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Dissertations / Theses on the topic 'Fluctuation'

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Published: 4 June 2021

Last updated: 25 May 2024

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Ploetz, Elizabeth Anne. "Fluctuation solution theory." Diss., Kansas State University, 2014. http://hdl.handle.net/2097/18390.

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Doctor of Philosophy
Department of Chemistry
Paul E. Smith
The Kirkwood-Buff (KB) theory of solutions, published in 1951, established a route from integrals over radial (pair) distribution functions (RDFs) in the grand canonical ensemble to a set of thermodynamic quantities in an equivalent closed ensemble. These “KB integrals” (KBIs) can also be expressed in terms of the particle-particle (i.e., concentration or density) fluctuations within grand canonical ensemble regions. Contributions by Ben-Naim in 1977 provided the means to obtain the KBIs if one already knew the set of thermodynamic quantities for the mixture of interest; that is, he provided the inversion procedure. Thus, KB theory provides a two-way bridge between local (microscopic) and global (bulk/thermodynamic) properties. Due to its lack of approximations, its wide ranging applicability, and the absence of a competitive theory for rigorously understanding liquid mixtures, it has been used to understand solution microheterogeneity, solute solubility, cosolvent effects on biomolecules, preferential solvation, etc. Here, after using KB theory to test the accuracy of pair potentials, we present and illustrate two extensions of the theory, resulting in a general Fluctuation Solution Theory (FST). First, we generalize KB theory to include two-way relationships between the grand canonical ensemble’s particle-energy and energy-energy fluctuations and additional thermodynamic quantities. This extension allows for non-isothermal conditions to be considered, unlike traditional KB theory. We illustrate these new relationships using analyses of experimental data and molecular dynamics (MD) simulations for pure liquids and binary mixtures. Furthermore, we use it to obtain conformation-specific infinitely dilute partial molar volumes and compressibilities for proteins (other properties will follow) from MD simulations and compare the method to a non-FST method for obtaining the same properties. The second extension of KB theory involves moving beyond doublet particle fluctuations to additionally consider triplet and quadruplet particle fluctuations, which are related to derivatives of the thermodynamic properties involved in regular KB theory. We present these higher order fluctuations obtained from experiment and simulation for pure liquids and binary mixtures. Using the newfound experimental third and fourth cumulants of the distribution of particles in solution, which can be extracted from bulk thermodynamic data using this extension, we also probe particle distributions’ non-Gaussian nature.

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Garrity, Patrick Louis. "Nanoscale Thermal Fluctuation Spectroscopy." ScholarWorks@UNO, 2009. http://scholarworks.uno.edu/td/912.

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The utilization of thermal fluctuations or Johnson/Nyquist noise as a spectroscopic method to determine transport properties in conductors or semiconductors is developed in this paper. The autocorrelation function is obtained from power spectral density measurements thus enabling electronic transport property calculation through the Green-Kubo formalism. This experimental approach is distinct from traditional numerical methods such as molecular dynamics simulations, which have been used to extract the autocorrelation function and directly related physics only. This work reports multi-transport property measurements consisting of the electronic relaxation time, resistivity, mobility, diffusion coefficient, electronic contribution to thermal conductivity and Lorenz number from experimental data. Double validation of the experiment was accomplished through the use of a standard reference material and a standard measurement method, i.e. four-probe collinear resistivity technique. The advantages to this new experimental technique include the elimination of any required thermal or potential gradients, multi-transport property measurements within one experiment, very low error and the ability to apply controlled boundary conditions while gathering data. This research has experimentally assessed the gas pressure and flow effects of helium and argon on 30 nm Au and Cu thin films. The results show a reduction in Au and Cu electronic thermal conductivity and electrical resistivity when subjected to helium and argon pressure and flow. The perturbed electronic transport coefficients, attributed to increased electron scattering at the surface, were so dominant that further data was collected through straight-forward resistance measurements. The resistance data confirmed the thermal noise measurements thus lending considerable evidence to the presence of thin film surface scattering due to elastic and inelastic gas particle scattering effects with the electron ensemble.

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Ridgway, Douglas Thacher. "Fluctuation-controlled front propagation /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC IP addresses, 1997. http://wwwlib.umi.com/cr/ucsd/fullcit?p9820864.

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Sibanic, Sofia. "Mains Frequency Fluctuation Metering." Thesis, Sibanic, Sofia (2013) Mains Frequency Fluctuation Metering. Other thesis, Murdoch University, 2013. https://researchrepository.murdoch.edu.au/id/eprint/21903/.

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Detecting the frequency of the mains supply is a crucial component of maintaining the grid frequency at its nominal level. Most frequency counters enable the user to monitor frequencies but monitoring frequency variations at a high resolution is often expensive. Electronic systems that measure frequency also have to generate a local time base to calculate the frequency upon. All time bases suffer from the effect of frequency jitter, which makes the timing source deviate from the nominal second by a quantified amount. Modern systems have improved drastically and have relatively insignificant jitter for most timing applications, but high-precision applications require a quantification of this source of timing error. The purpose of this thesis is to document the background, implementation, testing, results and identified future improvements for a frequency meter that can record minor fluctuations of the grid frequency. By achieving this objective, the grid supply and demand data can be logged and used for several applications, such as network forecasting or maintaining nominal grid frequency. An extensive research period was required to determine key design facets pertaining to the frequency meter. Key identified tasks included choosing a timing source, finding a suitable software development platform and associated hardware, developing a graphical software implementation that displays real-time frequency fluctuations, contingency alarming for nominal frequency deviation events, communications design between the frequency meter and the PC, quantifying clock precision and evaluating the performance of the final frequency meter. A GPS time source was chosen to provide an accurate source of 1 second pulses. An Arduino Due microcontroller used a KX-7 quartz crystal oscillator to maintain its time base and the accuracy of the KX-7’s time base was analysed against the Trimble Copernicus II and GlobalSat EM406-A GPS receivers’ time base. When analysed relative to the GPS receivers’ accurate time base, the KX-7 maintained a low time base variation, well within it’s data sheet specifications. The Arduino Due microcontroller was programmed and provided relevant frequency data to a LabVIEW PC terminal, which allowed frequency visualisation, data storage, grid frequency contingency detection, recovery time logging, GPS initialisation data and cross-platform communication protocols. Frequency data was logged on the frequency meter and was able to provide a microHertz resolution. The primary limitation of the design was low-level noise on the mains supply line as this affected the designed electronics when logging frequency measurements below the milliHertz range. Multiple recommendations for future work have been identified and included in this report.

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Joubaud, Sylvain. "Fluctuations dans les systèmes hors équilibre." Lyon, École normale supérieure (sciences), 2008. http://www.theses.fr/2008ENSL0463.

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Les travaux décrits dans cette thèse apportent une contribution à la physique statistique des fluctuations de systèmes portés hors de leur état d'équilibre. Les résultats ont été obtenus sur deux systèmes expérimentaux. Le premier système est un oscillateur harmonique fluctuant sous l'effet de l'agitation thermique. Ce système est porté par un forçage externe dans deux types d'états hors d'équilibre : un état transitoire et un état stationnaire. Nous mesurons dans ce système modèle les fluctuation du travail injecté, de la chaleur dissipée et de la production d'entropie totale. L'étude statistique de ces fluctuations est réalisée dans le contexte des Théorèmes de Fluctuation. Par comparaison des résultats expérimentaux et d'un modèle théorique simple, nous donnons une interprétation physique des différents résultats obtenus. La seconde partie est consacrée à l'etude de la transition de Fréedericksz dans les cristaux liquides. Cette transition est équivalente à une transition de phase du deuxième ordre. Nous proposons une méthode de mesure du paramètre d'ordre de la transition ayant une excellente résolution jusqu'à des fréquences de l'ordre du millihertz. Nous étudions la statistique des fluctuations d'équilibre lorsque le paramètre de contrôle est proche dela valeur critique. La distribution est comparée avec la distribution Gumbel Généralisée et le paramètere de ce modèle est interprété comme un nombre de degrés de liberté effectifs. Ce système est finalement étudié hors d'équilibre lors d'une trempe au point critique accompagné d'un phénomène de vieillissement
The results reported in this thesis contribute to the understanding of the fluctuations of out of equilibrium systems. They havve been obtained in two experimental systems. The first system is a harmonic oscillator fluctuating because of the thermal noise. This system is driven out of equilibrium by an external forcing. Two case are sudied : the transient state and the steady state. We measure in this model system work fluctuations, heat fluctuations and total entropy fluctuations. These fluctuationsare studied within the context of Fluctuation Theorem. The results are interpreted by comparing the experimental results with a simple theoretical model. The second part is dedicated to the study of the Fréedericks transition in a nematic liquid crystal which is a second order phase transition. Our experimental setup for the measurment of the order parameter has a very good resolution at low frequency; of the order of millihertz. We study the statiticsof the equillibrium fluctuations when the control parameter is close to its critical value. The distribution is copared to a Generalized Gumbel distribution and the parmeter of this modeling is related to the effective number of degrees of freedom. We finally study this system out of equilibrium. We show that after a quench at the critical point the system present aging properties. Preliminary results are presented

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Andersson, Andreas. "Phase fluctuation phenomena in superconductors." Doctoral thesis, KTH, Statistisk fysik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-95464.

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Wood, Andrew James. "Fluctuation effects at filling transitions." Thesis, Imperial College London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269975.

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Li, Shengcai. "Cavitation associated low-frequency fluctuation." Thesis, University of Warwick, 1990. http://wrap.warwick.ac.uk/108599/.

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This self-guided thesis presents the research results of the Cavitation Associated Low-frequency Fluctuation, i. e. one part of the long-term research project on Statistical Characteristics of Cavitation Bubble Collapse Pulses. Associated Low-frequency Fluctuations and Flow Noise which was initiated and carried out by the author in USA. China and UK successively over last 9 years. The background and the objectives of the long-term project is introduced in the thesis through a broad review of the development of the cavitation research in the fields relevant to the project. Then, the observed phenomenon of Cavitation Associated Low-frequency Fluctuation in the venturi cavitating flow of the University of Michigan ( USA ) is explained in detail. A one-dimensional linear physical model based on the theorem of the interaction between the cavitation cloud of the homogeneous liquid-vapour/gas mixture and the surrounding liquid portion in the flow system is proposed to describe the mechanism of the phenomenon. The appearance of this low-frequency fluctuation is an association nature of the cavitating flow, which could be regarded as an alternatively indirect indicator of cavitation inception especially in such sort of cavitating flow systems. When the natural frequencies for both the cavitation cloud and the surrounding liquid portion coincide, the low- frequency pressure fluctuation component reaches its maximum, which is defined as Cavitation Resonance. A numerical verification of the frequency response characteristics, using the hydraulic impedance approach, of this venturi system is presented as well. The knowledge of the cavitation associated low-frequency fluctuation acquired from the study of the venturi cavitating flow has been used to analyze the phenomenon of the pressure fluctuations associated with the cavitating flows in the hydraulic machinery systems such as the HL-160-25 ( Francis ) Hydraulic Turbine System (draft-tube cavitating flow). The results are also briefly presented.

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Yao, Jianfeng. "Estimation et fluctuations de fonctionnelles de grandes matrices aléatoires." Thesis, Paris, ENST, 2013. http://www.theses.fr/2013ENST0080/document.

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L’objectif principal de la thèse est : l’étude des fluctuations de fonctionnelles du spectre de grandes matrices aléatoires, la construction d’estimateurs consistants et l’étude de leurs performances, dans la situation où la dimension des observations est du même ordre que le nombre des observations disponibles. Il y aura deux grandes parties dans cette thèse. La première concerne la contribution méthodologique. Nous ferons l’étude des fluctuations pour les statistiques linéaires des valeurs propres du modèle ’information-plus-bruit’ pour des fonctionnelles analytiques, et étendrons ces résultats au cas des fonctionnelles non analytiques. Le procédé d’extension est fondé sur des méthodes d’interpolation avec des quantités gaussiennes. Ce procédé est appliqué aux grandes matrices de covariance empirique. L’autre grande partie sera consacrée à l’estimation des valeurs propres de la vraie covariance à partir d’une matrice de covariance empirique en grande dimension et l’étude de son comportement. Nous proposons un nouvel estimateur consistant et étudions ces fluctuations. En communications sans fil, cette procédure permet à un réseau secondaire d’établir la présence de ressources spectrales disponibles
The principal objective of this thesis is : the study of the fluctuations of functionals of spectrum for large random matrices, the construction of consistent estimators and the study of their performances, in the situation where the dimension of observations is with the same order as the number of the available observations. There will be two parts in the report : the methodological contribution and the estimation in large-dimensional data. As to the methodological contribution, we will study the fluctuations for spectral linear statistics of the model ’information-plus-noise’ for analytic functionals, and the extension for non-analytic functionals. The extension is based on the interpolation between random variables and Gaussian terms. This method can be applied to empirical covariance matrices. Another part consists in the estimation of the eigenvalues of the real covariance from the empirical covariance for high dimensional data and the study of its performance. We propose a new consistent estimator and the fluctuation of the estimator will be studied . In wireless communications, this procedure permits a secondary network to ensure the presence of the available spectral resources

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Stroh, RuÌˆediger Joachim. "Fluctuation phenomena in mesoscopic silicon devices." Thesis, University of Cambridge, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358804.

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Côté, Alain C. "Density fluctuation measurements with laser scattering." Thesis, University of Oxford, 1989. http://ora.ox.ac.uk/objects/uuid:2580d8c1-32f7-40c6-afe1-14ebde9641f3.

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-2 power law. The average phase velocities are around 4.5 km/sec and are slightly larger than the electron diamagnetic drift velocity. The waves are tentatively identified with the electron drift mode. Coherent signals due to long wavelength MHD modes are detected. Results from a Langmuir probe corroborate most of these data.

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Lord, Nathan Dale. "Fluctuation Timescales in Bacterial Gene Expression." Thesis, Harvard University, 2013. http://dissertations.umi.com/gsas.harvard:11261.

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The stochastic nature of intracellular chemistry guarantees that even genetically identical cells sharing an environment will differ in composition. The question of whether this chemical diversity translates into significant phenotypic individuality is tied to the relative timescales of the processes involved. In order for cells in a population to have distinct functional identities, they must maintain their states for an appreciable period of time. Quantification of these timescales requires accurate time-lapse measurements covering tens or even hundreds of generations, a technical hurdle that has left these questions largely underexplored. In this thesis I present three pieces of work that aim to provide a foundation for the study of fluctuation timescales in bacteria. In the first part, I describe modifications to a recently developed microfluidic platform for continuous culture of cells under constant conditions. These revised devices enable the high-throughput, long-term measurement of gene expression dynamics while eliminating several confounding experimental factors that interfere with timescale measurements. In the second part, I employ one of these devices to survey fluctuation timescales in ~50 reporters for Eshcerichia coli gene expression. Under rich conditions, all reporters exhibited nearly identical, rapid fluctuation dynamics that were captured by a simple model of gene expression. In contrast, under poor nutritional conditions gene expression states became correlated over several cell divisions. However, accounting for instantaneous growth rate fluctuations eliminated these slow timescales, revealing an exceedingly simple behavior. In the third part, I describe our work to dissect the stochastic transition between the solitary motile state and sessile multicellular state in exponentially growing Bacillus subtilis

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Rodriguez-Wong, Alejandro. "Fluctuation-induced interactions and nonlinear nanophotonics." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/62653.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2010.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 293-329).
We present theoretical and numerical methods for studying Casimir forces and nonlinear frequency conversion in nanophotonic media consisting of arbitrary geometries and materials. The first section of the thesis focuses on the study of various geometry-enabled resonant effects leading to strong nonlinear interactions. The starting point of this work is a coupled-mode theory framework for modeling a wide range of resonant nonlinear frequency-conversion processes in general geometries, ameliorating the need for repeated and expensive finite-difference time-domain simulations. We examine the predictions of the theory for two particular nonlinear processes: harmonic generation and difference-frequency generation. Our results demonstrate strong enhancement of nonlinear interactions at a "critical" input power leading to 100% frequency conversion, among many other interesting dynamical effects. Using a quantum-mechanical description of light, based on cavity quantum electrodynamics, similar enhancement effects are demonstrated at the single-photon level, leading to the possibility of achieving all-optical switching of a single signal photon by a single gating photon in a waveguide-cavity geometry consisting of pumped four-level atoms embedded in a cavity. Finally, we describe how one may tailor the geometry of certain materials to enhance their nonlinear susceptibilities by exploiting a consequence of the Purcell effect. The second section of the thesis, the main contribution of this work, presents a new formulation for studying Casimir forces in arbitrary geometries and materials that directly exploits efficient and well-developed techniques in computational electromagnetism. To begin with, we present the step-by-step conceptual development of our computational method, based on a well-known stress tensor formalism for computing Casimir forces. A proof-of- concept finite-difference frequency-domain implementation of the stress-tensor method is described and checked against known results in simple geometries. Building on this work, we then describe the basic theoretical ingredients of a new technique for determining Casimir forces via antenna measurements in tabletop experiments. This technique is based on a (derived) correspondence between the complex-frequency deformation of the Casimir frequency-integrand for any given geometry and the real-frequency classical electromagnetic response of the same geometry, but with dissipation added everywhere. This correspondence forms the starting point of a numerical Casimir solver based on the finite-difference time-domain method, which we describe and then implement via an off-the-shelf time-domain solver, requiring no modifications. These numerical methods are then used to explore a wide range of geometries and materials, of various levels of complexity: First, a four-body piston-like geometry consisting of two cylinders next to adjacent walls, which exhibits a non-monotonic lateral Casimir force (explained via ray optics and the method of images); Second, a zipper-like, glide-symmetric structure that leads to a net repulsive force arising from a competition between attractive interactions. Finally, we examine a number of geometries consisting of fluid-separated objects and find a number of interesting results. These include: stable levitation and suspension of compact objects, dispersion-induced orientation transitions, and strong non-zero temperature Casimir effects.
by Alejandro Rodriguez-Wong.
Ph.D.

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Oelschläger, Marty. "Fluctuation-induced phenomena in nanophotonic systems." Doctoral thesis, Humboldt-Universität zu Berlin, 2020. http://dx.doi.org/10.18452/21484.

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Die vorliegende Arbeit befasst sich mit dem Thema der Nichtgleichgewichts-Dispersionskräfte. Der Fokus liegt auf der kontroversen Casimir- bzw. Quantenreibung. Sie tritt auf, wenn sich zwei elektrisch neutrale Körper relativ zueinander bewegen. Vermittelt wird diese kontaktlose Reibungskraft über fluktuierende elektromagnetische (Quanten-) Felder und ist somit der Kategorie der fluktuationsinduzierten Phänome zuzuordnen, deren bekannte Beispiele die Van-der-Waals-Kraft und der Casimir-Effekt sind. Im Speziellen wurde die Situation eines mikroskopischen Objektes, welches sich mit einer festgelegten Geschwindigkeit und Höhe über eine makroskopische und flache Oberfläche beweget, untersucht. Um einen Zugang in das Themenfeld zu erlangen, wird eine kurze Einleitung in die Theorie der linearen Antwort und der Dynamik offener Systeme gegeben. Des Weiteren, werden unterschiedliche Modelle zur Beschreibung des mikroskopischen Objektes eingeführt und verschiedene Konfigurationen und Modelle bezüglich der makroskopischen Oberfläche berücksichtigt. Neben einem exakten, wenn auch komplexen, Integralausdruck werden diverse asymptotische Ausdrücke für verschiedene relevante Grenzfälle der kontaktlosen Reibung hergeleitet. Darüber hinaus, um die Asymptoten mit der exakten Lösung vergleichen zu können, wurde eine numerisch Auswertungsroutine des exakten Ausdrucks entwickelt und implementiert. Durch die Nutzung einer vollen Nichtgleichgewichtbeschreibung und das Einbeziehen sowohl der Rückwirkung des elektromagnetischen Feldes auf die Dynamik des mikroskopischen Objektes, als auch dessen Rotationsfreiheitsgrade, werden bestehende theoretische Beschreibungen erweitert. Abschließend wird ein Ausblick auf experimentelle Messungen der kontaktlosen Reibung gegeben.
The present thesis addresses the topic of nonequilibrium dispersion forces. The focus lies on the controversial Casimir or quantum friction, which occurs when two electrically neutral bodies move at a relative velocity with respect to each other. The noncontact friction force is mediated by the fluctuations of the (quantum) electromagnetic field and therefore belongs to the category of fluctuation-induced phenomena, whose prominent examples are the van der Waals force and the Casimir effect. Especially, the setup of a microscopic object moving at a fixed velocity and height above a flat macroscopic surface is investigated. To access this topic, a brief introduction into linear response and open system dynamics is given. Moreover, different models for the description of the microscopic object are introduced and various setups and models of the flat macroscopic surface are considered. Besides an exact but rather involved integral expression, several asymptotic expressions of the noncontact friction for different relevant limits are derived. Furthermore, in order to compare the asymptotic with the exact expression, a numerical approach for its evaluation was developed and implemented. Using a full nonequilibrium approach, which includes the backaction of the electromagnetic field onto the microscopic object’s dynamics, as well as its rotational degrees, existing theoretical descriptions are extended. Eventually, an outlook towards experimental measurements of the noncontact friction is given.

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Song, Junliang. "Fluctuation driven phenomena in spinor Bose gas." Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/23709.

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In this thesis, we have investigated several fluctuation-driven phenomena in ultracold spinor Bose gases. In Bose-Einstein condensates of hyperfine spin-two (F=2) atoms, it is shown that zero-point quantum fluctuations completely lift the accidental continuous degeneracy in quantum spin nematic phases predicted by mean field analysis, and these fluctuations select out two distinct spin nematic states with higher symmetries. It is further shown that fluctuations can drive a novel type of coherent spin dynamics which is very sensitive to the variation of quantum fluctuations controlled by magnetic fields or potential depths in optical lattices. These results have indicated fundamental limitations of precision measurements based on mean field theories. In addition, fluctuation-driven coherent spin dynamics studied here is a promising tool to probe correlated fluctuations in many body systems. In another system -- a two-dimension superfluid of spin-one (F=1) Na²³ atoms -- we have investigated spin correlations associated with half quantum vortices. It is shown that when cold atoms become superfluid below a critical temperature a unique nonlocal topological order emerges simultaneously due to fluctuations in low dimensional systems. Our simulation have indicated that there exists a nonlocal softened pi-spin disclination structure associated with a half-quantum vortex although spin correlations are short ranged. We have also estimated fluctuation-dependent critical frequencies for half-quantum vortex nucleation in rotating optical traps. These results indicate that the strongly fluctuating ultracold spinor system is a promising candidate for studying topological orders that are the focus of many other fields.

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Tsuji, Yoshiyuki, and Takashi Ishihara. "Similarity scaling of pressure fluctuation in turbulence." The American Physical Society, 2003. http://hdl.handle.net/2237/7143.

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West, Ryan Matthew. "Work function fluctuation analysis of polyaniline films." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/47586.

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In this thesis, the development of a novel experimental technique for measuring the spontaneous, stochastic work function (WF) fluctuations of conducting polymer films, at equilibrium, is discussed. Polyaniline (PANI) is studied as a representative conducting polymer. This technique utilizes an insulated-gate field-effect transistor (IGFET) with PANI gate electrode (PANI-IGFET). The fluctuations of PANI WF are transduced into measurable drain current fluctuations of the device. By analyzing these fluctuations while systematically controlling the temperature, electric field and doping level, a model of WF fluctuations in PANI films is developed. These experiments suggest that the source of WF fluctuations is the hopping of charge carriers, or trapping/detrapping of charge carriers, around the Fermi level of the PANI film at the PANI-insulator interface. This process is thermally activated with a field and doping dependent activation energy in the range of 0.1 to 0.5 eV. Thus, this new technique provides detailed information about charge-carrier dynamics in the space-charge region of the PANI film, at equilibrium. These results have important implications for organic electronics and furthering fundamental understanding of the relationship between doping, disorder and work function in organic semiconductors.

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Wilkin, Samantha Louise. "Magnetic structures produced by the fluctuation dynamo." Thesis, University of Newcastle Upon Tyne, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.435639.

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Windridge, David. "A fluctuation analysis for optical cluster galaxies." Thesis, University of Bristol, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302173.

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Faghfoor, M. Mohammad (Faghfoor Maghrebi). "Fluctuation-induced phenomena in non-equilibrium systems." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/83826.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2013.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 128-134).
In this thesis, we investigate the implications of fluctuations in systems away, possibly even far, from equilibrium due to their motion either in or out of thermal equilibrium. This subject encompasses several topics in physics including the dynamical Casimir effect in the presence of moving boundaries, and non-contact friction between objects in relative motion. In both cases, photons are created due to the coupling of the motion and zero-point fluctuations in the vacuum, resulting in dissipation and radiative loss. We introduce a general formalism, equally applicable to lossy and ideal objects, to compute the quantum radiation and dissipation effects solely in terms of the classical scattering matrices. We obtain trace formulas which are general and independent of any approximation scheme where numerous examples, many novel, are discussed in great detail. Specifically, we give an exact treatment of quantum fluctuations in the context of a neutral rotating object, and show that it spontaneously emits photons and drags objects nearby, and compute the associated photon statistics and entropy generation. In the context of non-contact friction, we find a quantum analog of the classical Cherenkov effect for two neutral plates in relative motion, purely due to quantum fluctuations. We present a number of arguments and exact proofs, including a method introduced in the context of quantum field theory in curved space, as well as the scattering approach, to show that a friction force between two plates appears at a threshold velocity set by the speed of light in their medium.
by Mohammad F. Maghrebi.
Ph.D.

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Zeileis, Achim, and Kurt Hornik. "Generalized M-Fluctuation Tests for Parameter Instability." SFB Adaptive Information Systems and Modelling in Economics and Management Science, WU Vienna University of Economics and Business, 2003. http://epub.wu.ac.at/716/1/document.pdf.

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A general class of fluctuation tests for parameter instability in an M-estimation framework is suggested. The tests are based on partial sum processes of M-estimation scores for which functional central limit theorems are derived under the null hypothesis of parameter stability and local alternatives. Special emphasis is given to parameter instability in (generalized) linear regression models and it is shown that the introduced M-fluctuation tests contain a large number of parameter instability or structural change tests known from the statistics and econometrics literature. The usefulness of the procedures is illustrated using artificial data and data for the German M1 money demand, historical demographic time series from Großarl, Austria, and youth homicides in Boston.
Series: Report Series SFB "Adaptive Information Systems and Modelling in Economics and Management Science"

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Lai, Chaoqun. "Essays on Investment Fluctuation and Market Volatility." DigitalCommons@USU, 2008. https://digitalcommons.usu.edu/etd/200.

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This dissertation includes two different groups of objects in macroeconomics and financial economics. In macroeconomics, the aggregate investment fluctuation and its relation to an individual firm's behavior have been extensively studied for the past three decades. Most studies on the interdependence behavior of firms' investment focus on the key issue of separating a firm's reaction to others' behavior from reaction to common shocks. However, few researchers have addressed the issue of isolating this endogenous effect from a statistical and econometrical approach. The first essay starts with a comprehensive review of the investment fluctuation and firms' interdependence behavior, followed by an econometric model of lumpy investments and an analysis of the binary choice behavior of firms'investments. The last part of the first essay investigates the unique characteristics of the Italian economy and discusses the economic policy implications of our research findings. We ask a similar question in the field of financial economics: Where does stock market volatility come from? The literature on the sources of such volatility is abundant. As a result of the availability of high-frequency financial data, attention has been increasingly directed at the modeling of intraday volatility of asset prices and returns. However, no empirical research of intraday volatility analysis has been applied at both a single stock level and industry level in the food industry. The second essay is aimed at filling this gap by modeling and testing intraday volatility of asset prices and returns. It starts with a modified High Frequency Multiplicative Components GARCH (Generalized Autoregressive Conditional Heteroscedasticity) model, which breaks daily volatility into three parts: daily volatility, deterministic intraday volatility, and stochastic intraday volatility. Then we apply this econometric model to a single firm as well as the whole food industry using the Trade and Quote Data and Center for Research in Security Prices data. This study finds that there is little connection between the intraday return and overnight return. There exists, however, strong evidence that the food recall announcements have negative impacts on asset returns of the associated publicly traded firms.

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Peng, Di. "Vortex Dynamics and Induced Pressure/Load Fluctuations During Blade-Vortex Interactions." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1408967632.

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Bellon, Ludovic. "Vieillissement des systèmes vitreux et rapport fluctuation-dissipation." Phd thesis, Ecole normale supérieure de lyon - ENS LYON, 2001. http://tel.archives-ouvertes.fr/tel-00003649.

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Ce travail propose une étude expérimentale au niveau fondamental du vieillissement des matériaux vitreux, en vue de valider les approches théoriques récentes sur le sujet. Dans un premier chapitre, nous introduisons ces nouveaux concepts : basés sur l'analogie verre de spin - verre structuraux, ils définissent la température effective Teff de ces systèmes faiblement mais durablement hors d'équilibre. Cette observable se mesure via le rapport fluctuation dissipation d'un tel système.

Le second chapitre est consacré à l'étude de l'effet rajeunissement-mémoire dans un polymère, le poly(methyl methacrylate) (PMMA). En s'inspirant d'expériences sur les verres de spins, nous démontrons une analogie de comportement forte sur des effets fins entre ces systèmes très différents. Une interprétation théorique en terme de paysage d'énergie hiérarchique permet de rendre compte de ces propriétés communes. Cette similitude fait du PMMA un bon candidat pour une étude du rapport fluctuation dissipation, introduite dans un troisième chapitre. Notre approche du problème, basée sur la mesure des propriétés électriques, est soigneusement analysée pour déterminer précisément les barres d'erreurs. Nous démontrons ainsi la nécessité d'améliorer le rapport signal sur bruit de notre expérience avant de tirer des conclusions.

Dans les deux derniers chapitres, nous étudions un verre colloïdal : la Laponite. La mesure de Teff à l'aide des propriétés électriques de ce système, en suivant le protocole du troisième chapitre, met cette fois en évidence une nette violation du théorème fluctuation dissipation, en accord avec les théories récentes sur le vieillissement. Pour tester le caractère intrinsèque de cette température effective, nous en proposons finalement une seconde détermination à l'aide des propriétés rhéologiques du matériau. Un rhéomètre ultra-sensible est ainsi conçu, et les résultats préliminaires de cette expérience sont présentés.

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Buisson, Lionel. "Intermittence pendant le vieillissement et relation fluctuation dissipation." Phd thesis, Ecole normale supérieure de lyon - ENS LYON, 2003. http://tel.archives-ouvertes.fr/tel-00005035.

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Une étude expérimentale du vieillissement des matériaux vitreux,
basée sur l'analogie entre verres de spin et verres structuraux, a
été réalisée en introduisant une température effective Teff
pour ces systèmes faiblement hors équilibre. Cette nouvelle
observable se mesure via le rapport fluctuation dissipation.

La mesure de Teff sur les propriétés diélectriques d'un verre
polymérique (polycarbonate) après une trempe sous la température
de transition vitreuse montre que le théorème fluctuation
dissipation est fortement violé. L'amplitude et la persistance
dans le temps de cette violation sont des fonctions décroissantes
de la fréquence. Autour de 1 Hz, elle persiste plusieurs heures.
L'origine de la violation semble être due à une dynamique
fortement intermittente caractérisée par de grandes fluctuations.
Cette intermittence semble dépendre de la vitesse de trempe et de
la température d'arrêt. Une interprétation théorique basée sur le
modèle en piège permet de rendre compte de cette dynamique.

Un comportement intermittent très similaire a été observé pour un
verre colloïdal (Laponite) pendant la transition de l'état liquide
à l'état solide alors qu'aucune violation ou intermittence n'ont
été observées après une trempe lente réalisée sur un autre verre
polymérique, le poly(méthyl méthacrylate) (PMMA).

Nous présentons également une mesure mécanique préliminaire de la
relation fluctuation dissipation sur une tige de polycarbonate à
l'aide d'un interféromètre de Nomarski à deux bras.

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Hoeller, Matthias. "Advanced Fluorescence Fluctuation Spectroscopy with Pulsed Interleaved Excitation." Diss., lmu, 2011. http://nbn-resolving.de/urn:nbn:de:bvb:19-128621.

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Kamikado, Kazuhiko. "Chiral phase transition in QCD with critical fluctuation." 京都大学 (Kyoto University), 2013. http://hdl.handle.net/2433/175113.

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Ito, Hiroaki. "Shape fluctuation and deformation of biological soft interfaces." 京都大学 (Kyoto University), 2016. http://hdl.handle.net/2433/215286.

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Stenqvist, Evita, and Jacob Lönnö. "Predicting Bitcoin price fluctuation with Twitter sentiment analysis." Thesis, KTH, Skolan för datavetenskap och kommunikation (CSC), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-209191.

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Programmatically deriving sentiment has been the topic of many a thesis: it’s application in analyzing 140 character sentences, to that of 400-word Hemingway sentences; the methods ranging from naive rule based checks, to deeply layered neural networks. Unsurprisingly, sentiment analysis has been used to gain useful insight across industries, most notably in digital marketing and financial analysis. An advancement seemingly more excitable to the mainstream, Bitcoin, has risen in number of Google searches by three-folds since the beginning of this year alone, not unlike it’s exchange rate. The decentralized cryptocurrency, arguably, by design, a pure free market commodity – and as such, public perception bears the weight in Bitcoins monetary valuation. This thesis looks toward these public perceptions, by analyzing 2.27 million Bitcoin-related tweets for sentiment fluctuations that could indicate a price change in the near future. This is done by a naive method of solely attributing rise or fall based on the severity of aggregated Twitter sentiment change over periods ranging between 5 minutes and 4 hours, and then shifting these predictions forward in time 1, 2, 3 or 4 time periods to indicate the corresponding BTC interval time. The prediction model evaluation showed that aggregating tweet sentiments over a 30 min period with 4 shifts forward, and a sentiment change threshold of 2.2%, yielded a 79% accuracy.
Ämnet sentiment analysis, att programmatiskt härleda underliggande känslor i text, ligger som grund för många avhandlingar: hur det tillämpas bäst på 140 teckens meningar såväl som på 400-ords meningar a’la Hemingway, metoderna sträcker sig ifrån naiva, regelbaserade, till neurala nätverk. Givetvis sträcker sig intresset för sentiment analys utanför forskningsvärlden för att ta fram insikter i en rad branscher, men framförallt i digital marknadsföring och financiell analys. Sedan början på året har den digitala valutan Bitcoin stigit trefaldigt i sökningar på Google, likt priset på valutan. Då Bitcoins decentraliserade design är helt transparant och oreglerad, verkar den under ideala marknadsekonomiska förutsättningar. På så vis regleras Bitcoins monetära värde av marknadens uppfattning av värdet. Denna avhandling tittar på hur offentliga uppfattningar påverkar Bitcoins pris. Genom att analysera 2,27 miljoner Bitcoin-relaterade tweets för sentiment ändringar, föutspåddes ändringar i Bitcoins pris under begränsade förhållningar. Priset förespåddes att gå upp eller ner beroende på graden av sentiment ändring under en tidsperiod, de testade tidsperioderna låg emellan 5 minuter till 4 timmar. Om en förutspånning görs för en tidsperiod, prövas den emot 1, 2, 3 och 4 skiftningar framåt i tiden för att ange förutspådd Bitcoin pris interval. Utvärderingen av förutspåningar visade att aggregerade tweet-sentiment över en 30-minutersperiod med 4 skift framåt och ett tröskelvärde för förändring av sentimentet på 2,2 % gav ett resultat med 79 % noggrannhet.

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Carberry, David Michael, and dave_carberry@yahoo com au. "Optical Tweezers: Experimental Demonstrations of the Fluctuation Theorem." The Australian National University. Research School of Chemistry, 2006. http://thesis.anu.edu.au./public/adt-ANU20060410.122727.

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In the late 19th and early 20th centuries famous scientists like Boltzmann, Loschmidt, Maxwell and Einstein tried, unsuccessfully, to find the link between the time-reversible equations of motion of individual molecules and irreversible thermodynamics. The solution to this puzzle was found in 1993, and the link is now known as the Fluctuation Theorem (FT). In the decade that followed theory and computer simulation tested the FT and, in 2002, an experiment indirectly demonstrated the FT.¶ This thesis describes original experiments that demonstrate the FT directly using Optical Tweezers. A related expression, known as the Kawasaki Identity, is also experimentally demonstrated. These experimental results provide a rigorous demonstration that irreversible dynamics can be obtained from a system with time-reversible dynamics.

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Aghababaie, Yashar. "Enhanced fluctuation-driven neutrino scattering behind supernova shocks." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=31179.

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We describe a general formalism for computing scattering rates of weak probes in macroscopic systems, based on a density matrix formalism. We show that weak probes in general scatter off fluctuations in the medium. In the limit that the neutrino wavelength is much larger than the lengthscale of the fluctuations, we show that the scattering rate can be calculated from knowledge of the equation of state of the medium through which the neutrinos travel. Using radial profiles of a post-bounce, shocked supernova core and a well-established equation of state for nuclear matter we compute these scattering rates for various times in the vicinity of the shock. We find that, behind the shock, these correlative effects can enhance neutrino scattering rates by factors of 8 compared to standard calculations which ignore interactions in the nuclear medium. These results may have implications for how efficiently neutrinos can restart a stalled shock, although firm conclusions regarding the ultimate effects of such an enhancement await full hydrodynamic simulations, which are not performed here.

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Banks, Simon Trevor. "Fluctuation of global quantities in highly correlated systems." Thesis, University College London (University of London), 2005. http://discovery.ucl.ac.uk/1444509/.

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This thesis addresses the nature of global (many body) fluctuations in highly correlated systems. We begin with the question of temperature dependence in finite two dimensional XY (2dXY) model magnets. Such systems have a fully critical low temperature phase. It is shown analytically, backed up by extensive Monte Carlo simulations, that the non-Gaussian distribution of order parameter fluctuations is not strictly universal but has an explicit temperature dependence - contrary to previous findings. The temperature dependence is used to explain why past studies derived the same distribution for fluctuations of the full order parameter and an approximate linearized form. The appearance of spin vortices in the related Harmonic model is discussed and an argument is presented for why these defects must always appear as bound pairs. The linearized order parameter of the 2dXY model leads to a family of dimensionally dependent models defined in reciprocal space. An argument is presented for the interpretation of these systems as being critical and a direct space Hamiltonian is derived for the one dimensional case. This model has order parameter fluctuations distributed according to the Fisher-Tippett-Gumbel distribution from extreme value statistics (EVS). The link between criticality and EVS is investigated, as are the origins of the non-Gaussianity. The ability to distinguish between critical distributions is discussed. It is seen that for one, two and three dimensions the critical models presented lead to functionally similar fluctuation distributions. A previously reported link between EVS and l/f noise is investigated. Our one dimensional critical model is mapped onto the action used to generate l/f signals and we propose an alternative interpretation of the link in the context of a 1/q dispersion of spatial normal modes. The experimental observability of the FTG distribution in l/f signals is considered with emphasis on imperfections in the noise. A physically relevant method of generating l/f noise from the superposition of random telegraph signals is also examined.

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Itoh, Kazuhito, and Masaki Sasai. "Entropic mechanism of large fluctuation in allosteric transition." National Academy of Sciences, 2010. http://hdl.handle.net/2237/20620.

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Golyk, Vladyslav Alexander. "Non-equilibrium fluctuation induced-phenomena in quantum electrodynamics." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/91076.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, 2014.
138
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 120-129).
We study fluctuation-induced phenomena in systems out of thermal equilibrium, resulting from the stochastic nature of quantum and thermal fluctuations of electromagnetic currents and waves. Specifically, we study radiative heat transfer and Casimir forces by applying the scattering formalism that expresses results solely in terms of the classical scattering matrices of the objects. For example, we obtain exact formulas for the heat radiation emitted by long cylindrical objects, as well as for Casimir forces that arise between them. We apply our results to explore the dependence of these phenomena on size and material properties of cylinders. While the scattering formalism is very general and technically can be employed for arbitrary shapes, in practice it is very time-consuming to apply it to the most experimentally-relevant and complex case of objects at close proximity. We examine easier ways to compute the heat transfer in such case. In particular, we develop a small distance expansion for the heat transfer between gently curved objects, in terms of the ratio of distance to radius of curvature. This expansion allows us to rigorously justify the widely used approach of "proximity transfer approximation", and to quantify corrections to it in the limit of small separation. Moreover, we study the role of surface roughness, and show that it may change the distance dependence of the heat transfer as well as Casimir forces between curved objects at proximity. Finally, as an alternative approach we construct general Green-Kubo relations that connect radiative heat transfer, non-equilibrium Casimir forces and vacuum friction between arbitrary objects to fluctuations in equilibrium which may be easier to consider from the perspective of experiment and simulations.
by Vladyslav Alexander Golyk.
Ph. D.

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Dorosz, Sven. "Fluctuation Relations for Stochastic Systems far from Equilibrium." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/26687.

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Fluctuations are of great importance in systems of small length and energy scales. Measuring the pulling of single molecules or the stationary fiow of mesospheres dragged through a viscous media enables the direct analysis of work and entropy distributions. These probability distributions are the result of a large number of repetitions of the same experiment. Due to the small scale of these experiments, the outcome can vary significantly from one realization to the next. Strong theoretical predictions exist, collectively called Fluctuation Theorems, that restrict the shape of these distributions due to an underlying time reversal symmetry of the microscopic dynamics. Fluctuation Theorems are the strongest existing statements on the entropy production of systems that are out of equilibrium. Being the most important ingredient for the Fluctuation Theorems, the probability distribution of the entropy change is itself of great interest. Using numerically exact methods we characterize entropy distributions for various stochastic reaction-diffusion systems that present different properties in their underlying dynamics. We investigate these systems in their steady states and in cases where time dependent forces act on them. This study allows us to clarify the connection between the microscopic rules and the resulting entropy production. The present work also adds to the discussion of the steady state properties of stationary probabilities and discusses a non-equilibrium current amplitude that allows us to quantify the distance from equilibrium. The presented results are part of a greater endeavor to find common rules that will eventually lead to a general understanding of non-equilibrium systems.
Ph. D.

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Horrell, J. M. "Investigation of broadband laser spectral fluctuation to CARS." Master's thesis, University of Cape Town, 1993. http://hdl.handle.net/11427/17383.

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Includes bibliographical references.
An investigation is made into the major factors contributing to shot-to-shot spectral fluctuations in a broadband dye laser with a view to reducing noise in Coherent Anti-Stokes Raman Spectroscopy (CARS). Combinations of three dyes and methods of quantifying noise in spectra are investigated. Correlations between groups of modes in the dye laser are shown to exist and vary from dye to dye. Investigation is made into the effects that the insertion of scattering particles into the dye laser oscillator has on the spectral noise. A tunable, solid state Ti:Sapphire laser is assembled and spectra obtained for comparison with the dye laser spectra.

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Prasad, Deepika. "Pursuit Evasion From Multiple Pursuers Using Speed Fluctuation." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1367928486.

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Carberry, David Michael. "Optical tweezers : experimental demonstrations of the fluctuation theorem /." View thesis entry in Australian Digital Theses Program, 2005. http://thesis.anu.edu.au/public/adt-ANU20060410.122727/index.html.

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Bellon, Ludovic Ciliberto Sergio. "Vieillissement des systèmes vitreux et rapport fluctuation-dissipation." [S.l.] : [s.n.], 2001. http://tel.archives-ouvertes.fr/tel-00003649.

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Buisson, Lionel Ciliberto Sergio. "Intermittence pendant le vieillissement et relation fluctuation dissipation." [S.l.] : [s.n.], 2003. http://tel.ccsd.cnrs.fr/tel-00005035.

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Саєнко, О. В., Я. Ю. Дима, and М. П. Красницький. "Використання програм-емуляторів для ілюстрації графіків гармонічних коливань." Thesis, Вид-во СумДУ, 2009. http://essuir.sumdu.edu.ua/handle/123456789/18245.

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Drmolová, Aneta. "Návrhy na snížení fluktuace výrobních dělníků konkrétní provozovny ve vybrané společnosti." Master's thesis, Vysoké učení technické v Brně. Fakulta podnikatelská, 2019. http://www.nusl.cz/ntk/nusl-399494.

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The diploma thesis focuses on the fluctuation of production workers specific establishment company Vodňanská poultry, a. s. The first part is devoted to explanation of the theoretical notions related to the topic - the most frequent causes, the methods of measurement or the costs associated with the departures of employees. Theoretical knowledges are in the next stage applicate for analysis and evaluation of the situation of the selected company. The final part contains suggestions for improving identified problems to reduce fluctuation.

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Constantin, Magdalena. "Persistence and survival aspects of fluctuation phenomena in surfaces." College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/2889.

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Thesis (Ph. D.) -- University of Maryland, College Park, 2005.
Thesis research directed by: Physics. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.

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Mouri, Kazunari. "Analyses of the Effects of Fluctuation in Biological Systems." 京都大学 (Kyoto University), 2009. http://hdl.handle.net/2433/123839.

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Li, Yan. "Mechanism of LNAPL migration in conjunction with groundwater fluctuation." 京都大学 (Kyoto University), 2005. http://hdl.handle.net/2433/144618.

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Kyoto University (京都大学)
0048
新制・課程博士
博士(地球環境学)
甲第11812号
地環博第6号
新制||地環||2(附属図書館)
23552
UT51-2005-F842
京都大学大学院地球環境学舎地球環境学専攻
(主査)教授嘉門雅史, 教授松井三郎, 助教授勝見武
学位規則第4条第1項該当

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Bulnes, Cuetara Gregory. "Fluctuation theorem for quantum electron transport in mesoscopic circuits." Doctoral thesis, Universite Libre de Bruxelles, 2013. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209435.

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Dans cette thèse nous étudions les propriétés statistique des courants dans des systèmes à l'échelle mésoscopique. Nous utilisons le formalisme de la statistique de comptage afin de caractériser les fluctuations de courant importantes à cette échelle. Celle-ci est obtenue en partant du Hamiltonien microscopique décrivant la dynamique des électrons sur le circuit considéré dans le régime quantique.

Nous considérons deux modèles particuliers de circuits à deux canaux, chacun comportant deux électrodes. Le premier modèle étudié est constitué de deux plots quantiques en couplage capacitif, et chacun échangeant des électrons avec deux électrodes. Le deuxième modèle est quant à lui constitué d'un double plot quantique connecté à deux électrodes et modulant le courant dans un point quantique formé lui-même par la jonction de deux électrodes. Pour ces deux modèles, chaque canal est soumis à une différence de potentiel, ou force thermodynamique, générant des courants stationnaires fluctuants.

La statistique des courants pour ces deux modèles est obtenue en utilisant une équation maîtresse pour les probabilités d'occupation dans les plots quantiques et le nombre d'électrons transférés entre ceux-ci et les électrodes. Nous vérifions que la distribution de probabilité jointes des courants dans chaque canal ainsi obtenue vérifie un théorème de fluctuation dans la limite des temps long faisant intervenir les forces thermodynamique des deux canaux.

La question de l'émergence d'un théorème de fluctuation effectif pour la distribution de probabilité marginale du courant dans un des deux canaux est également investiguée. Nous montrons que dans la limite ou le rapport des courants est grande, un tel théorème de fluctuation effectif est satisfait individuellement pour le canal de plus faible courant comme observé expérimentalement. Ce théorème fait intervenir une affinité effective dépendante des forces thermodynamiques des deux canaux et des spécificités du modèle considéré. Son étude détaillée est faite pour les deux modèles mentionnés.

Par ailleurs, nous posons également la question de l'existence d'un théorème de fluctuation pour des temps de mesure finis. Nous montrons qu'en présence d'un théorème de fluctuation dans la limite de temps longs, un critère peut être énoncé sur la condition initiale des plots quantiques menant à un théorème de fluctuations à temps fini. Ce critère est également étendu au cas des théorèmes de fluctuations effectifs.

Finalement, nous faisons une étude thermodynamique du modèle composé d'un double plot quantique en présence de différences de potentiel électrique et de température entre les électrodes du circuit.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished

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Dantu, Srilakshmi V. "Spin fluctuation resistivities of Fe-Ni-Zr metallic glasses." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59262.

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The effect of spin fluctuations on the resistivities of 14 different $Fe sb{x}Ni sb{1-x}Zr sb2$ metallic glasses were analyzed in the temperature range from 4.2K to 80K. The corrections to the resistivity due to the superconductivity and quantum interference effects at very low temperatures were performed to obtain the spin fluctuation resistivity, $ rho sb{sf}$, as a function of temperature and composition. It is found that, $ rho sb{sf}$ varies as $T sp2$ at very low temperatures, i.e. below around 20K, and as T at higher temperatures. This confirms the predictions of the two-band model of Kaiser and Doniach and the one-band model of Rivier and Zlatic. The spin fluctuation temperatures for all the compositions, were determined from both models. $T sb{sf}$ calculated from the one-band model were about 30% higher than those calculated from the two-band model. The spin fluctuation temperature is lowest when the system is closest to the magnetic transition and it increases when the amount of magnetic species is reduced in the alloy, i.e. for x = 1, $T sb{sf}$ = 10K (15K) and for x = 0.4, $T sb{sf}$ = 64K (96K) for the two-band (one-band) model.

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Ren, Wei, and 任偉. "Charge and spin conductance fluctuation and distribution in electronictransport." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B3761048X.

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Smith, Jill M. "Water table fluctuation in an East Central Indiana toposequence." Virtual Press, 1996. http://liblink.bsu.edu/uhtbin/catkey/1036198.

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Groundwater affects the development of soil in many ways. Due to the natural relationship between soil and groundwater this study was aimed at determining whether soils affect the water table depth, episaturation occurs, and hydric soils exist at the study site. The three soils studied include Pewamo (poorly drained), Blount (somewhat poorly drained) and Glynwood (moderately well drained).Water table data were collected in 1994 and 1995 at the Hults Environmental Learning Center in Albany, Indiana. Soil, by itself, was not found to be significant in affecting water table depth whereas position (horizon), soil by position and Julian date were all found to be highly significant. Soils were affected by existing drainage tile found in Pewamo that acted to lower the water table. Blount and Glynwood were found to have a period of episaturation whereas Pewamo was found to be endosaturated. The soils were not found to be hydric based on the depth to the water table only.
Department of Natural Resources and Environmental Management

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Boulineau, Rémi Louis Jean. "Super-resolution of photodynamic emitters by fluorescence fluctuation analysis." Thesis, University of Sussex, 2014. http://sro.sussex.ac.uk/id/eprint/47640/.

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A range of fluorescence fluctuation analysis methods were developed and applied to labels commonly used in biological samples. Various super-resolution techniques were demonstrated in vitro and in vivo using objective-type Total Internal Reflection Fluorescence Microscopy (TIRFM). An experimental Fluorescence Correlation Spectroscopy (FCS) setup was developed along with associated post-acquisition data algorithms. The technique was applied to investigate the stoichiometry of a protein subunit of ribonucleotide reductase (RNR). FCS method was adapted with an Electron Multiplying Charge Coupled Device (EMMCD) detection scheme and applied to inorganic Quantum Dots (QDs) diffusing in solutions of different viscosities. Super-resolution Optical Fluctuation Imaging (SOFI) algorithm was implemented in ImageJ software and conclusive results obtained on reference samples of QDs and combed DNA. Potential applications of temporal correlation analysis to the study of diffusive processes and single particle tracking were also discussed. A new super-resolution technique applicable to multiple adjacent fluorescent molecules called Direct Object Resolution by Image Subtraction (DORIS) was developed and tested with QD complexes. The method enables one to accurately map the position of two emitters displaying intermittency in their fluorescence emission and separated by a distance below the diffraction limit, without the need of complex instrumentation or analysis. The technique relies on the subtraction of the Point Spread Function (PSF) of each single fluorescent probe, and is in theory applicable to any blinking or flickering dye. The principle was first demonstrated on simulated data and experimentally on QDs coupled by 100-basepair double-stranded DNA constructs. Super-resolution by image subtraction was further applied in vivo in S. pombe cells, where distances between clustered fluorescent fusion proteins were accurately determined. The selective activation of photoswitchable probes mEos3 was exploited to optimise the DORIS subtraction process and provided a simple method to determine the relative positions of closely spaced emitters within an aggregate, as encountered in association sites or multimeric complexes.

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