte. The magnetic behaviour of spin ice reflects the properties of the Coulomb gas contained within. We verify the presence of the Wien effect in model spin ice and in the process predict the non-linear response when exposed to a periodic driving field, or to a field quench using Wien effect theory. We use a straightforward extension of the lattice Coulomb gas simulations to refine our predictions. It is a highly unusual result to find an analytic theory for the non-equilibrium behaviour of a highly frustrated system beyond linear response
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Masella, Guido. "Exotic quantum phenomena in cold atomic gases : numerical approaches." Thesis, Strasbourg, 2019. http://www.theses.fr/2019STRAF061.
Повний текст джерелаАнотація:
L'objectif principal de cette thèse est l'étude des propriétés à basse énergie et température de systèmes fortement corrélés de bosons interagissant via des potentiels à portée longue et étendue, et pertinentes pour la réalisation expérimentale avec des gaz atomiques froids. Cette étude est réalisée à l'aide d'une combinaison de techniques numériques, comme le Path Integral Montecarlo et de techniques analytiques. Le principal résultat de mon travail est la démonstration de l’existence d’une phase supersolide à bandes et d’une rare transition entre différents supersolides dans un modèle à interaction finie de bosons de coer dur sur un réseau carré. J'étudie également les scénarios hors d'équilibre de tels modèles via des quenches de température simulées. Enfin, j'étudie comment la restauration de l'extensibilité énergétique dans des systèmes en interaction à longue portée peut avoir une incidence profonde sur les propriétés de basse énergie dans la limite thermodynamiqueThe central aim of this thesis is the study of the low-energy and low-temperature properties of strongly correlated systems of bosonic particles interacting via finite- and long-range potentials, and relevant to experimental realization with cold atomic gases. This study is carried out with a combination of state-of-the-art numerical techniques such as Path Integral Monte Carlo and analytical techniques. The main result of my work is the demonstration of the existence of a stripe supersolid phase and of a rare transition between isotropic and anisotropic supersolids in a finite-range interacting model of hard-bosons on a square lattice. I also investigate the out-of-equilibrium scenarios of such models via simulated temperature quenches. Finally, I investigate how restoring energy extensivity in long-range interacting systems can have a profound incidence on the low-energy properties in the thermodynamic limit