Littérature scientifique sur le sujet « PDEs with coupled fluxes »
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Articles de revues sur le sujet "PDEs with coupled fluxes"
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Assefa, Migbar, Xin Lai, Lisheng Liu et Yang Liao. « Peridynamic Formulation for Coupled Thermoelectric Phenomena ». Advances in Materials Science and Engineering 2017 (2017) : 1–10. http://dx.doi.org/10.1155/2017/9836741.
Texte intégralRésumé :
Modeling of heat and electrical current flow simultaneously in thermoelectric convertor using classical theories do not consider the influence of defects in the material. This is because traditional methods are developed based on partial differential equations (PDEs) and lead to infinite fluxes at the discontinuities. The usual way of solving such PDEs is by using numerical technique, like Finite Element Method (FEM). Although FEM is robust and versatile, it is not suitable to model evolving discontinuities. To avoid such shortcomings, we propose the concept of peridynamic theory to derive the balance of energy and charge equations in the coupled thermoelectric phenomena. Therefore, this paper presents the transport of heat and charge in thermoelectric material in the framework of peridynamic (PD) theory. To illustrate the reliability of the PD formulation, numerical examples are presented and results are compared with those from literature, analytical solutions, or finite element solutions.
2
Ullah, Asad, Nahid Fatima, Khalid Abdulkhaliq M. Alharbi, Samia Elattar, Ikramullah Ikramullah et Waris Khan. « A Numerical Analysis of the Hybrid Nanofluid (AgTiO2Water) Flow in the Presence of Heat and Radiation Fluxes++ ». Energies 16, no 3 (22 janvier 2023) : 1220. http://dx.doi.org/10.3390/en16031220.
Texte intégralRésumé :
The hydrothermal characteristics of (Ag+TiO2+H2O) hybrid nanofluid three dimensional flow between two vertical plates, in which the right permeable plate stretches as well as rotates, are investigated by employing varying magnetic, heat and radiation fluxes. The motion is governed by coupled PDEs (nonlinear) obeying suitable boundary conditions. The PDEs coupled system is transformed to a coupled set of nonlinear ODEs employing appropriate similarity transformation relations. The resultant equations are numerically solved through the bv4c solver. The impact of the changing strength of associated parameters on the flow is investigated graphically and through tables. It has been found that the velocity gradient and velocity initially increase and then decrease with increasing Grashof number values in both the suction and injection cases. The enhancing magnetic field first augments and then lowers the velocity gradient in the presence of radiation source of maximum strength. The increasing strength of injection parameter drops the velocity. The temperature distribution in the fluid increases with the increasing Eckert number, radiation flux and heat strength and nanomaterial concentration, and depreciates with the enhancing injection parameter values and Prandtl number. The Cfx increases with a higher magnetic field magnitude and nanomaterial concentration, and declines with an increasing Grashof number. The results obtained are compared with the available literature in the form of tables.
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Zeleke, Migbar Assefa, Lai Xin et Li Sheng Liu. « Bond Based Peridynamic Formulation for Thermoelectric Materials ». Materials Science Forum 883 (janvier 2017) : 51–59. http://dx.doi.org/10.4028/www.scientific.net/msf.883.51.
Texte intégralRésumé :
Modeling of heat and electrical current flow simultaneously in thermoelectric convertor using classical theories do not consider the influence of defects in the material. This is because traditional methods are developed based on partial differential equations (PDEs) and lead to infinite fluxes and stress fields at the crack tips. The usual way of solving such PDEs is by using numerical technique, like Finite Element Method (FEM). Although FEM is robust and versatile, it is not suitable to model evolving discontinuities since discontinuous fields are mathematically singular at the crack tip and required an external criterion for the prediction of crack growth. In this paper, we follow the concept of peridynamic (PD) theory to overcome the shortcomings above. Therefore, the main aim of this paper is to develop the peridynamic equations for the generalized Fourier’s and Ohm’s laws. Furthermore, we derived the peridynamic equations for the conservation of energy and charge for the coupled thermoelectric phenomena.
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Jawad, Muhammad. « A Computational Study on Magnetohydrodynamics Stagnation Point Flow of Micropolar Fluids with Buoyancy and Thermal Radiation due to a Vertical Stretching Surface ». Journal of Nanofluids 12, no 3 (1 avril 2023) : 759–66. http://dx.doi.org/10.1166/jon.2023.1958.
Texte intégralRésumé :
In current analysis, A numerical approach for magnetohydrodynamics Stagnation point flow of Micropolar fluid due to a vertical stretching Surface is reported. The impact of buoyancy forces is considered. In additions the effects of the thermal radiation and thermal conductivity with non-zero mass flux have been analyzed. we implement the dimensionless variable technique and the systems of coupled non-linear PDEs are transformed into ODEs by using the appropriate similarity technique. Moreover, by using package ND-Solve on Mathematica problem is numerically integrated with the help of shooting technique. Numerical approach for magnetohydrodynamics Stagnation point flow of thermal Radiative Micropolar fluid due to a vertical stretching Surface. The impact of thermophoresis and Brownian motion are considered. We implement the dimensionless variable technique and the systems of coupled non-linear PDEs are transformed into ODEs by using the appropriate similarity technique. To observe the influence of the physical parameters, graphically valuations are performed for numerous emerging parameters like Brownian motion, mixed convection parameters, thermophoresis diffusion, Hartman number, Radiation parameter, Prandtl number, Stretching parameter and other dimension less parameters. These several protuberant parameters of interest are engaged for velocity, temperature and nonlinear micro rotation profile and studied in detail.
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Yates, Christian A., et Mark B. Flegg. « The pseudo-compartment method for coupling partial differential equation and compartment-based models of diffusion ». Journal of The Royal Society Interface 12, no 106 (mai 2015) : 20150141. http://dx.doi.org/10.1098/rsif.2015.0141.
Texte intégralRésumé :
Spatial reaction–diffusion models have been employed to describe many emergent phenomena in biological systems. The modelling technique most commonly adopted in the literature implements systems of partial differential equations (PDEs), which assumes there are sufficient densities of particles that a continuum approximation is valid. However, owing to recent advances in computational power, the simulation and therefore postulation, of computationally intensive individual-based models has become a popular way to investigate the effects of noise in reaction–diffusion systems in which regions of low copy numbers exist. The specific stochastic models with which we shall be concerned in this manuscript are referred to as ‘compartment-based’ or ‘on-lattice’. These models are characterized by a discretization of the computational domain into a grid/lattice of ‘compartments’. Within each compartment, particles are assumed to be well mixed and are permitted to react with other particles within their compartment or to transfer between neighbouring compartments. Stochastic models provide accuracy, but at the cost of significant computational resources. For models that have regions of both low and high concentrations, it is often desirable, for reasons of efficiency, to employ coupled multi-scale modelling paradigms. In this work, we develop two hybrid algorithms in which a PDE in one region of the domain is coupled to a compartment-based model in the other. Rather than attempting to balance average fluxes, our algorithms answer a more fundamental question: ‘how are individual particles transported between the vastly different model descriptions?’ First, we present an algorithm derived by carefully redefining the continuous PDE concentration as a probability distribution. While this first algorithm shows very strong convergence to analytical solutions of test problems, it can be cumbersome to simulate. Our second algorithm is a simplified and more efficient implementation of the first, it is derived in the continuum limit over the PDE region alone. We test our hybrid methods for functionality and accuracy in a variety of different scenarios by comparing the averaged simulations with analytical solutions of PDEs for mean concentrations.
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Mishra, S. R., S. Baag et S. K. Parida. « Entropy Generation Analysis on Magnetohydrodynamic Eyring-Powell Nanofluid Over a Stretching Sheet by Heat Source/Sink ». Journal of Nanofluids 11, no 4 (1 août 2022) : 537–44. http://dx.doi.org/10.1166/jon.2022.1861.
Texte intégralRésumé :
In this communication, the analysis of the entropy generation on magnetohydrodynamic (MHD) Eyring-Powell nanofluid over a stretching sheet with the effects of heat source/sink is reported. The presence of thermophoresis and Brownian motion are responsible for the enhancement in the properties of heat transfer. With the help of suitable similarity transformation entity, the involved governing partially differential equations (PDEs) are converted into nonlinear coupled ordinary differential equations (ODEs). Further, converted differential equations are solved by numerical methods such as Runge-Kutta fourth order correlated with shooting technique. Influence of various pertinent physical parameters is discussed via velocity, temperature, concentration and entropy profiles. The effect of these variables on the quantities of engineering advance such as Nusselt and Sherwood number are furnished in illustrative form and discussed. Further, the major findings of the outcomes are laid down as follows; the Brownian motion of the particles enhances the fluid temperature whereas thermophoresis retards significantly. The entropy generation overshoots due to the increase in the Reynolds number. Nanofluids with high critical heat fluxes and high-power density have the potential to provide the required cooling effect in military ships, submarines, wave energy converters and high-power laser diodes.
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Mahdy, A., et Ali J. Chamkha. « Unsteady MHD boundary layer flow of tangent hyperbolic two-phase nanofluid of moving stretched porous wedge ». International Journal of Numerical Methods for Heat & ; Fluid Flow 28, no 11 (5 novembre 2018) : 2567–80. http://dx.doi.org/10.1108/hff-12-2017-0499.
Texte intégralRésumé :
Purpose The purpose of this paper is to address the thermo-physical impacts of unsteady magneto-hydrodynamic (MHD) boundary layer flow of non-Newtonian tangent hyperbolic nanofluid past a moving stretching wedge. To delineate the nanofluid, the boundary conditions for normal fluxes of the nanoparticle volume fraction are chosen to be vanish. Design/methodology/approach The local similarity transformation is implemented to reformulate the governing PDEs into coupled non-linear ODEs of higher order. Then, numerical solution is obtained for the simplified governing equations with the aid of finite difference technique. Findings Numerical calculations point out that pressure gradient parameter leads to improve all skin friction coefficient, rate of heat transfer and absolute value of rate of nanoparticle concentration. As well as, lager values of Weissenberg number tend to upgrade the skin friction coefficient, while power law index and velocity ratio parameter reduce the skin friction coefficient. Again, the horizontal velocity component enhances with upgrading power law index, unsteadiness parameter, velocity ratio parameter and Darcy number and it reduces with rising values of Weissenberg number. Originality/value A numerical treatment of unsteady MHD boundary layer flow of tangent hyperbolic nanofluid past a moving stretched wedge is obtained. The problem is original.
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Veera Reddy, K., G. Venkata Ramana Reddy et Ali J. Chamkha. « Effects of Viscous Dissipation and Thermal Radiation on an Electrically Conducting Casson-Carreau Nanofluids Flow with Cattaneo-Christov Heat Flux Model ». Journal of Nanofluids 11, no 2 (1 avril 2022) : 214–26. http://dx.doi.org/10.1166/jon.2022.1836.
Texte intégralRésumé :
The primary goal of this research is to study the Cattaneo-Christov heat flux model on the impacts of mass and energy transit of MHD Casson-Carreu nanofluid through a permeable vertical accelerating plate with Soret and Dufour mechanism. The non-Newtonian fluids flowed over the porous vertical plate to reach the boundary layer in this investigation. In order to understand the physical model, partial differential equations (PDEs) are used. To get a linked nonlinear set of ordinary differential equations (ODEs), we reduced this set of PDEs by using similarity variables. SHAM, a spectrum basis technique, was utilized to solve these modified equations to understand the physical significance. A good method is to utilize SHAM to decouple the coupled nonlinear ODE systems and divide them into linear and nonlinear equation sets since this helps to separate the systems. As a result, the two non-Newtonian fluids (Carreu and Cassin) flow together through the vertical wall and into the boundary layer, where different parameters’ impacts are scrutinized. The current results showed that an upturn in the Casson parameter (β) degenerates the boundary layer velocity and the total thickness. Upturn in the Weissenberg number (We) on the other hand, raises the velocities and temperatures in both directions. Additionally, increasing the Soret and Dufour parameters sped up the velocity graph.
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Harrison, Jonathan U., et Christian A. Yates. « A hybrid algorithm for coupling partial differential equation and compartment-based dynamics ». Journal of The Royal Society Interface 13, no 122 (septembre 2016) : 20160335. http://dx.doi.org/10.1098/rsif.2016.0335.
Texte intégralRésumé :
Stochastic simulation methods can be applied successfully to model exact spatio-temporally resolved reaction–diffusion systems. However, in many cases, these methods can quickly become extremely computationally intensive with increasing particle numbers. An alternative description of many of these systems can be derived in the diffusive limit as a deterministic, continuum system of partial differential equations (PDEs). Although the numerical solution of such PDEs is, in general, much more efficient than the full stochastic simulation, the deterministic continuum description is generally not valid when copy numbers are low and stochastic effects dominate. Therefore, to take advantage of the benefits of both of these types of models, each of which may be appropriate in different parts of a spatial domain, we have developed an algorithm that can be used to couple these two types of model together. This hybrid coupling algorithm uses an overlap region between the two modelling regimes. By coupling fluxes at one end of the interface and using a concentration-matching condition at the other end, we ensure that mass is appropriately transferred between PDE- and compartment-based regimes. Our methodology gives notable reductions in simulation time in comparison with using a fully stochastic model, while maintaining the important stochastic features of the system and providing detail in appropriate areas of the domain. We test our hybrid methodology robustly by applying it to several biologically motivated problems including diffusion and morphogen gradient formation. Our analysis shows that the resulting error is small, unbiased and does not grow over time.
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Jabeen, K., M. Mushtaq et R. M. Akram Muntazir. « Analysis of MHD Fluids around a Linearly Stretching Sheet in Porous Media with Thermophoresis, Radiation, and Chemical Reaction ». Mathematical Problems in Engineering 2020 (7 mai 2020) : 1–14. http://dx.doi.org/10.1155/2020/9685482.
Texte intégralRésumé :
This paper presents the comparative analysis of MHD boundary layer fluid flow around a linearly stretching surface in the presence of radiative heat flux, heat generation/absorption, thermophoresis velocity, and chemical reaction effects in a permeable surface. The governing equations are highly nonlinear PDEs which are converted into coupled ODEs with the help of dimensionless variables and solved by using semianalytical techniques. The numerical and graphical outcomes are observed and presented via tables and graphs. Also, the Nusselt and Sherwood numbers and skin friction coefficient are illustrated by tables. On observation of heat and mass transfer, it was noticed that Maxwell fluid dominates the other fluids such as Newtonian, Williamson, and Casson fluid due to high rate of thermal conductivity, and hence, Maxwell fluid has better tendency for heat and mass transfer than other Newtonian and non-Newtonian fluids.
Thèses sur le sujet "PDEs with coupled fluxes"
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VO, ANK KHOA. « Corrector homogenization estimates for PDE Systems with coupled fluxes posed in media with periodic microstructures ». Doctoral thesis, Gran Sasso Science Institute, 2018. http://hdl.handle.net/20.500.12571/9693.
Texte intégralRésumé :
The purpose of this thesis is the derivation of corrector estimates justifying the upscaling
of systems of partial differential equations (PDEs) with coupled fluxes posed in media with
microstructures (like porous media). Such models play an important role in the understanding of, for example, drug-delivery mechanisms, where the involved chemical species
diffusing inside the domain are assumed to obey perhaps other transport mechanisms and
certain non-dissipative nonlinear processes within the pore space and at the boundaries of
the perforated media (e.g. interaction, chemical reaction, aggregation, deposition). In this
thesis, our corrector estimates provide a quantitative analysis in terms of convergence rates
in suitable norms, i.e. as the small homogenization parameter tends to zero, the differences
between the micro- and macro-concentrations and between the corresponding micro- and
macro-concentration gradients are controlled in terms of the small parameter. As preparation, we are first concerned with the weak solvability of the microscopic models as well as
with the fundamental asymptotic homogenization procedures that are behind the derivation
of the corresponding upscaled models. We report results on three connected mathematical
problems:
1. Asymptotic analysis of microscopic semi-linear elliptic equations/systems. We explore the
asymptotic analysis of a prototype model including the interplay between stationary diffusion and both surface and volume chemical reactions in porous media. Our interest
lies in deriving homogenization limits (upscaling) for alike systems, and particularly, in
justifying rigorously the obtained averaged descriptions. We prove the well-posedness
of the microscopic problem ensuring also the positivity and boundedness of the involved concentrations. Then we use the structure of the two-scale expansions to derive
corrector estimates delimitating quantitatively the convergence rate of the asymptotic
approximates to the macroscopic limit concentrations and their gradients. High-order
corrector estimates are also obtained. The semi-linear auxiliary problems are tackled
by a fixed-point homogenization argument. Our techniques include also Moser-like iteration techniques, a variational formulation, two-scale asymptotic expansions as well
as suitable energy estimates.
2. Corrector estimates for a Smoluchowski-Soret-Dufour model. We consider a thermodiffusion system, which is a coupled system of PDEs and ODEs that account for the
heat-driven diffusion dynamics of hot colloids in periodic heterogeneous media. This
model describes the joint evolution of temperature and colloidal concentrations in a
saturated porous tissue where the Smoluchowski interactions for aggregation process
and a linear deposition process take place. By a fixed-point argument, we prove the
local existence and uniqueness results for the upscaled system. To obtain the corrector
estimates, we exploit the concept of macroscopic reconstructions as well as suitable
integral estimates to control boundary interactions.
3. Corrector estimates for a non-stationary Stokes-Nernst-Planck-Poisson system. We investigate a non-stationary Stokes-Nernst-Planck-Poisson system posed in a perforated domain as originally proposed by Knabner and his co-authors (see e.g. [98] and [99]).
Starting off with the setting from [99], we complete the results by proving corrector estimates for the homogenization procedure. Main difficulties are connected to the choice
of boundary conditions for the Poisson part of the system as well as with the scaling of
the Stokes part of the system.
2
BACCOLI, ANTONELLO. « Boundary control and observation of coupled parabolic PDEs ». Doctoral thesis, Università degli Studi di Cagliari, 2016. http://hdl.handle.net/11584/266880.
Texte intégralRésumé :
Reaction-diffusion equations are parabolic Partial Differential Equations (PDEs) which
often occur in practice, e.g., to model the concentration of one or more substances, distributed
in space, under the in
uence of different phenomena such as local chemical reactions,
in which the substances are transformed into each other, and diffusion, which causes
the substances to spread out over a surface in space. Certainly, reaction-diffusion PDEs
are not confined to chemical applications but they also describe dynamical processes of
non-chemical nature, with examples being found in thermodynamics, biology, geology,
physics, ecology, etc.
Problems such as parabolic Partial Differential Equations (PDEs) and many others
require the user to have a considerable background in PDEs and functional analysis before
one can study the control design methods for these systems, particularly boundary control
design.
Control and observation of coupled parabolic PDEs comes in roughly two settingsdepending
on where the actuators and sensors are located \in domain" control, where
the actuation penetrates inside the domain of the PDE system or is evenly distributed
everywhere in the domain and \boundary" control, where the actuation and sensing are
applied only through the boundary conditions.
Boundary control is generally considered to be physically more realistic because actuation
and sensing are nonintrusive but is also generally considered to be the harder problem,
because the \input operator" and the "output operator" are unbounded operators.
The method that this thesis develops for control of PDEs is the so-called backstepping
control method. Backstepping is a particular approach to stabilization of dynamic
systems and is particularly successful in the area of nonlinear control. The backstepping
method achieves Lyapunov stabilization, which is often achieved by collectively shifting
all the eigenvalues in a favorable direction in the complex plane, rather than by assigning
individual eigenvalues. As the reader will soon learn, this task can be achieved in a rather
elegant way, where the control gains are easy to compute symbolically, numerically, and
in some cases even explicitly.
In addition to presenting the methods for boundary control design, we present the dual
methods for observer design using boundary sensing. Virtually every one of our control
designs for full state stabilization has an observer counterpart. The observer gains are
easy to compute symbolically or even explicitly in some cases. They are designed in
such a way that the observer error system is exponentially stabilized. As in the case of
finite-dimensional observer-based control, a separation principle holds in the sense that a
closed-loop system remains stable after a full state stabilizing feedback is replaced by a
feedback that employs the observer state instead of the plant state.
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Alhazmi, Muflih. « Exploring mechanisms for pattern formation through coupled bulk-surface PDEs ». Thesis, University of Sussex, 2018. http://sro.sussex.ac.uk/id/eprint/78232/.
Texte intégralRésumé :
This work explores mechanisms for pattern formation through coupled bulksurface partial differential equations of reaction-diffusion type. Reaction-diffusion systems posed both in the bulk and on the surface on stationary volumes are coupled through linear Robin-type boundary conditions. In this framework we study three different systems as follows (i) non-linear reactions in the bulk and surface respectively, (ii) non-linear reactions in the bulk and linear reactions on the surface and (iii) linear reactions in the bulk and non-linear reactions on the surface. In all cases, the systems are non-dimensionalised and rigorous linear stability analysis is carried out to determine the necessary and sufficient conditions for pattern formation. Appropriate parameter spaces are generated from which model parameters are selected. To exhibit pattern formation, a coupled bulk-surface finite element method is developed and implemented. We implement the numerical algorithm by using an open source software package known as deal.II and show computational results on spherical and cuboid domains. Theoretical predictions of the linear stability analysis are verified and supported by numerical simulations. The results show that non-linear reactions in the bulk and surface generate patterns everywhere, while non-linear reactions in the bulk and linear reactions on the surface generate patterns in the bulk and on the surface with a pattern-less thin boundary layer. However, linear reactions in the bulk do not generate patterns on the surface even when the surface reactions are non-linear. The generality, robustness and applicability of our theoretical computational framework for coupled system of bulk-surface reaction-diffusion equations set premises to study experimentally driven models where coupling of bulk and surface chemical species is prevalent. Examples of such applications include cell motility, pattern formation in developmental biology, material science and cancer biology.
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Liu, Bainan. « Boundary Observer-based 0utput Feedback Control of Coupled Parabolic PDEs ». Thesis, Bourges, INSA Centre Val de Loire, 2018. http://www.theses.fr/2018ISAB0011.
Texte intégralRésumé :
Cette thèse vise à concevoir un contrôleur basé observateur au bord pour une classede systèmes modélisés par des équations aux dérivées partielles (EDP) paraboliquescouplées en utilisant la méthode dite backstepping. Grosso modo, la méthode dubackstepping pour les EDP consiste principalement à les transformer sous certainesformes faciles à analyser et à stabiliser à l’aide de contrôleurs ou d’observateurs. Cesformes seront appelées les systèmes cibles. Tout d’abord, ce travail considère un cassimple d’équations couplées avec des paramètres de diffusion constants. Pour ce cas,on met en évidence des conditions de stabilité moins contraignantes que les conditionsproposées dans la littérature sur ce sujet. De plus, pour le même cas, on conçoitune commande par retour d’état basé observateur. Ensuite, on donne une simulationsur un exemple pour prouver la consistance de la méthode proposée. Ce travail traiteégalement d’une classe de systèmes modélisés par équations de réaction-advectiondiffusionavec le même paramètre de diffusion constant en proposant des conditionsparticulières sur les systèmes cibles. Dans un second temps, on traite le cas des équationscouplées réaction-diffusion avec différentes diffusions. Cependant, comme lestermes de diffusions sont différents, il est plus difficile de calculer le noyau de la transformationbackstepping. Pour surmonter cette difficulté, on fait une hypothèse sur lenoyau qui définit la transformation backstepping. De plus, on conçoit également uncontrôleur basé observateur avec les mêmes conditions de stabilité proposées pour lesdeux premières situations. Ensuite, on utilise le principe de séparation pour concevoirun contrôleur basé observateur. Enfin, on utilise un modèle simplifié de réacteurtubulaire pour mettre en évidence la cohérence de la méthode proposée. Dans unetroisième partie, cette thèse étend ces résultats à une classe de systèmes modéliséspar des équations couplées de réaction-advection-diffusion à coefficients dépendantde la variable d’espace, ce qui rend la détermination du noyau de la transformationbackstepping plus difficile. Pour ce faire, on transforme les équations aux dérivéespartielles paraboliques qui définissent le noyau de la transformation en un ensembled’équations hyperboliques. Par conséquent, on peut prouver que le problème est bienposé en fixant des conditions aux limites appropriées pour la fonction noyau. De plus,on fournit également les conditions de stabilité pour les systèmes cibles. La performancede l’observateur proposé est illustrée sur un modèle numérique. Puis, on étendle contrôleur basé observateur aux systèmes EDP d’ordre fractionnaire. Enfin, desconclusions sont présentées avec quelques perspectivesThis thesis aims to design a boundary observer-based output feedback controllerfor a class of systems modelled by linear coupled parabolic PDEs by using the backsteppingmethod.Roughly speaking, the backstepping method for PDEs mainly consists oftransforming some kinds of PDEs into some particular PDEs, that are easy to analyzeand stabilize by using controllers or observers. This kind of particular PDEs will becalled target systems. Firstly, it considers an easy case of coupled reaction-diffusionequations with the same constant diffusion parameter. For this case, it proposes amore relaxed stability condition for the target system of the backstepping transformation.Moreover, for the same case, it designs a backstepping boundary observer-basedoutput feedback controller. Then, it takes an example to verify the proposed method.It also deals with a class of systems modelled by reaction-advection-diffusion equationswith the same constant diffusion parameter, which are realized by proposingparticular conditions on the target systems. Secondly, it deals with a kind of systemsmodelled by coupled reaction-diffusion equations with different diffusions. In a similarway, it designs a boundary observer for this kind of systems. However, due to thefact that the constant diffusions are not the same, it is more difficult to solve the kernelfunctions of the backstepping transformation than the same diffusion case. Forthis, an assumption on the kernel functions is made to enable us to solve the problem.Moreover, it also designs a backstepping boundary controller based on the proposedstability conditions. Those stability conditions are more relaxed than the conditionswe can find in the literatures on this topic. Then, based on the Separation Principle,it designs an observer-based output feedback controller. It takes a simplified modelof Chemical Tubular Reactor to highlight the proposed method. Thirdly, this thesisdesigns a boundary observer as a more general extension by studying a class of systemsmodelled by coupled reaction-advection-diffusion equations with spatially-varyingcoefficients, which is more challenged to solve kernel functions of the backsteppingtransformation. To achieve this, it transforms the parabolic kernel equations into a setof hyperbolic equations. Then, it proves the well-posedness by setting suitable boundaryconditions for the kernel functions. Moreover, it also provides the stability conditionsfor the target systems. The performance of the proposed observer is illustrated bytaking a numerical model. Fourthly, it extends the above backstepping observer-basedoutput feedback controller to fractional-order PDE systems. Finally, conclusions areoutlined with some perspectives
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Sharma, Preeti. « Coupled electrokinetic fluxes in a single nanochannel for energy conversion ». Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAY100/document.
Texte intégralRésumé :
Les phénomènes électrocinétiques couplés au sein d'un nanocanal sont d'intérêt pour la conversion d'énergie et la production d'électricité reposant sur le mélange contrôlé d'eau douce et d'eau salée aussi appelée "énergie bleue". L'origine des phénomènes est lié à l'interaction avec des parois chargées et au transport d'ions au sein de ce qu'on nomme les couches de Debye. Ce travail vise à une meilleure compréhension de la physique et des phénomènes de transport dans ces couches dans le cadre de solutions confinées dans des nanocanaux.Une instrumentation spécifique a été développée pendant la thèse pour étudier les mécanismes qui gouvernent ces flux couplés. L'idée est de caractériser simultanément le transport de masse et le courant électrique au sein d'un nanocanal soumis à une différence de salinité de pression ou de tension électrique. Ce travail est divisé en trois parties.Dans la première partie, est décrite une cellule conçue pour la mesure et le contrôle de courant et tension électrique en présence de différence de pression ou de salinité au bornes d'un nanopores. L'utilisation de la cellule est illustrer dans le cas d'une membrane nanoporeuse de nafion.La seconde partie est focalisée sur une méthode simple de préparation d'un nanocanal directement connectable à un dispositif macroscopique. Le nanocanal, d'un micromètre de long, présente une géométrie conique, d'angle ajustable, et des extrémités équipées d'électrode déposées par pulvérisation cathodique.La troisième partie, concerne le développement d'une méthode pour la mesure directe de débit jusqu'à 10 pL/min s'écoulant au sein d'un nanocanal. Cette méthode combinée à une caractérisation électrique, pourra être utilisée, en présence de gradient de pression, de tension ou de salinité pour mesurer le débit et le courant électrique au sein d'un nanocanal de manière simultanée et indépendanteCoupled electrokinetic phenomena within nanochannel are of interest for energy harvestingand production of electricity based on the controlled mixing of river water with sea water known as "blue energy". The origin of the phenomena is related to interaction with charged walls and transport of ions within the so called Debye layer. This work aims at a better understanding of the physics and transport phenomena in this layer associated with solution confined in nanochannel.A specific instrumentation has been developed during this thesis to study the mechanisms governing coupled nanofluics fluxes. The idea is to characterize simultaneously the mass transport within the nanochannel and the electrical current driven through the nanochannel by the application of either salinity difference , pressure difference or voltage difference across the channel. The thesis is divided into three parts.In the first part, a custom made flow cell and experimental conditions to control and measure various fluxes is presented. The capability of cell to measure current or voltage under applied pressure or salinity gradient is presented taking the benefit of commercial nanoporous Nafion membrane.The second part is focused on an easy way of preparation of nanochannel sample in the form of single chip, in which nanochannel is interfaced to micro and macroscopic world. A well-controlled, 1.4µm long nanochannel of conical geometry with a maximum aspect ratio of 10 is fabricated. The minimum apex size of nanochannel achieved here is 50 nm which is about 30 times less than the length of channel. The presence of electrode directly at the interface of nano to micro cavity allow to perform electrical characterization of nanochannel with high precision.The third part of the thesis is devoted to the development of a method for the direct measurement of flow rate as low as 10 pL/min across a single nanochannel. This measurement approach combined with electrical measurement, could be used, in presence of pressure, voltage or salinity gradient, to measure the flow rate and the electrical current across a single nanochannel simultaneously and independently
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Zhang, Lejie. « Fluorescent Visualization of Cellular Proton Fluxes ». eScholarship@UMMS, 2018. https://escholarship.umassmed.edu/gsbs_diss/999.
Texte intégralRésumé :
Proton fluxes through plasma membranes are essential for regulating intracellular and extracellular pH and mediating co-transport of metabolites and ions. Although conventional electrical measurements are highly sensitive and precise for proton current detection, they provide limited specificity and spatial information. My thesis focuses on developing optical approaches to visualize proton fluxes from ion channels and transporters.
It has been demonstrated that channel-mediated acid extrusion causes proton depletion at the inner surface of the plasma membrane. Yet, proton dynamics at the extracellular microenvironment are still unclear. In Chapter II, we developed an optical approach to directly measure pH change in this nanodomain by covalently attaching small-molecule, fluorescent proton sensors to the cell’s glycocalyx using glyco-engineering and copper free ‘click’ chemistry. The extracellularly facing sensors enable real-time detection of proton accumulation and depletion at the plasma membrane, providing an indirect readout of channel and transporter activity that correlated with whole-cell proton current. Moreover, the proton wavefront emanating from one cell was readily visible as it crossed over nearby cells.
The transport of monocarboxylates, such as lactate and pyruvate is critical for energy metabolism and is mainly mediated by proton-coupled monocarboxylate transporters (MCT1-MCT4). Although pH electrodes and intracellular fluorescent pH sensors have been widely used for measuring the transport of proton-coupled MCTs, they are unable to monitor the subcellular activities and may underestimate the transport rate due to cell’s volume and intracellular buffering. In Chapter III, we used the Chapter II approach to visualize proton-coupled transport by MCT1-transfected HEK293T cells and observed proton depletion followed by a recovery upon extracellular perfusion of L-lactate or pyruvate. In addition, we identified a putative MCT, CG11665/Hrm that is essential for autophagy during cell death in Drosophila. The results demonstrate that Hrm is a bona fide proton-coupled monocarboxylate transporter that transports pyruvate faster than lactate.
Although the approach developed in Chapter II enables visualization of proton fluxes from ion channels and transporters, it’s not applicable in some cell types which cannot incorporate unnatural sialic acid precursors into their glycocalyx, such as INS-1 cells and cardiomyocytes. To address this, in Chapter IV we developed a pH-sensitive, fluorescent WGA conjugate, WGA-pHRho that binds to endogenous glycocalyx. Compared to the results in Chapter II and III, cell surface-attached WGA-pHRho has similar fluorescent signals in response to proton fluxes from proton channel Hv1, omega mutant Shaker-IR R362H and MCT1. With WGA-pHRho, we were able to label the plasma membrane of INS-cells and cardiomyocytes and visualized the transport activity of MCT1 in these cells.
Taken together, these findings provide news insights into proton dynamics at the extracellular environment and provide new optical tools to visualize proton fluxes from ion channels and transporters. Moreover, the modularity of the approaches makes them adaptable to study any transport events at the plasma membrane in cells, tissues, and organisms.
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Zheng, Lu. « Examining the impact of wildfire smoke aerosol on clouds, precipitation, and radiative fluxes in Northern America and Russia using a fully coupled meso-scale model WRF-Chem-SMOKE and satellite data ». Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/52338.
Texte intégralRésumé :
We developed a fully-coupled meso-scale model WRF-Chem-SMOKE by incorporating a selection of smoke emission models and improving the representations of aerosol-cloud interactions in the microphysics scheme. We find that the difference in smoke emissions between different datasets, even in one fire cluster, could lead to significant discrepancies in modeled AODs. The integrated smoke emission dataset improves the prediction of modeled AODs. We find that the modeled cloud properties and precipitation are extremely sensitive to the smoke loadings. Higher smoke loadings suppress precipitation initially, because of smoke-induced reduction of the collision-coalescence and riming processes, but ultimately cause an invigoration of precipitation.
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Soudani, Lucile Caroline Laurence. « Modelling and experimental validation of the hygrothermal performances of earth as a building material ». Thesis, Lyon, 2016. http://www.theses.fr/2016LYSET011/document.
Texte intégralRésumé :
La thèse s'inscrit dans un projet de recherche national (ANR Primaterre) qui a pour but d'étudier les performances (mécaniques et thermiques) réelles des matériaux de construction premiers à faible énergie grise que sont la terre crue et la limousinerie.Le travail de thèse se concentre sur les aspects thermiques et hygrothermiques de la terre crue, c'est-à-dire le couplage entre les transferts de masse d'eau (liquide et vapeur) et de chaleur au sein du matériau. Dans une première partie, une analyse des performances thermiques et hydriques d'une habitation comportant des murs en pisé (terre crue compactée) instrumentés a été réalisée. Cette étude a été complétée par la mesure, en laboratoire, des propriétés thermiques et hydriques du matériau. Le lien entre les paramètres matériaux mesurés et les performances (hygro)-thermiques a été appréhendé à la lumière d'un modèle numérique couplé, adapté aux caractéristiques particulières du matériau. Cette étude a mis en évidence que, de par leur aptitude à stocker puis restituer l'énergie solaire, leur capacité de stockage hydrique et la complexité des transports et changements de phases de l'eau se produisant en leur sein, les murs en terre crue présentent de nombreuses particularités qu'il convient de prendre en compte pour une bonne prédiction de leur impact sur les performances d'une habitationThe Ph.D. is part of a national research project (ANR Primaterre) aiming at promoting real performances (mechanical and thermal) of primary construction materials with low embodied energy such as raw earth.This work focuses on the thermal and hygrothermal behaviour of rammed earth, i.e. coupled transfers of heat and moisture (liquid water and water vapour) within the material. On the one hand, an evaluation of the thermal and hygric performances of a monitored house with rammed earth walls is provided. This study is completed with laboratory measurements of the thermal and hydric properties of the material. A numerical coupled model, suitable for the specific characteristics of the material, provides a better understanding of the link between the characterization parameters measured and its (hygro)thermal performances. Because of their ability to store and release heat from the sun, their capacity to store moisture and the complexity of the transfers occurring in their pores, earthen walls display many distinctive features that are essential to count for in order to provide an accurate prediction of their impact on the global performances of a building
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Toufayli, Laila. « Stabilisation polynomiale et contrôlabilité exacte des équations des ondes par des contrôles indirects et dynamiques ». Phd thesis, Université de Strasbourg, 2013. http://tel.archives-ouvertes.fr/tel-00780215.
Texte intégralRésumé :
La thèse est portée essentiellement sur la stabilisation et la contrôlabilité de deux équations des ondes moyennant un seul contrôle agissant sur le bord du domaine. Dans le cas du contrôle dynamique, le contrôle est introduit dans le système par une équation différentielle agissant sur le bord. C'est en effet un système hybride. Le contrôle peut être aussi applique directement sur le bord d'une équation, c'est le cas du contrôle indirecte mais non borne. La nature du système ainsi coupledépend du couplage des équations, et ceci donne divers résultats par la stabilisation (exponentielle et polynomiale) et la contrôlabilité exacte (espace contrôlable). Des nouvelles inégalités d'énergie permettent de mettre en oeuvre la Méthode fréquentielle et la Méthode d'Unicité de Hilbert.
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Singh, Gurpreet 1984. « Coupled flow and geomechanics modeling for fractured poroelastic reservoirs ». Thesis, 2014. http://hdl.handle.net/2152/28473.
Texte intégralRésumé :
Tight gas and shale oil play an important role in energy security and in meeting an increasing energy demand. Hydraulic fracturing is a widely used technology for recovering these resources. The design and evaluation of hydraulic fracture operation is critical for efficient production from tight gas and shale plays. The efficiency of fracturing jobs depends on the interaction between hydraulic (induced) and naturally occurring discrete fractures. In this work, a coupled reservoir-fracture flow model is described which accounts for varying reservoir geometries and complexities including non-planar fractures. Different flow models such as Darcy flow and Reynold's lubrication equation for fractures and reservoir, respectively are utilized to capture flow physics accurately. Furthermore, the geomechanics effects have been included by considering a multiphase Biot's model. An accurate modeling of solid deformations necessitates a better estimation of fluid pressure inside the fracture. The fractures and reservoir are modeled explicitly allowing accurate representation of contrasting physical descriptions associated with each of the two. The approach presented here is in contrast with existing averaging approaches such as dual and discrete-dual porosity models where the effects of fractures are averaged out. A fracture connected to an injection well shows significant width variations as compared to natural fractures where these changes are negligible. The capillary pressure contrast between the fracture and the reservoir is accounted for by utilizing different capillary pressure curves for the two features. Additionally, a quantitative assessment of hydraulic fracturing jobs relies upon accurate predictions of fracture growth during slick water injection for single and multistage fracturing scenarios. It is also important to consistently model the underlying physical processes from hydraulic fracturing to long-term production. A recently introduced thermodynamically consistent phase-field approach for pressurized fractures in porous medium is utilized which captures several characteristic features of crack propagation such as joining, branching and non-planar propagation in heterogeneous porous media. The phase-field approach captures both the fracture-width evolution and the fracture-length propagation. In this work, the phase-field fracture propagation model is briefly discussed followed by a technique for coupling this to a fractured poroelastic reservoir simulator. We also present a general compositional formulation using multipoint flux mixed finite element (MFMFE) method on general hexahedral grids with a future prospect of treating energized fractures. The mixed finite element framework allows for local mass conservation, accurate flux approximation and a more general treatment of boundary conditions. The multipoint flux inherent in MFMFE scheme allows the usage of a full permeability tensor. An accurate treatment of diffusive/dispersive fluxes owing to additional velocity degrees of freedom is also presented. The applications areas of interest include gas flooding, CO₂ sequestration, contaminant removal and groundwater remediation.text
Livres sur le sujet "PDEs with coupled fluxes"
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Mathematical control theory of coupled PDEs. Philadelphia : Society for Industrial and Applied Mathematics, 2002.
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Zeitlin, Vladimir. Rotating Shallow-Water Models with Moist Convection. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198804338.003.0015.
Texte intégralRésumé :
It is shown how the standard RSW can be ’augmented’ to include phase transitions of water. This chapter explains how to incorporate extra (convective) vertical fluxes in the model. By using Lagrangian conservation of equivalent potential temperature condensation of the water vapour, which is otherwise a passive tracer, is included in the model and linked to convective fluxes. Simple relaxational parameterisation of condensation permits the closure of the system, and surface evaporation can be easily included. Physical and mathematical properties of thus obtained model are explained, and illustrated on the example of wave scattering on the moisture front. The model is applied to ’moist’ baroclinic instability of jets and vortices. Condensation is shown to produce a transient increase of the growth rate. Special attention is paid to the moist instabilities of hurricane-like vortices, which are shown to enhance intensification of the hurricane, increase gravity wave emission, and generate convection-coupled waves.
Chapitres de livres sur le sujet "PDEs with coupled fluxes"
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Yu, Huan, et Miroslav Krstic. « Backstepping for Coupled Hyperbolic PDEs ». Dans Systems & ; Control : Foundations & ; Applications, 25–45. Cham : Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-19346-0_2.
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Guo, Bao-Zhu, et Jun-Min Wang. « Stabilization of Coupled Systems Through Boundary Connection ». Dans Control of Wave and Beam PDEs, 505–92. Cham : Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-12481-6_6.
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Bayen, Alexandre, Maria Laura Delle Monache, Mauro Garavello, Paola Goatin et Benedetto Piccoli. « Lagrangian Control of Conservation Laws and Mixed Models ». Dans Control Problems for Conservation Laws with Traffic Applications, 111–38. Cham : Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-93015-8_5.
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AbstractA vehicle with different (eventually controlled) dynamics from general traffic along a street may reduce the road capacity, thus generating a moving bottleneck, and can be used to act on the traffic flow. The interaction between the controlled vehicle and the surrounding traffic, and the consequent flow reduction at the bottleneck position, can be described either by a conservation law with space dependent flux function [200], or by a strongly coupled PDE-ODE system proposed in [112, 208].
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Schneider, Falco. « On the Discretization of Diffusion Fluxes for a System of PDEs ». Dans Mathematics in Industry, 289–95. Cham : Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-11818-0_38.
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Hernández-Santamaría, Víctor, et Luz de Teresa. « Some Remarks on the Hierarchic Control for Coupled Parabolic PDEs ». Dans SEMA SIMAI Springer Series, 117–37. Cham : Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-97613-6_7.
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Laurino, Federica, Stefano Brambilla et Paolo Zunino. « A Posteriori Model Error Analysis of 3D-1D Coupled PDEs ». Dans Lecture Notes in Computational Science and Engineering, 663–71. Cham : Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-55874-1_65.
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Yücel, Hamdullah, et Peter Benner. « Distributed Optimal Control Problems Governed by Coupled Convection Dominated PDEs with Control Constraints ». Dans Lecture Notes in Computational Science and Engineering, 469–78. Cham : Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-10705-9_46.
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Dargaville, R. J., et I. Simmonds. « Calculating CO2 fluxes by data assimilation coupled to a three dimensional mass balance inversion ». Dans Inverse Methods in Global Biogeochemical Cycles, 255–64. Washington, D. C. : American Geophysical Union, 2000. http://dx.doi.org/10.1029/gm114p0255.
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Gulliver, R., W. Littman, I. Lasiecka et R. Triggiani. « The Case for Differential Geometry in the Control of Single and Coupled PDEs : The Structural Acoustic Chamber ». Dans Geometric Methods in Inverse Problems and PDE Control, 73–181. New York, NY : Springer New York, 2004. http://dx.doi.org/10.1007/978-1-4684-9375-7_5.
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Irscheid, Abdurrahman, Nicole Gehring, Joachim Deutscher et Joachim Rudolph. « Tracking Control for $$2\times 2$$ Linear Heterodirectional Hyperbolic PDEs that Are Bidirectionally Coupled with Nonlinear ODEs ». Dans Advances in Distributed Parameter Systems, 117–42. Cham : Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-94766-8_6.
Texte intégralActes de conférences sur le sujet "PDEs with coupled fluxes"
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Banerjee, Abhishek, et Ameeya Kumar Nayak. « Assessment and Prediction of EOF Mixing in Binary Electrolytes ». Dans ASME 2017 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/fedsm2017-69524.
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A two dimensional simulation is made to analyse the mixing enhancement due to surface roughness and geometric modulation in a sufficiently long rectangular nano-channel filled with electrolyte solutions of different concentrations. Geometric modulation is made by mounting non-conducting rectangular blocks on the bottom wall of the channel. An overpotential patch is placed on the upper wall of each block to create surface heterogeneity. Based on a finite volume staggered grid approach, the flow characteristics and mixing efficiency are discussed by a complete numerical solution of coupled nonlinear set of PDEs involving Nernst-Planck equation for ion distribution, Navier-Stokes equation for velocity components and Maxwells equation for potential distribution. A linear pressure drop is observed above the overpotential region which creates a recirculating zone. Mixing efficiency is improved with increasing vortex strength which is enhanced by decreasing EDL (electric double layer) thickness and increasing overpotential patch strength.
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Hasan, Agus. « Disturbance attenuation of n + 1 coupled hyperbolic PDEs ». Dans 2014 IEEE 53rd Annual Conference on Decision and Control (CDC). IEEE, 2014. http://dx.doi.org/10.1109/cdc.2014.7039701.
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Xu, Qingqing, et Stevan Dubljevic. « Model predictive control of coupled hyperbolic PDEs and ODEs ». Dans 2016 IEEE 55th Conference on Decision and Control (CDC). IEEE, 2016. http://dx.doi.org/10.1109/cdc.2016.7799004.
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Ferrante, Francesco, et Andrea Cristofaro. « Boundary Observer Design for Coupled ODEs–Hyperbolic PDEs Systems ». Dans 2019 18th European Control Conference (ECC). IEEE, 2019. http://dx.doi.org/10.23919/ecc.2019.8795767.
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Olsen, Harold W. « Coupled Chemical and Liquid Fluxes in Earthen Materials ». Dans Symposium on Soil Behavior and Soft Ground Construction Honoring Charles C. "Chuck" Ladd. Reston, VA : American Society of Civil Engineers, 2003. http://dx.doi.org/10.1061/40659(2003)3.
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Gjerde, I., et M. Rognes. « A mixed framework for topological model reduction of coupled PDEs ». Dans 9th edition of the International Conference on Computational Methods for Coupled Problems in Science and Engineering. CIMNE, 2021. http://dx.doi.org/10.23967/coupled.2021.005.
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Anfinsen, Henrik, et Ole Morten Aamo. « Adaptive state feedback stabilization of n + 1 coupled linear hyperbolic PDEs ». Dans 2017 25th Mediterranean Conference on Control and Automation (MED). IEEE, 2017. http://dx.doi.org/10.1109/med.2017.7984234.
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Cassol, Guilherme Ozorio, et Stevan Dubljevic. « Robust Model Predictive Control for a system of coupled PDEs-ODEs ». Dans 2021 American Control Conference (ACC). IEEE, 2021. http://dx.doi.org/10.23919/acc50511.2021.9483403.
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Anfinsen, Henrik, et Ole Morten Aamo. « State estimation in hyperbolic PDEs coupled with an uncertain LTI system ». Dans 2017 American Control Conference (ACC). IEEE, 2017. http://dx.doi.org/10.23919/acc.2017.7963540.
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Aksikas, Ilyasse, Amir Alizadeh Moghadam et Fraser Forbes. « Optimal control of a time-varying system of coupled parabolic-hyperbolic PDEs ». Dans 2017 13th IEEE International Conference on Control & Automation (ICCA). IEEE, 2017. http://dx.doi.org/10.1109/icca.2017.8003083.
Texte intégralRapports d'organisations sur le sujet "PDEs with coupled fluxes"
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Andreas, Edgar L. The Impact of Sea Spray on Air-Sea Fluxes in Coupled Atmosphere-Ocean Models. Fort Belvoir, VA : Defense Technical Information Center, août 2001. http://dx.doi.org/10.21236/ada625427.
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Andreas, Edgar L. The Impact of Sea Spray on Air-Sea Fluxes in Coupled Atmosphere-Ocean Models. Fort Belvoir, VA : Defense Technical Information Center, septembre 2002. http://dx.doi.org/10.21236/ada627095.
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Andreas, Edgar L. The Impact of Sea Spray on Air-Sea Fluxes in Coupled Atmosphere-Ocean Models. Fort Belvoir, VA : Defense Technical Information Center, septembre 2002. http://dx.doi.org/10.21236/ada627375.
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Moum, James N. Subsurface Fluxes Beneath Large-Scale Convective Centers in the Indian Ocean : Coupled Air-Wave-Sea Processes in the Subtropics. Fort Belvoir, VA : Defense Technical Information Center, septembre 2012. http://dx.doi.org/10.21236/ada574114.
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Moum, James N. Subsurface Fluxes Beneath Large-Scale Convective Centers in the Indian Ocean : Coupled Air-Wave-Sea Processes in the Subtropics. Fort Belvoir, VA : Defense Technical Information Center, septembre 2013. http://dx.doi.org/10.21236/ada597978.
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Moum, James N. Subsurface Fluxes Beneath Large-Scale Convective Centers in the Indian Ocean ONR DRI : Coupled Air-Wave-Sea Processes in the Subtropics. Fort Belvoir, VA : Defense Technical Information Center, septembre 2010. http://dx.doi.org/10.21236/ada597816.
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Weinschenk, Craig, et Jack Regan. Analysis of Search and Rescue Tactics in Single-Story Single-Family Homes Part II : Kitchen and Living Room Fires. UL's Fire Safety Research Institute, mai 2022. http://dx.doi.org/10.54206/102376/zkxw6893.
Texte intégralRésumé :
Prior full-scale fire service research on the residential fireground has focused the impact of ventilation and suppression tactics on fire dynamics. This study builds upon prior research by conducting 10 experiments a purpose-built single-story, single-family residential structure to quantify the im- pact of how search and rescue tactics are coupled with ventilation and suppression actions and timing. Each fully furnished structure included four bedrooms, 2 bathrooms and an open-floor kitchen and living room. The structures were instrumented to quantify post-ignition toxic gas and thermal conditions. Temperature, velocity, and pressure were measured to evaluate the fire dynamics. Gas concentrations and heat fluxes were measured to quantify toxic and thermal exposures. Across this series of experiments, the impact of isolation of fire and non-fire compartments, the timing of search actions relative to suppression actions, and the influence of isolation, elevation, and path of travel during rescue were examined with respect to firefighter safety and occupant tenability. Similar to previous experiments in both purpose-built and acquired structure, the data showed that prior intervention locations lower in elevation and/or behind closed doors had lower toxic gas and thermal exposures compared to locations at higher elevations or locations that were not isolated. Lower elevations were also shown to have lower toxic gas and thermal exposures during the removal of occupants as part of rescue operations. For scenarios where search operations occurred prior to suppression, isolation of spaces from flow paths connected to the fire compartment was shown to be effective at reducing the thermal operating class for firefighters and the toxic and thermal exposure rates compared to spaces that were not isolated. Following isolation, exterior ventilation was found to further reduce the toxic gas and thermal exposures in the protected space. Suppression, from either interior and exterior positions, was effective at reducing the thermal operating class for searching firefighters and the rate of thermal exposure increase to occupants. Following suppression, additional exterior ventilation increased the rate at which gas concentrations returned to pre-ignition levels.
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Weinschenk, Craig. Analysis of Search and Rescue Tactics in Single-Story Single-Family Homes Part I : Bedroom Fires. UL's Fire Safety Research Institute, mai 2022. http://dx.doi.org/10.54206/102376/dptn2682.
Texte intégralRésumé :
Prior full-scale fire service research on the residential fireground has focused the impact of ventilation and suppression tactics on fire dynamics. This study builds upon prior research by conducting 11 experiments a purpose-built single-story, single-family residential structure to quantify the im- pact of how search and rescue tactics are coupled with ventilation and suppression actions and timing. Each fully furnished structure included four bedrooms, 2 bathrooms and an open-floor kitchen and living room. The structures were instrumented to quantify post-ignition toxic gas and thermal conditions. Temperature, velocity, and pressure were measured to evaluate the fire dynamics. Gas concentrations and heat fluxes were measured to quantify toxic and thermal exposures. Across this series of experiments, the impact of isolation of fire and non-fire compartments, the timing of search actions relative to suppression actions, and the influence of isolation, elevation, and path of travel during rescue were examined with respect to firefighter safety and occupant tenability. Similar to previous experiments in both purpose-built and acquired structure, the data showed that prior intervention locations lower in elevation and/or behind closed doors had lower toxic gas and thermal exposures compared to locations at higher elevations or locations that were not isolated. Lower elevations were also shown to have lower toxic gas and thermal exposures during the removal of occupants as part of rescue operations. For scenarios where search operations occurred prior to suppression, isolation of spaces from flow paths connected to the fire compartment was shown to be effective at reducing the thermal operating class for firefighters and the toxic and thermal exposure rates compared to spaces that were not isolated. Following isolation, exterior ventilation was found to further reduce the toxic gas and thermal exposures in the protected space. Suppression, from either interior and exterior positions, was effective at reducing the thermal operating class for searching firefighters and the rate of thermal exposure increase to occupants. Following suppression, additional exterior ventilation increased the rate at which gas concentrations returned to pre-ignition levels.
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Weinschenk, Craig, et Keith Stakes. Analysis of Search and Rescue Tactics in Single-Story Single-Family Homes Part III : Tactical Considerations. UL's Fire Safety Research Institute, mai 2022. http://dx.doi.org/10.54206/102376/xsla7995.
Texte intégralRésumé :
Prior full-scale fire service research on the residential fireground has focused the impact of ventilation and suppression tactics on fire dynamics. This study builds upon prior research by conducting 21 experiments in two identical purpose-built single-story, single-family residential structures to quantify the impact of how search and rescue tactics are coupled with ventilation and suppression actions and timing. Each fully furnished structure included four bedrooms, 2 bathrooms and an open-floor kitchen and living room. The structures were instrumented to quantify post-ignition toxic gas and thermal conditions. Temperature, velocity, and pressure were measured to evaluate the fire dynamics. Gas concentrations and heat fluxes were measured to quantify toxic and thermal exposures. Eleven experiments examined bedroom fires, eight examined kitchen fires, and two examined living room fires. Across this series of experiments, the impact of isolation of fire and non-fire compartments, the timing of search actions relative to suppression actions, and the influence of isolation, elevation, and path of travel during rescue were examined with respect to firefighter safety and occupant tenability. Similar to previous experiments in both purpose-built and acquired structure, the data showed that prior intervention locations lower in elevation and/or behind closed doors had lower toxic gas and thermal exposures compared to locations at higher elevations or locations that were not isolated. Lower elevations were also shown to have lower toxic gas and thermal exposures during the removal of occupants as part of rescue operations. For scenarios where search operations occurred prior to suppression, isolation of spaces from flow paths connected to the fire compartment was shown to be effective at reducing the thermal operating class for firefighters and the toxic and thermal exposure rates compared to spaces that were not isolated. Following isolation, exterior ventilation was found to further reduce the toxic gas and thermal exposures in the protected space. Suppression, from either interior and exterior positions, was effective at reducing the thermal operating class for searching firefighters and the rate of thermal exposure increase to occupants. Following suppression, additional exterior ventilation increased the rate at which gas concentrations returned to pre-ignition levels.