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Yu, Jin-Min. "A new three-parameter volume-cubic equation of state." Thesis, University of Ottawa (Canada), 1986. http://hdl.handle.net/10393/5531.
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Yaroson, Omolara. "Force field parameters from the SAFT equation of state for the molecular simulation of fused molecules." Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/25521.
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In this work, the analytical SAFT-γ Mie equation of state (EoS) is used in the efficient development of intermolecular force field parameters which can be used in direct molecular simulation for a range of fused dimer molecules. In its original formulation, the SAFT-γ Mie EoS only provides a direct link to the force field parameters for tangent models. A novel development here is to extend the application of the equation of state to obtain intermolecular potentials for fused models which more faithfully mimic realistic molecules. The proposed methodology consists of a two stage process: - An empirical mapping between the parameters of the theory and parameters used in simulation is first obtained by performing molecular dynamics simulations of the vapour-liquid equilibria for a wide range of homonuclear model dimer molecules with different bond lengths and Mie repulsive exponents. The simulation results are matched with those obtained using the theory for corresponding systems in order to determine the relationship between the parameters of the theory and the potential model. A methodology for obtaining unlike interaction parameters in heteronuclear dimer molecules is also developed and validated. - The mapping obtained is then used to translate the equation of state parameters of real molecules into a simulation force field with an explicit bond length. Force fields are obtained for a range of molecules with different levels of molecular resolution including atomistic models for molecular oxygen and nitrogen, united-atom models for ethane and perfluoroethane and more coarse-grained dimer models of propylbenzene and carbon dioxide. The properties obtained by simulation include vapour pressures, saturated liquid densities and interfacial tensions. This top-down methodology of obtaining force field parameters for computer simulation of fluids is much less computer and time intensive than the traditional methods. In the concluding chapter, a preliminary extension of the approach to trimers molecules is presented.
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Yahsi, Ugur. "Statistical thermodynamics of chain molecular fluids: Equation of state parameters for PVT scaling and their group contributions." Case Western Reserve University School of Graduate Studies / OhioLINK, 1994. http://rave.ohiolink.edu/etdc/view?acc_num=case1057868986.
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Johnson, Eleda. "The Elastic Behavior of Plagioclase Feldspar at High Pressure." Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/36450.
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Feldspars are one of the archetypical families of framework silicates. They not only comprise around 60% volumetrically of the Earthâ s crust, but are among some of the most structurally complicated minerals. Investigation into the structural behavior of various intermediate plagioclases at pressure has been undertaken with the intent of categorizing the elastic behavior with pressure across the solid solution series and establishing a conceptual model to characterize feldspar compression.
Complex behavior has been observed in the Equation of State for plagioclase feldspars in excess of 3 GPa, including an anomalous softening of ordered albite in excess of 8.4 GPa (Benusa et al 2005: Am Min 90:1115-1120). This softening was not observed in the EoS for the more intermediate plagioclase compositions containing between 20 and 40 mol% of end-member anorthite. The calculated elastic compliance tensor sums at room pressure show a general stiffening with increasing anorthite component, small elastic changes at the C-1 to I-1 transition, and a dominantly first-order response at the P-1 to I-1 transition near end-member anorthite.
The crystal structure of An37 plagioclase was determined by single-crystal X-ray diffraction. The compression mechanisms in An37 are similar to those in albite at lower pressures. The softening in albite at higher pressures is therefore attributed to the structural shearing in albite that is absent in An37 plagioclase up to 9.5 GPa.Master of Science
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Nagrale, Sumedh Sopan. "Two Player Zero Sum Multi-Stage Game Analysis Using Coevolutionary Algorithm." Wright State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=wright1557144260873961.
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King, Nathan H. "Vapor-liquid Equilibrium of Polymer Solutions During Thermal Decomposition of Rigid Foams." Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2538.pdf.
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Dittrich, Petr. "Odhad Letových Parametrů Malého Letounu." Doctoral thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2017. http://www.nusl.cz/ntk/nusl-412582.
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Tato práce je zaměřena na odhad letových parametrů malého letounu, konkrétně letounu Evektor SportStar RTC. Pro odhad letových parametrů jsou použity metody "Equation Error Method", "Output Error Method" a metody rekurzivních nejmenších čtverců. Práce je zaměřena na zkoumání charakteristik aerodynamických parametrů podélného pohybu a ověření, zda takto odhadnuté letové parametry odpovídají naměřeným datům a tudíž vytvářejí předpoklad pro realizaci dostatečně přesného modelu letadla. Odhadnuté letové parametry jsou dále porovnávány s a-priorními hodnotami získanými s využitím programů Tornado, AVL a softwarovéverze sbírky Datcom. Rozdíly mezi a-priorními hodnotami a odhadnutými letovými paramatery jsou porovnány s korekcemi publikovanými pro subsonické letové podmínky modelu letounu F-18 Hornet.
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Bright, Andrew G. "Mechanistic Insights into the Stabilisation of Biopharmaceuticals using Glycine Derivatives. The Effect of Glycine Derivatives on the Crystallisation, Physical Properties and Behaviour of Commonly used Excipients to Stabilise Antigens, Adjuvants and Proteins in the Solid State." Thesis, University of Bradford, 2015. http://hdl.handle.net/10454/15943.
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This dissertation has focused on studying the effect of four glycine derivatives on the solid state properties of mannitol, glycine, and sucrose when freeze dried into blended mixtures. The primary goal was to assess their value for use in the stabilisation of vaccines in the solid state, by examining key physical and chemical characteristics, which have been documented to be beneficial to the stabilisation of biopharmaceutical formulations. The novel excipients; dimethyl glycine, and trimethyl glycine, were shown to retard the crystallisation and increase the overall glass transition temperature, of mannitol, when freeze dried as evidenced by DSC and Powder X-ray diffraction. Mannitol’s glass transition temperature increased from 100C to 12.650C and 13.610C when mixed with methyl-glycine and dimethyl glycine respectively. The glycine derivatives did not show the same effect on sucrose which remained amorphous regardless of the concentration of the other excipient. The different behaviour with the sucrose system was thought to be due to relatively high glass transition temperature of sucrose. Conversely glycine remained highly crystalline due it’s relatively low glass transition temperature. The novel excipient formulations were also assessed for their effect on the aggregation of the adjuvant aluminium hydroxide when freeze dried by Dynamic Light Scattering (DLS).The formulations containing the glycine derivatives all caused a decrease in the aggregation size of the adjuvant from ~26 μm, to 185 nm in the presence of methyl glycine. The effects of lysozyme and viral antigen on the adjuvants were also examined showing that the addition of the virus did not affect the size of the aggregates formed, however lysozyme showed significant decreases in the aggregates formed. Examination of the freezing method were also made showing that faster freezing rates produced smaller aggregates of the adjuvant. When investigating the rate at which the excipients lost water during secondary drying there was evidence of the formation of hydrates of glycine, trimethyl glycine, and mannitol has shown that the glycine derivatives have attributes which would be beneficial in stabilising vaccines in the solid state when freeze dried.
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Dutra, Dimas Abreu. "Maximum a posteriori joint state path and parameter estimation in stochastic differential equations." Universidade Federal de Minas Gerais, 2014. http://hdl.handle.net/1843/BUOS-9S3H9D.
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A wide variety of phenomena of engineering and scientific interest are of a continuous-time nature and can be modeled by stochastic differential equations (SDEs), which represent the evolution of the uncertainty in the states of a system. For systems of this class, some parameters of the SDE might be unknown and the measured data often includes noise, so state and parameter estimators are needed to perform inference and further analysis using the system state path. One such application is the flight testing of aircraft, in which flight path reconstruction or some other data smoothing technique is used before proceeding to the aerodynamic analysis or system identification. The distributions of SDEs which are nonlinear or subject to non-Gaussian measurement noise do not admit tractable analytic expressions, so state and parameter estimators for these systems are often approximations based on heuristics, such as the extended and unscented Kalman smoothers, or the prediction error method using nonlinear Kalman filters. However, the Onsager Machlup functional can be used to obtain fictitious densities for the parameters and state-paths of SDEs with analytic expressions. In this thesis, we provide a unified theoretical framework for maximum a posteriori (MAP) estimation of general random variables, possibly infinitedimensional, and show how the OnsagerMachlup functional can be used to construct the joint MAP state-path and parameter estimator for SDEs. We also prove that the minimum energy estimator, which is often thought to be the MAP state-path estimator, actually gives the state paths associated to the MAP noise paths. Furthermore, we prove that the discretized MAP state-path and parameter estimators, which have emerged recently as powerful alternatives to nonlinear Kalman smoothers, converge hypographically as the discretization step vanishes. Their hypographical limit, however, is the MAP estimator for SDEs when the trapezoidal discretization is used and the minimum energy estimator when the Euler discretization is used, associating different interpretations to each discretized estimate. Example applications of the proposed estimators are also shown, with both simulated and experimental data. The MAP and minimum energy estimators are compared with each other and with other popular alternatives.Uma grande variedade de fenômenos de interesse para engenharia e ciência são a tempo contínuo por natureza e podem ser modelados por equações diferenciais estocásticas (EDEs), que representam a evolução da incerteza nos estados do sistema. Para sistemas dessa classe, alguns parâmetros da EDE podem ser desconhecidos e os dados coletados frequentemente incluem ruídos, de modo que estimatores de esstados e parâmetros são necessários para realizar inferência e análises adicionais usando a trajetória dos estados do sistema. Uma dessas aplicações é em ensaios em voo de aeronaves, para os quais reconstrução de trajetória de voo ou outras técnicas de suavização são utilizadas antes de se proceder para análise aerodinâmica ou identificação de sistemas. As distribuições de EDEs não lineares ou sujeitas a ruído de medição não Gaussiano não admitem expressões analíticas utilizáveis, o que leva a estimadores de estados e parâmetros para esses sistemas a basearem-se em heurísticas como os suavizadores de Kalman estendido e unscented, ou o método de predição de erro utilizando filtros de Kalman não lineares. No entanto, o funcional de OnsagerMachlup pode ser utilizado para obter densidades fictícias conjuntas para trajetórias de estado e parâmetros de EDEs com expressões analíticas. Nesta tese, um arcabouço teórico unificado é desenvolvido para estimação máxima a posteriori (MAP) de variáveis aleatórias genéricas, possivelmente infinito-dimensionais, e é mostrado como o funcional de OnsagerMachlup pode ser utilizado para a construção do estimador MAP conjunto de trajetórias de estado e parâmetros de EDEs. Também é provado que o estimador de mínima energia, comumente confundido com com o estimador de MAP, obtém as trajetórias de estado associadas às trajetórias de ruído MAP. Além disso, é provado que os estimadores conjuntos de trajetória de estados e parâmetros MAP discretizados, que emergiram recentemente como alternativas poderosas para os estimadores de Kalman não lineares, convergem hipograficamente à medida que o passo de discretização diminue. O seu limite hipográfico, no entanto, é o estimador MAP para EDEs quando a discretização trapezoidal é utilizada e o estimador de mínima energia quando a discretização de Euler é utilizada, associando interpretações diferentes a cada estimativa discretizada. Exemplos de aplicações dos estimadores propostos são apresentadas com dados simulados e experimentais, nas quais os estimadores MAP e de mínima energia são comparados entre si e com alternativas mais bem sedimentadas.
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Melia, F. "The cosmic equation of state." Springer Verlag, 2014. http://hdl.handle.net/10150/614766.
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The cosmic spacetime is often described in terms of the Friedmann-Robertson-Walker
(FRW) metric, though the adoption of this elegant and convenient solution to Einstein's
equations does not tell us much about the equation of state, $p=w\rho$, in terms of the
total energy density $\rho$ and pressure $p$ of the cosmic fluid. $\Lambda$CDM and
the $R_{\rm h}=ct$ Universe are both FRW cosmologies that partition $\rho$ into
(at least) three components, matter $\rho_{\rm m}$, radiation $\rho_{\rm r}$, and a
poorly understood dark energy $\rho_{\rm de}$, though the latter goes one step
further by also invoking the constraint $w=-1/3$. This condition is apparently required
by the simultaneous application of the Cosmological principle and Weyl's postulate.
Model selection tools in one-on-one comparisons between these two cosmologies favor
$R_{\rm h}=ct$, indicating that its likelihood of being correct is $\sim 90\%$
versus only $\sim 10\%$ for $\Lambda$CDM. Nonetheless, the predictions of
$\Lambda$CDM often come quite close to those of $R_{\rm h}=ct$, suggesting
that its parameters are optimized to mimic the $w=-1/3$ equation-of-state.
In this paper, we explore this hypothesis quantitatively and demonstrate
that the equation of state in $R_{\rm h}=ct$ helps us to understand why the
optimized fraction $\Omega_{\rm m}\equiv \rho_m/\rho$ in $\Lambda$CDM
must be $\sim 0.27$, an otherwise seemingly random variable. We show that
when one forces $\Lambda$CDM to satisfy the equation of state
$w=(\rho_{\rm r}/3-\rho_{\rm de})/\rho$, the value of the Hubble radius today,
$c/H_0$, can equal its measured value $ct_0$ only with $\Omega_{\rm m}\sim0.27$
when the equation-of-state for dark energy is $w_{\rm de}=-1$. (We also show, however,
that the inferred values of $\Omega_{\rm m}$ and $w_{\rm de}$ change in a correlated fashion
if dark energy is not a cosmological constant, so that $w_{\rm de}\not= -1$.)
This peculiar value of $\Omega_{\rm m}$ therefore appears to be a direct
consequence of trying to fit the data with the equation of state
$w=(\rho_{\rm r}/3-\rho_{\rm de})/\rho$ in a Universe whose principal
constraint is instead $R_{\rm h}=ct$ or, equivalently, $w=-1/3$.
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Ramirez, Edgardo II. "Finite element methods for parameter identification problem of linear and nonlinear steady-state diffusion equations." Diss., Virginia Tech, 1997. http://hdl.handle.net/10919/28173.
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We study a parameter identification problem for the steady state
diffusion equations. In this thesis, we transform this
identification problem into a minimization problem by considering an
appropriate cost functional and propose a finite element method for the
identification of the parameter for the linear and nonlinear partial
differential equation.
The cost functional involves the classical
output least square term, a term approximating the
derivative of the piezometric head u(x), an equation error term
plus some regularization terms,
which happen to be a norm or a semi-norm of the variables in the cost functional in an
appropriate Sobolev space. The existence and uniqueness of the
minimizer for the cost functional is proved.
Error estimates in a weighted
H-1-norm, L2-norm and L1-norm for the numerical solution are derived.
Numerical examples
will be given to show features of this numerical method.Ph. D.
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Privat, Romain. "Développement du modèle PPR78 pour décrire, comprendre et prédire les diagrammes de phases hautes et basses pressions des systèmes binaires et des fluides pétroliers." Thesis, Vandoeuvre-les-Nancy, INPL, 2008. http://www.theses.fr/2008INPL090N/document.
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Le développement d'un modèle thermodynamique prédictif PPR78, basé sur le concept de contributions de groupes, a été entrepris afin de pouvoir prédire avec précision, le comportement des fluides pétroliers. PPR78 utilise l’équation d’état de Peng et Robinson et les règles de mélange de Van der Waals avec un seul coefficient d’interactions binaires kij, dépendant de la température. Cette approche est rigoureusement équivalente à l’utilisation de règles de mélange à compacité constante avec un modèle d’énergie de Gibbs molaire d’excès, gE, de type Van Laar. Pour développer ce modèle, une étude approfondie des équilibres entre phases fluides des systèmes binaires a été réalisée en deux temps. Dans un premier, une étude phénoménologique permet d'éclairer sous un jour nouveau la classification proposée par Van Konynenburg et Scott qui décrit qualitativement les comportements de ces systèmes. Dans un second temps, quelques principes généraux de calcul des diagrammes d’équilibre de phases isothermes, isobares et globaux sont exposés. L’étude de la stabilité thermodynamique globale occupe une place essentielle au sein de ces calculs. Une fois ces étapes préliminaires franchies, l’extension du modèle aux groupes CO2, N2, H2S et sulfhydryle est réalisée. Une bonne précision du modèle est obtenue pour décrire les systèmes binaires impliquant ces quatre groupes. Enfin, le comportement des fluides pétroliers est souvent prédit avec une précision de l'ordre de l'erreur expérimentale par PPR78A predictive thermodynamic model, based on the group contribution concept, and called PPR78, has been developed in order to be able to predict, with high accuracy, the behaviour of petroleum fluids. PPR78 uses the Peng-Robinson equation of state with Van der Waals mixing rules and a temperature dependent binary interaction parameter kij. This method is the equivalent to the constant packing fraction mixing rules with a Van Laar excess Gibbs energy model (gE). To develop the model, an in-depth study on binary systems fluid phase equilibria, was carried out. It was divided into two parts. Firstly, a phenomenological study made a reappraisal of the Van Konynenburg and Scott classification possible. Secondly, some general rules for the calculation of isothermal, isobaric and global phase equilibrium diagrams were demonstrated. It is important to note that the study of the global thermodynamic stability is essential in the calculations. Once these preliminary steps were realized, the extension of the model to the CO2, N2, H2S and sulfhydryl groups was performed. The fluid phase behaviour of binary systems involving these four groups was accurately calculated by the PPR78 model. Finally, the properties of petroleum fluids were predicted by PPR78 with an accuracy close to the experimental uncertainty
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Qian, Junwei. "Développement du modèle E-PPR78 pour prédire les équilibres de phases et les grandeurs de mélange de systèmes complexes d’intérêt pétrolier sur de larges gammes de températures et de pressions." Thesis, Vandoeuvre-les-Nancy, INPL, 2011. http://www.theses.fr/2011INPL105N/document.
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Nous avons développé un modèle prédictif, utilisant le principe de contribution de groupes, pour prédire avec précision, le comportement des fluides pétroliers. Ce modèle baptisé PPR78 utilise l’équation d’état de Peng et Robinson et des règles de mélange de type Van der Waals avec un coefficient d’interaction binaire kij, dépendant de la température. De telles règles de mélange sont équivalentes à celles obtenues en combinant à compacité constante une fonction d’excès de type Van Laar et une équation d’état cubique.La première partie de cette étude a consisté à étendre le domaine d’application du modèle PPR78 aux systèmes contenant de l’eau, des alcènes et de l’hydrogène, en définissant six nouveaux groupes élémentaires. Une bonne précision du modèle est obtenue pour décrire les équilibres de phases de systèmes binaires impliquant ces constituants, notamment pour les systèmes présentant des diagrammes de phases de Type I et de Type II. Dans la deuxième partie l’ensemble des paramètres de groupes ont été réajustés, non seulement sur des données d’équilibres de phases mais également sur des données de grandeur de mélange. L’avantage de ce nouveau modèle E-PPR78 est qu’il permet de restituer les équilibres de phases avec une précision équivalente au modèle original et qu’il conduit à une très nette amélioration de la prédiction des enthalpies d’excès et des capacités calorifiques d’excèsWe have developed a predictive model, by means of a group contribution method, in order to predict with accuracy, the behavior of petroleum fluids. The model called PPR78 uses the Peng-Robinson equation of state and Van der Waals-type mixing rules with a temperature dependent binary interaction parameter kij. Such mixing rules are identical to those obtained by combining at constant packing fraction, a Van Laar-type excess function and a cubic equation of state.The first part of this study consisted in extending the application of the model PPR78 to systems containing water, alkenes and hydrogen, by defining six new elementary groups. The phase equilibria of binary systems involving these components are accurately described by the model, especially for the phase diagrams of Type I and Type II. In the second part, all the group parameters of the original model were re-fitted by using the phase equilibrium data, as well as the mixing property data. The advantage of this new model E-PPR78 is that it is capable to correlate the phase equilibria with an accuracy which is equivalent to the original model and it produces a very clear improvement in the prediction of excess enthalpies and excess heat capacities
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Atilhan, Mert. "A new cubic equation of state." Thesis, Texas A&M University, 2004. http://hdl.handle.net/1969.1/352.
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Thermodynamic properties are essential for the design of chemical processes, and they are most useful in the form of an equation of state (EOS). The motivating force of this work is the need for accurate prediction of the phase behavior and thermophysical properties of natural gas for practical engineering applications. This thesis presents a new cubic EOS for pure argon. In this work, a theoretically based EOS represents the PVT behavior of pure fluids. The new equation has its basis in the improved Most General Cubic Equation of State theory and forecasts the behavior of pure molecules over a broad range of fluid densities at both high and low pressures in both single and multiphase regions. With the new EOS, it is possible to make accurate estimations for saturated densities and vapor pressures. The density dependence of the equation results from fitting isotherms of test substances while reproducing the critical point, and enforcing the critical point criteria. The EOS includes analytical functions to fit the calculated temperature dependence of the new EOS parameters.
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陳柏緯 and Pak-wai Chan. "Equation of state of nuclear matter." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1994. http://hub.hku.hk/bib/B31211215.
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Vitu, Stéphane. "Développement d'une méthode de contributions de groupes pour le calcul du coefficient d'interaction binaire de l'équation d'état de Peng-Robinson et mesures d'équilibres liquide-vapeur de systèmes contenant du CO2." Thesis, Vandoeuvre-les-Nancy, INPL, 2007. http://www.theses.fr/2007INPL080N/document.
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Nous avons développé une méthode de contributions de groupes permettant d'estimer, en fonction de la température, le coefficient d'interaction binaire (kij) de l'équation d'état de Peng Robinson. Notre approche rend cette équation d'état prédictive. Douze groupes sont définis et il est possible d'estimer les kij pour n'importe quel mélange renfermant des alcanes, des aromatiques, des naphtènes et du CO2. Les diagrammes de phase et lieux des points critiques des systèmes binaires sont bien prédits par le modèle baptisé PPR78 (Predictive 1978, Peng Robinson equation of state). Ce modèle permet également de traiter efficacement les mélanges multiconstituants comme les pétroles bruts et les gaz naturels. A l'aide d'une cellule haute pression, des mesures d'équilibres liquide - vapeur ont été réalisées pour la première fois sur deux systèmes binaires : CO2 méthylcyclopentane et CO2 isopropylcyclohexane. Des mesures ont également été faites sur un mélange renfermant du CO2 et cinq hydrocarburesA group contribution method allowing the estimation of the temperature dependent binary interaction parameter (kij) for the Peng Robinson equation of state is proposed. Doing so, a new predictive thermodynamic model is born. Twelve groups are defined and it is now possible to estimate the kij for any mixture containing alkanes, aromatics, naphthenes and CO2, whatever the temperature. The model, called PPR78 (Predictive 1978, Peng Robinson equation of state), gives a good description of the phase diagrams and critical locus of binary systems. This predictive model can be successfully employed for the simulation of many mixtures such as natural gases and petroleum fluids. Using a high pressure visual cell, vapor liquid equilibria measurements were made for two binary systems: CO2 methylcyclopentane and CO2 isopropylcyclohexane. For these two systems, no literature data were available. Finally, we measured bubble and dew points on a five component hydrocarbon mixture in the presence of CO2
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Kedge, Christopher J. "A new non-cubic equation of state." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0017/MQ49698.pdf.
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Ghobadi, Fomeshi Ahmadreza. "Toward an Equation of State for Biosurfactants." University of Akron / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1405344829.
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Estela-Uribe, Jorge Francisco. "Equation of state for natural gas systems." Thesis, Imperial College London, 1999. http://hdl.handle.net/10044/1/11230.
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Li, Hailong. "Thermodynamic Properties of CO2 Mixtures and Their Applications in Advanced Power Cycles with CO2 Capture Processes." Doctoral thesis, KTH, Energiprocesser, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-9109.
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The thermodynamic properties of CO2-mixtures are essential for the design and operation of CO2 Capture and Storage (CCS) systems. A better understanding of the thermodynamic properties of CO2 mixtures could provide a scientific basis to define a proper guideline of CO2 purity and impure components for the CCS processes according to technical, safety and environmental requirements. However the available accurate experimental data cannot cover the whole operation conditions of CCS processes. In order to overcome the shortage of experimental data, theoretical estimation and modelling are used as a supplemental approach. In this thesis, the available experimental data on the thermodynamic properties of CO2 mixtures were first collected, and their applicability and gaps for theoretical model verification and calibration were also determined according to the required thermodynamic properties and operation conditions of CCS. Then in order to provide recommendations concerning calculation methods for engineering design of CCS, totally eight equations of state (EOS) were evaluated for the calculations about vapour liquid equilibrium (VLE) and density of CO2-mixtures, including N2, O2, SO2, Ar, H2S and CH4. With the identified equations of state, the preliminary assessment of impurity impacts was further conducted regarding the thermodynamic properties of CO2-mixtures and different processes involved in CCS system. Results show that the increment of the mole fraction of non-condensable gases would make purification, compression and condensation more difficult. Comparatively N2 can be separated more easily from the CO2-mixtures than O2 and Ar. And a lower CO2 recovery rate is expected for the physical separation of CO2/N2 under the same separation conditions. In addition, the evaluations about the acceptable concentration of non-condensable impurities show that the transport conditions in vessels are more sensitive to the non-condensable impurities and it requires very low concentration of non-condensable impurities in order to avoid two-phase problems. Meanwhile, the performances of evaporative gas turbine integrated with different CO2 capture technologies were investigated from both technical and economical aspects. It is concluded that the evaporative gas turbine (EvGT) cycle with chemical absorption capture has a smaller penalty on electrical efficiency, while a lower CO2 capture ratio than the EvGT cycle with O2/CO2 recycle combustion capture. Therefore, although EvGT + chemical absorption has a higher annual cost, it has a lower cost of electricity because of its higher efficiency. However considering its lower CO2 capture ratio, EvGT + chemical absorption has a higher cost to avoid 1 ton CO2. In addition the efficiency of EvGT + chemical absorption can be increased by optimizing Water/Air ratio, increasing the operating pressure of stripper and adding a flue gas condenser condensing out the excessive water.QC 20100819
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Baillot, d'Étivaux Nicolas. "Équation d’état de la matière à densité supranucléaire et application à l’émission thermique des étoiles compactes." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1168/document.
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Cette thèse porte sur la modélisation théorique de l'équation d’état (EE) décrivant la matière nucléaire présente dans le coeur des étoiles à neutrons (EN), sous l'hypothèse qu'aucune transition de phase ne s'y produise. Nous utilisons un méta-modèle permettant i) d’incorporer directement les connaissances en physique nucléaire sous la forme de paramètres empiriques tels que la densité de saturation nucléaire, l’incompressibilité, l’énergie de symétrie; ii) de reproduire la plupart des modèles nucléoniques existants; et iii) d’explorer les régions inconnues à haute densité de façon la plus large possible. Pour chaque EE, nous déterminons un ensemble de solutions pour la masse et le rayon des EN, et nous effectuons une première sélection des EE compatibles avec la stabilité et la causalité de la matière nucléaire, ainsi que la masse maximale connues des EN. Nous confrontons ensuite ces EE aux observations d’émission thermique dans la gamme des rayons-X pour 7 EN soigneusement choisies. Pour la première fois, la modélisation théorique des EE est directement introduite dans l’analyse des données. Nous utilisons les dernières mesures effectuées par GAIA II pour fixer la distance des EN. Les paramètres du modèle d’émission thermique et de l’EE sont déterminés selon une méthode Bayésienne basée sur un algorithme Monte-Carlo par Chaîne de Markov. Nous déterminons ainsi la température de surface, la masse et le rayon des EN, ainsi que sur la valeur de certains paramètres empiriques tels que la dépendance en densité de l'énergie de symétrie (Lsym), la contribution isovectorielle au module d’incompressibilité (Ksym) ou encore le paramètre de distorsion isoscalaire (Qsat)This thesis concerns theoretical modeling of the equation of state (EoS) describing nuclear matter in the core of neutron stars (NS), under the hypothesis that no phase transition occurs. We use a meta-model which is able to i) directly incorporate nuclear physics knowledge on the form of empirical parameters such as the nuclear saturation density, the incompressibility or the symmetry energy; ii) reproduce most of the existing models; iii) explore new behaviors at high densities in a very flexible way. For each EoS, we determine a set of solutions for the masses and radii of NS, and we make a first selection of the EoS that are compatible with the stability and causality constraints, as well as the maximum observed mass of NS. Then we confront these EoS to observational data coming from thermal emission in the soft X-ray domain, for 7 NS carefully chosen. For the first time, the theoretical modeling of the EoS is directly implemented in the data analysis. We use the recent measurments of GAIA II to constrain the distance to the NS. The parameters of the modeling of thermal emission as well as the empirical parameters entering in the EoS are determined by Bayesian methods using a Monte-Carlo by Morkov Chain algorithm. Therefore, we determine the surface effective tempreature, the masses and radii of NS, as well as some empirical nuclear parameters such as the density dependance of the symmetry energy (Lsym), the isovector incompressibility (Ksym), or the isoscalar squewness (Qsat)
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Paz, Sidrak Jos? da. "Infer?ncia do ponto de orvalho em amostras de g?s natural processado." Universidade Federal do Rio Grande do Norte, 2011. http://repositorio.ufrn.br:8080/jspui/handle/123456789/15819.
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This dissertation aims to assess the representativeness of the manual chilled mirror analyzer (model II Chanscope 13-1200-CN-2) used for the determination of condensed hydrocarbons of natural gas compared to the indirect methods, based on thermodynamic models equation of state. Additionally, it has been implemented in this study a model for calculating the dew point of natural gas. The proposed model is a modification of the equation of state of Peng-Robinson admits that the groups contribution as a strategy to calculate the binary interaction parameters kij (T) temperature dependence. Experimental data of the work of Brown et al. (2007) were used to compare the responses of the dew point of natural gas with thermodynamic models contained in the UniSim process simulator and the methodology implemented in this study. Then two natural gas compositions were studied, the first being a standard gas mixture gravimetrically synthesized and, second, a mixture of processed natural gas. These experimental data were also compared with the results presented by UniSim process simulator and the thermodynamic model implemented. However, data from the manual analysis results indicated significant differences in temperature, these differences were attributed to the formation of dew point of water, as we observed the appearance of moisture on the mirror surface cooling equipment
O presente trabalho de disserta??o tem por objetivo avaliar a representatividade do analisador manual de espelho refrigerado (Chanscope II modelo 13-1200-C-N-2) usado para a determina??o do condensado de hidrocarbonetos de g?s natural frente aos m?todos indiretos, fundamentados em modelos termodin?micos de equa??o de estado. Adicionalmente, tem sido implementado neste estudo um modelo para c?lculo do ponto de orvalho de g?s natural. O modelo proposto constitui uma modifica??o na equa??o de estado de Peng-Robinson que admite a contribui??o de grupos como estrat?gia para calcular os par?metros de intera??o bin?ria kij(T) com depend?ncia da temperatura. Dados experimentais do trabalho de Brown et al. (2007) foram utilizados para comparar as respostas de ponto de orvalho do g?s natural com os modelos termodin?micos contidos no simulador de processo UniSim e com a metodologia implementada neste estudo. Em seguida, duas composi??es de g?s natural foram estudadas, sendo a primeira uma mistura padr?o de g?s sintetizada gravimetricamente e, a segunda, uma mistura de g?s natural processado. Tais dados experimentais foram tamb?m comparados com os resultados apresentados pelo simulador de processo UniSim e pelo modelo termodin?mico implementado. No entanto, os dados do analisador manual indicaram diferen?as significativas nos resultados de temperaturas, sendo estas diferen?as atribu?das ? forma??o de ponto de orvalho de ?gua, j? que foi observado o aparecimento de umidade sobre a superf?cie do espelho refrigerado do equipamento
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Mincarelli, Diego. "Parameters and state estimation for switched systems." Thesis, Lille 1, 2013. http://www.theses.fr/2013LIL10146.
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Les systèmes hybrides sont largement étudiés pour modéliser des systèmes issus de différents domaines de l’ingénierie. De façon générale, l’évolution des systèmes hybrides est caractérisée par la combinaison de dynamiques continues et d’événements discrets. Les exemples de systèmes hybrides incluent les réseaux, les systèmes multi-agents, certains dispositifs mécaniques ou les convertisseurs de puissance. Les recherches sur les systèmes hybrides couvrent tous les champs de la théorie du contrôle tels que l'analyse de la stabilité ou les problèmes de commande et d'observation. Dans le contexte des systèmes à commutation, qui sont une classe particulière de systèmes hybrides, cette thèse vise à étudier le problème lié à l'extraction d'informations sur les paramètres et l'état du système à partir des mesures disponibles. Ceci peut être motivé par divers objectifs: la modélisation, la commande, la détection de fautes ainsi que leur identification pour la sécurité de systèmes. Pour ces raisons, l'identification et l'observation sont au cœur des problèmes de décision et contrôle. La première partie de la thèse est consacrée à étendre l'applicabilité des méthodes basées sur l'algèbre pour l'estimation de paramètre constant en ligne, développées par l'équipe projet INRIA - Non-A, pour le cas des systèmes à paramètres constants par morceaux. À cette fin, une procédure pour l'estimation des paramètres et des temps de commutation est développée dans le cadre des systèmes à commutation. Une telle approche permet une estimation algébrique simultanée des paramètres et instants de changement. La nouveauté et l'efficacité des algorithmes proposées pour l'identification se situent principalement dans leur nature non asymptotique. La deuxième partie de la thèse aborde le problème de construction d'observateur pour estimer l'état discret ainsi que l'état continu des systèmes à commutation. Étant donné que les systèmes hybrides sont régis par des dynamiques à la fois continues et discrètes, la difficulté du problème d’observation s’en trouve augmentée. Par exemple, il faut gérer les discontinuités inhérentes au système, les estimées désirées doivent être obtenues relativement rapidement (entre deux commutations ou événements discrets). Ainsi, nous proposons un observateur basé sur des techniques en temps fini (modes glissants) pour la reconstruction de l'état continu et du signal de commutation (état discret) en temps fini. Enfin, nous traitons une autre classe de systèmes à commutation où les paramètres, dans chaque sous-système, sont variables dans le temps. Pour ce type de modèles, appelés switched linear parameter varying systems, nous construisons un estimateur de l'état discret en utilisant des techniques d'identification de paramètresHybrid systems have been widely studied in the literature and became a powerful tool for modeling systems coming from many engineering fields. A common definition of hybrid systems is a combination of both continuous-time and discrete event systems. Examples of hybrid systems include networks, multi-agent systems, mechanical devices, robot path planning, biological systems. Researches on hybrid systems cover all fields of control theory such as stability analysis, control and observation problems or supervision. In the context of switched systems, which is a particular class of hybrid systems, this thesis aims at studying the problem related to extracting information about the system parameters and the state from the knowledge of the output.This study is motivated by various purposes: modeling, monitoring, fault detection and identification for the systems safety, output feedback control. For those reasons,the identification and the observation are at the core of decision and control problems.The first part of the thesis is devoted to extend the applicability of the algebra-based methods for on-line constant parameter estimation, developed by INRIA – Non-A project-team, to the case of systems with piecewise constant parameters. To this end, a procedure for the estimation of the parameters and the switching times is developed in the framework of switched systems.Such an approach enables a simultaneous algebraic estimation of both parameters and change time instants. The novelty and efficiency of the proposed identification algorithms mainly lie in their non asymptotic nature. The second part of the thesis addresses the problem of observer design for estimating the discrete and the continuous state of switched systems.Since switched systems contain a family of continuous-time systems and discrete-event systems, the evolution of their dynamics is naturally non-smooth, and this increases the difficulties to solve the observation problem. For instance, the estimates have to be provided before the next switch takes place. Thus, we propose an observer based on finite-time techniques (sliding-mode based) for the reconstruction of the continuous states and the switching signal (discrete state) in finite-time. Finally, we deal with another class of switched systems where the parameters, in each subsystem, are time-varying. For this kind of models, called switched linear parameter varying systems, we design an estimator for reconstructing the discrete state, by using parameter identification techniques
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Colin-Lalu, Pierre. "Étude de l'équation d'état des matériaux ablateurs des capsules du Laser Mégajoule." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLX054/document.
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Cette thèse s’inscrit dans le cadre de recherches menées sur la fusion par confinement inertiel (FCI). En particulier, l’étude proposée ici s’est concentrée sur les équations d’état tabulées de deux matériaux ablateurs synthétisés sur les capsules du Laser Mégajoule. Le but est alors de tester la modélisation théorique implémentée dans ces tables. Nous avons concentré notre étude sur un domaine restreint du diagramme de phase caractérisé par des pressions de quelques mégabars et de températures de quelques électronvolts qui peut être atteint sur des installations laser de tailles moyennes.Pour ce faire, nous nous sommes basés sur le modèle QEOS, car il est simple d’utilisation, paramétrable et donc facilement modifiable.Nous avons ensuite appliqué les méthodes de la dynamique moléculaire quantique pour générer la courbe froide et les courbes d’Hugoniot des deux matériaux étudiés. Ces calculs ont notamment mis en avant l’influence de la dissociation chimique sur la forme de ces courbes. Une comparaison avec le modèle QEOS a montré un écart important sur l’Hugoniot. Une modification de ce modèle, à travers le coefficient de Grüneisen, nous a ensuite permis de restituer les effets observés et d’étudier leurs impacts sur la chronométrie des chocs dans une capsule de FCI.Parallèlement à cette étude numérique, nous avons mesuré des états thermodynamiques le long de l’Hugoniot lors de trois campagnes sur les installations laser LULI2000 et GEKKO XII. L’utilisation de diagnostics VISAR et d’un diagnostic d’émission propre, nous a alors permis de sonder la matière sous choc. En outre, les données expérimentales ont confirmé les précédents résultats.En outre, cette étude a été réalisée sur deux matériaux ablateurs différents parmi lesquels on distingue le polymère non dopé CHO et le polymère dopé au silicium CHOSi. Elle montre un comportement universel de ces matériaux le long de l’HugoniotThis PhD thesis enters the field of inertial confinement fusion studies. In particular, it focuses on the equation of state tables of ablator materials synthetized on LMJ capsules. This work is indeed aims at improving the theoretical models introduced into the equation of state tables. We focused in the Mbar-eV pressure-temperature range because it can be access on kJ-scale laser facilities.In order to achieve this, we used the QEOS model, which is simple to use, configurable, and easily modifiable.First, quantum molecular dynamics (QMD) simulations were performed to generate cold compression curve as well as shock compression curves along the principal Hugoniot. Simulations were compared to QEOS model and showed that atomic bond dissociation has an effect on the compressibility. Results from these simulations are then used to parametrize the Grüneisen parameter in order to generate a tabulated equation of state that includes dissociation. It allowed us to show its influence on shock timing in a hydrodynamic simulation.Second, thermodynamic states along the Hugoniot were measured during three experimental campaigns upon the LULI2000 and GEKKO XII laser facilities. Experimental data confirm QMD simulations.This study was performed on two ablator materials which are an undoped polymer CHO, and a silicon-doped polymer CHOSi. Results showed universal shock compression properties
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Satyro, Marco Aurelio. "An equation of state based on significant structure theory." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq20770.pdf.
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Davidson, A. N. "Order parameters in liquid crystals." Thesis, University of Greenwich, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234287.
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Vlk, Jan. "Návrh a evaluace moderních systémů řízení letu." Doctoral thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2021. http://www.nusl.cz/ntk/nusl-445472.
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Tato práce je zaměřena na výzkum moderních metod automatického řízení letu a jejich ověření s ohledem na současný stav poznání a budoucí využití bezpilotních letadlových systémů. Práce představuje proces návrhu automatického systému řízení letu s důrazem na přístupy z oblasti návrhu založeného na modelování (Model-Based Design). Nedílnou součástí tohoto procesu je tvorba matematického modelu letounu, který byl využit k syntéze zákonů řízení a k vytvoření simulačního rámce pro evaluaci stability a kvality regulace automatického systému řízení letu. Jádro této práce se věnuje syntéze zákonů řízení založených na unikátní kombinaci teorie optimálního a adaptivního řízení. Zkoumané zákony řízení byly integrovány do digitálního systému řízení letu, jenž umožňuje vysoce přesné automatické létání. Závěrečná část práce se zabývá ověřením a analýzou navrženého systému řízení letu a je rozdělena do 3 fází. První fáze ověření obsahuje evaluaci robustnosti a analyzuje stabilitu a robustnost navrženého systému řízení letu ve frekvenční oblasti. Druhá fáze, evaluace kvality regulace, probíhala v rámci počítačových simulací s využitím vytvořených matematických modelů v časové oblasti. V poslední fázi ověření došlo k integraci navrženého systému řízení letu do experimentálního letounu, sloužícího jako testovací platforma pro budoucí bezpilotní letadlové systémy a jeho evaluaci v rámci série letových experimentů.
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Plée, Vincent. "Prédiction du comportement de phases et des enthalpies de mélange de gaz naturels atypiques contenant de l'argon, du monoxyde de carbone et de l'hélium." Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0186/document.
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Le développement du modèle prédictif E-PPR78, basé sur une méthode de contribution de groupe, a été entrepris depuis plus de dix ans pour prédire le comportement de systèmes multiconstituants. Ce modèle repose sur l'équation d'état de Peng-Robinson dans sa version de 1978 et les règles de mélanges de Van der Waals. Il utilise un seul paramètre d'interaction binaire, kij, qui dépend de la température. Afin de permettre au modèle E-PPR78 de prédire le comportement du gaz naturel, trois nouveaux groupes sont ajoutés : le monoxyde de carbone, l'hélium et l'argon. Pour cela, il a été nécessaire de former une base de données expérimentales la plus large possible contenant les mesures d'équilibres de phase et d'enthalpies de mélange pour les systèmes binaires constitués par ces trois groupes ainsi que ceux définis dans les études précédentes et présents dans le gaz naturel. Après une description de la classification des diagrammes de phase de Van Konynenburg et Scott, le modèle E-PPR78 est présenté. La troisième partie est consacrée à l'ajout des trois nouveaux groupes au sein du modèle. Les résultats sont obtenus avec une précision satisfaisante. Il apparaît clairement que le modèle E PPR78 est capable de prédire le comportement du gaz naturel dans des conditions de températures et de pressions particulièrement largesThe development of the predictive E-PPR78 model, based on a contribution group method, has been undertaken since ten years to predict accurately the behaviour of multi-component systems. This model lies on the Peng-Robinson equation of state with classical Van der Waals mixing rules. It uses a unique binary interaction parameter, kij, which is temperature dependant. To enable the E-PPR78 model to predict the behavior of natural gases, three new groups are added: carbon monoxide, helium and argon. It was necessary to build an experimental database, as exhaustive as possible, containing phase equilibrium and enthalpies of mixing data for binary systems formed by these groups and those defined in previous studies and present in natural gases. After a description of the classification scheme of Van Konynenburg and Scott, the E-PPR78 model is described. The third part is about the addition of the three new groups to the model. It clearly appears that the E-PPR78 model is able to predict the fluid-phase behavior of natural gases over wide ranges of temperatures and pressures
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Nguyen, Vinh Q. "A Numerical Study of Burgers' Equation With Robin Boundary Conditions." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/31285.
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This thesis examines the numerical solution to Burgers' equation on a finite spatial domain with various boundary conditions. We first conduct experiments to confirm the numerical solutions observed by other researchers for Neumann boundary conditions. Then we consider the case where the non-homogeneous Robin boundary conditions approach non-homogeneous Neumann conditions. Finally we numerically approximate the steady state solutions to Burgers' equation with both the homogeneous and non-homogeneous Robin boundary conditions.Master of Science
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Lee, Kwang Won. "Equation of State of Superdense Matter and Neutron Star Properties." Diss., lmu, 2000. http://nbn-resolving.de/urn:nbn:de:bvb:19-3411.
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Carriere, Josef. "Neutron stars and the equation of state of dense matter." [Bloomington, Ind.] : Indiana University, 2005. http://wwwlib.umi.com/dissertations/fullcit/3183485.
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Thesis (Ph.D.)--Indiana University, Dept. of Physics, 2005.Source: Dissertation Abstracts International, Volume: 66-08, Section: B, page: 4269. Adviser: Charles J. Horowitz. Title from dissertation home page (viewed Oct. 10, 2006).
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James, B. E. "Studies on the equation of state of liquids and mixtures." Thesis, Swansea University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.637402.
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Du, Rand Marlie. "Practical equation of state for non-spherical and asymmetric systems." Thesis, Stellenbosch : University of Stellenbosch, 2004. http://hdl.handle.net/10019.1/16043.
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Thesis (PhD)--University of Stellenbosch, 2004.ENGLISH ABSTRACT: In this study an equation of state has been developed for the specific purpose of representing systems of simple non-polar spherical and chain-like components and their mixtures for practical applications. To be applied in engineering calculations, the model has to be accurate, be able to represent mixtures with large size asymmetry without the use large binary interaction parameters, and be mathematically simple enough to ensure rapid computations. The model is developed through a sequential evaluation of the statistical mechanical theory of particles and the various approaches available to extend it to real fluid systems. The equation of state developed in this work models the real fluid systems as interacting with a highly simplified two step potential model. The repulsive interactions are represented by a newly developed simplified form of the hard sphere equation of state, capable of representing the known hard sphere virial coefficients and phase behaviour to a high degree of accuracy. This equation has a realistic closest packed limiting density in between the idealised hard sphere fluid random and crystal structure limits. The attractive interactions between the particles are incorporated into the model through a perturbation expansion represented in the form of a double summation perturbation approximation. The perturbation matrix was optimised to have the lowest order in density necessary to still be able to accurately represent real fluid properties. In a novel approach to obtain simple mixing rules that result in the theoretically correct second virial coefficient composition dependence, the perturbation matrix is constrained in such a manner that only the first perturbation term has a term that is first order in density. From a detailed evaluation of the various methods available to represent chain-like non-spherical systems it was finally concluded that the Perturbed Hard Chain Theory provided an ideal compromise between model simplicity and accuracy, and this method is used to extend the equation to chain-like systems. Finally the model is extended to fluid mixtures by uniquely developed mixing rules resulting in the correct mixture composition dependence both at low and high system densities. The newly developed equation of state is shown to be capable of representing the pure component systems to a comparable degree of accuracy as the generally applied equations of state for non-spherical systems found in the literature. The proposed equation is furthermore also shown equal or improve on the predictive ability of these models in the representation offluid mixtures consisting out of similar chainlike or size and energetic asymmetric components. Finally, the computational time required to model the behaviour of large multi-component fluid mixtures using the new equation of state is significantly shorter that that of the other semi-empirical equations of state currently available in the literature.
AFRIKAANSE OPSOMMING: Hierdie werkstuk behels die ontwikkeling van ‘n toestandsvergelyking wat spesifiek gerig is op toepassings in alledaagse, praktiese ingenieurstipe berekeninge en daartoe instaat is om sisteme bestaande uit nie-polêre spferiese- en ketting-tipe komponente en hulle mengsels teKettingteorie (PHCT) die mees geskikde metode is vir hierdie doel en is op die vergelyking toegepas. As ‘n laaste stap in die toestandsvergelykingontwikkelling is daar mengreëls ontwikkel vir die vergelyking wat die korrekte samestellingsafhanklikheid toon vir beide die lae en hoë digtheidskondisies. Die model wat in hierdie studie ontwikkel is, is met verskeie ander bekende toestandsvergelykings, wat daartoe instaat is om nie-spferiese sisteme te modelleer, vergelyk en daar is gevind dat die nuwe model daartoe instaat is om suiwer sisteme net so goed as die bestaande vergelykings te modelleer. Verder is daar ook gevind dat die nuwe vergelyking die modellering van verskeie mensels van kettingtipe komponente en komponente van uiteenlopende groottes of interaksie energieë kan ewenaar of verbeter. Laastens is daar ook gevind dat die tyd nodig vir die modellering van die termodinamiese gedrag van mengsels van ‘n groot hoeveelheid komponente aansienlik korter is vir die nuwe model as die ander bekende semi-empiriese vergelykings. kan beskyf. Om aan hierdie vereistes te voldoen moet die toestandsvergelyking die relevante sisteme akkuraat kan modelleer, slegs klein interaksie parameters benodig om mengsels van komponente met groot verskille in molekulêre groottes akkuraat voor te stel en steeds wiskundig eenvoudig genoeg wees om vinnige berekeninge te verseker. Die vergelyking is ontwikkel deur ‘n sistematiese evaluering van die statisitiese meganiese teorie van partikels en die verskillende metodes om hierdie teorië op werklike sisteme toe te pas. Die toestandsvergelyking beskryf die intermolekulêre interaksie tussen die verskillende komponente met ‘n hoogs vereenvoudigde twee-stap interaksie potensiaal model. Die afstotende kragte tussen die komponente word in ag geneem deur ‘n nuwe vergelyking wat ontwikkel is om die gedrag van ‘n ideale harde spfeer sisteem te modelleer. Hierdie hardespfeermodel is daartoe instaat om die viriale koeffisiënte en die fase gedrag van teoretiese harde spfeer sisteme akkuraat te modelleer, en het ‘n maksimum digtheidslimiet wat tussen teoretiese waardes van ‘n perfek geordende en nie-geordende harde spheer sisteem lê. Die aantrekkinskragte tussen die partikels word beskou as ‘n perturbasie van die harde-spheer vergelyking. ‘n Term bestaande uit ‘n dubbelle sommasiefunksie word gebruik om hierdie perturbasie uitbreiding voor te stel. Die sommasie term is geoptimiseer sodat die finale toestandsvergelyking die laagste digtheidsgraad het wat steeds tot ‘n akkurate voorstelling van die termodinamiese gedrag van werklike sisteme lei. Die sommasiefunksie is so gespesifiseer dat die eerste term van die perturbasie uitbreiding slegs ‘n eerste graadse orde in digtheid het in ‘n unieke benadering om te verseker dat die mengreëls van die toestandsvergelyking die teoreties korrekte samestellingafhanklikheid van die mengselvirialekoeffisiente tot gevolg het. ‘n Deeglike ondersoek van die verskillende metodes om die toepassing van die toestandsvergelyking uit te brei tot die moddellering van nie-spheriese ketting-tipe molekules is gedoen en daar is uiteindelik tot die gevolgtrekking gekom dat die Geperturbeerde Harde
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Wu, Zhibo. "Equation of state for polytetrafluoroethylene (PTFE) and mixtures with PTFE." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29696.
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Thesis (Ph.D)--Aerospace Engineering, Georgia Institute of Technology, 2009.Committee Chair: Hanagud,Sathya; Committee Member: Apetre, Nicoleta; Committee Member: Kardomateas, George; Committee Member: McDowell, David L.; Committee Member: Ruzzene, Massimo. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Wells, David Reese. "A Two-Level Method For The Steady-State Quasigeostrophic Equation." Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/23090.
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The quasi-geostrophic equations (QGE) are a model of large-scale ocean flows. We consider a pure stream function formulation and cite results for optimal error estimates for finding approximate solutions with the finite element method. We examine both the time dependent and steady-state versions of the equations. Numerical experiments verify the error estimates.We examine the Argyris finite element and derive the transformation matrix necessary to perform calculations on the reference triangle. We use the Argyris element because it is a high-order, conforming finite element for fourth order problems.
In order to increase computational efficiency, we consider a two-level method to linearize the system of equations. This allows us to solve a small, nonlinear system and then use the result to linearize a larger system.
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Falk, Katerina. "Measurement of equation of state of compressed hydrogen and deuterium." Thesis, University of Oxford, 2011. https://ora.ox.ac.uk/objects/uuid:9aa33691-48f0-430f-a8cf-48795ad8f7c7.
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Detailed understanding of the equation of state of light elements such as the hydrogen isotopes in the warm dense matter (WDM) regime is essential for the modeling of the inner structure of many astrophysical objects, in particular Jovian planets as well as inertial confinement fusion (ICF) research. In these systems quantum degeneracy and strong inter-particle forces play an important role making its theoretical description extremely challenging. The Omega laser was used to drive a planar shock wave in cryogenically cooled deuterium creating WDM conditions. We used a set of independent diagnostics to measure the thermodynamic conditions of WDM including velocity interferometry (VISAR), streaked optical pyrometry (SOP) and x-ray Thomson scattering (XRTS). With a narrow-band x-ray backlighter probe at backscattering geometry the spectrally resolved XRTS accessed the boundary of collective and non-collective regimes making our measurement sensitive to both electron temperature and density. This work presents a full set of measurements of the thermodynamic properties for different laser intensity drives creating warm dense deuterium at various degrees of degeneracy and coupling. The measured electron densities and temperatures ranged between 0.2 and 2.15x1023 cmâ3 and 0.6 â 20 eV respectively. The scattering measurement confirmed the findings from the VISAR and SOP data and together densityfunctional molecular dynamics (DFT-MD) simulations provides a novel self-consistent approach for an accurate characterization of the microscopic structure of WDM. Complementary to the laser compression work, findings from project employing static compression hydrogen with the use of diamond anvil cells is also be presented. The first direct measurement of the local field correction to the Coulomb interactions in degenerate plasma was obtained from inelastic scattering (20 keV probe) at the Diamond Light Source synchrotron facility.
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Langenbach, Kai [Verfasser]. "Development of an Equation of State Incorporating Molecular Architecture / Kai Langenbach." Aachen : Shaker, 2013. http://d-nb.info/1050345800/34.
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McGauley, Patrick James. "Experimental and equation of state studies of model gas condensate mixtures." Thesis, Imperial College London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244516.
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Patel, Keyurkumar S. "Automatic generation of global phase equilibrium diagram from equation of state." [Tampa, Fla] : University of South Florida, 2007. http://purl.fcla.edu/usf/dc/et/SFE0002327.
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Draper, Christian D. "Impact of a Finite-Temperature Equation of State on Neutron Stars." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2603.
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In this research, we study how a finite-temperature nuclear equation of state suitable for astrophysical simulations impacts the oscillation modes of neutron stars. We chose the Shen equation of state (EOS) because it accurately describes both stable and unstable nuclei as well as nuclear incompressibilities. I modified the existing MHD code at BYU, the HAD code, to call a lookup table for the Shen EOS for use at run time, and added a Newton-Raphson method algorithm to convert conserved variables to primitive variables. The algorithm was tested and verified by evolving a stable neutron star for several dynamical times and evolving the same star at different resolutions. The normal mode frequency of the neutron star with the Shen EOS was measured and compared to those for neutron stars with an ideal gas EOS found by Font et. al. We found that the fundamental mode of the neutron star using the Shen EOS was slightly larger than that of the ideal gas EOS. This difference is due to the Shen EOS producing stars that are stiffer, increasing the sound speed.
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Wong, Henry H. L. "Correlation of viscosity of dense gases with an equation of state." Thesis, University of Ottawa (Canada), 1992. http://hdl.handle.net/10393/7911.
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This research was undertaken with the objective of calculating the viscosity of pure gases and their mixtures using the Enskog theory together with a volume translated Peng-Robinson (TPR) equation of state. The TPR equation was used to predict the density which is an independent variable of the radial distribution function ($\chi$) involved in the Enskog equation. In the original Enskog equation,$$\eta=\eta\sb0b\sb0\rho(1/b\sb0\rho\chi + 0.800 + 0.7614(b\sb0\rho\chi))$$the radial distribution function $\chi$ was added to the $\eta\sb0 b\sb0\rho$ term and the constant 0.8 was treated as substance and temperature dependent in this research. The modified Enskog equation$$\eta = \eta\sb0(b\sb0\rho\chi)({1.000\over (b\sb0\rho\chi)} + H\sb{(T)} + 0.7614(b\sb0\rho\chi))$$was found to be satisfactory for the representation of the viscosity for real gases. Extensive comparisons of calculated viscosities with experimental data for pure gases were undertaken over a temperature range from 200 to 1000 K and a pressure range from 1 to 980 atm. The overall average absolute deviations for the viscosity of gas mixtures such as carbon dioxide-methane, argon-neon, carbon dioxide-krypton and hydrogen-nitrogen were less than one percent. The procedure for the prediction of the viscosities for mixtures is simple and straightforward. Only the critical parameters, the accentric factor, and the viscosity at low pressure for the gases are required.
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Campbell, David Alexander. "Bayesian collocation tempering and generalized profiling for estimation of parameters from differential equation models." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=103368.
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The widespread use of ordinary differential equation (ODE) models has long been underrepresented in the statistical literature. The most common methods for estimating parameters from ODE models are nonlinear least squares and an MCMC based method. Both of these methods depend on a likelihood involving the numerical solution to the ODE. The challenge faced by these methods is parameter spaces that are difficult to navigate, exacerbated by the wide variety of behaviours that a single ODE model can produce with respect to small changes in parameter values.In this work, two competing methods, generalized profile estimation and Bayesian collocation tempering are described. Both of these methods use a basis expansion to approximate the ODE solution in the likelihood, where the shape of the basis expansion, or data smooth, is guided by the ODE model. This approximation to the ODE, smooths out the likelihood surface, reducing restrictions on parameter movement.
Generalized Profile Estimation maximizes the profile likelihood for the ODE parameters while profiling out the basis coefficients of the data smooth. The smoothing parameter determines the balance between fitting the data and the ODE model, and consequently is used to build a parameter cascade, reducing the dimension of the estimation problem. Generalized profile estimation is described with under a constraint to ensure the smooth follows known behaviour such as monotonicity or non-negativity.
Bayesian collocation tempering, uses a sequence posterior densities with smooth approximations to the ODE solution. The level of the approximation is determined by the value of the smoothing parameter, which also determines the level of smoothness in the likelihood surface. In an algorithm similar to parallel tempering, parallel MCMC chains are run to sample from the sequence of posterior densities, while allowing ODE parameters to swap between chains. This method is introduced and tested against a variety of alternative Bayesian models, in terms of posterior variance and rate of convergence.
The performance of generalized profile estimation and Bayesian collocation tempering are tested and compared using simulated data sets from the FitzHugh-Nagumo ODE system and real data from nylon production dynamics.
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HAMDY, MOHAMED ADEL. "DETERMINATION OF THE SOLAR CELL EQUATION PARAMETERS: NEW METHODS, EXISTING METHODS, ANALYSIS AND COMPARISON." Diss., The University of Arizona, 1985. http://hdl.handle.net/10150/188119.
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Presented here is an analysis of some of the existing methods used for the determination of the series resistance of solar cells which is one of the key parameters in solar cell fabrication and technology together with the diode ideality factor and the reverse saturation current. These methods are based on the network analysis of the single-exponential lumped constant parameters model which has been accepted as being operationally sufficient to describe the current-voltage characteristics of the solar cell. The methods analyzed in this study are divided into two main groups. Methods using two I-V characteristics and methods using a single I-V output curve. For comparison purposes, all methods are applied first using data extracted from existing I-V curves and then using in-lab measurements of a commercial solar cell. It is demonstrated that the determination of the series resistance of solar cells using two I-V characteristics has several advantages over methods using a single I-V output curve. It becomes evident that methods which use a single I-V output curve are only accurate for cells operating under very high illumination conditions. At normal intensities, however, such methods result in erroneous R(s) values. This is due to the assumption of a constant diode ideality factor along the entire I-V output curve used in the derivation of these methods. It is shown that this assumption is inaccurate at normal intensity levels and can be appropriate only under very high illuminations. Three new methods are proposed in this study. One of the methods presents a new approach in determining the solar cell equation parameters. The new approach relies upon treating the diode ideality factor of the solar cell as a variable that is a function of both the terminal current and the light intensity level. The method uses two I-V output curves at different illumination levels in determining all solar cell parameters: The series resistance, the diode ideality factor and the reverse saturation current. Although somehow tedious, the new approach shows that, for accurate modeling of solar cells and prediction of illuminated characteristics at different light levels based on the single-exponential model, the diode ideality factor should be treated as a variable while the series resistance is held constant. Comparison between all methods is presented and a reasonable judgement and recommendations concerning the best method to be used are given.
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Cowey, Lisa. "Characterisation techniques and critical parameters for anisotropic superconductors." Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314865.
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Costas, Basin Miguel Antonio. "Equation of state and structure in non-electrolyte liquids and their mixtures." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=71982.
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Structural effects in hydrogen and non-hydrogen bonded liquids and their mixtures have been studied using several experimental techniques and theoretical approaches. Apparent heat capacities and volumes of linear alcohols in hydrocarbons were determined at very low alcohol concentrations and their self-association in solution discussed in terms of the Treszczanowicz-Kehiaian theory. An extension of this theory was used to describe cholesterol self-association and its interactions with tripalmitin and lecithin. Heat capacities of water-organic mixtures are reported. It is found that water behaves as a lower alcohol at the organic-rich concentration range. At the water-rich end, Shinoda's views on water structuring around hydrophobes are supported. Thermal pressure coefficients of cyclohexane + normal and branched alkanes are consistent with the presence of orientational order in the long pure n-alkanes. Excess volumes for mixtures of alkanes with liquids of different internal pressures are predicted using Flory theory. The anomalous thermodynamic behaviour of cyclopentane mixed with cyclic and branched alkanes has been studied through the measurement of cyclopentane spin-lattice relaxation times in these mixtures. An extension of Sanchez-Lacombe theory for pure liquids is described and the molecular parameters obtained for sixty common substances. An equation of state for pure n-alkanes with correlations of molecular orientations is presented.
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Chilakapati, Goutami. "An equation of state for systems containing aqueous solutions of strong electrolytes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ38621.pdf.
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Patel, Birjukumar. "Phase behaviour of aqueous electrolyte solutions from an equation of state approach." Thesis, Imperial College London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.415343.
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Lee, Isobel Micheline. "The existance of multiple steady-state solutions of a reaction-diffusion equation." Thesis, University of Oxford, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329934.
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Burger, Florian. "The finite temperature QCD phase transition and the thermodynamic equation of state." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2013. http://dx.doi.org/10.18452/16679.
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In dieser Arbeit wird mit Hilfe der Gitter-Methode der Phasenübergang/Crossover bei nicht verschwindender Temperatur der Quantenchromodynamik mit zwei Quark Flavour untersucht sowie die thermodynamische Zustandsgleichung berechnet. Es wird dabei die Wilson twisted-mass Formulierung der Quark-Wirkung verwendet, welche hinsichtlich des Kontinuum-Limes eine automatische Verbesserung birgt. Erste belastbare Resultate mit dieser Wirkung bei endlicher Temperatur werden in dieser Arbeit gezeigt. Mehrere kleine Werte der Pion-Masse werden betrachtet mit dem Ziel, Aufschluss über die Ordnung des Phasenüberganges im chiralen Limes zu erhalten. Im Bereich der von uns simulierten Pion-Massen zwischen 300 und 700 MeV wird hierbei lediglich ein Crossover-Übergang beobachtet. Die Abhängigkeit der gemessenen Crossover-Temperatur von der Masse wird für eine Extrapolation zu verschwindender Masse hin verwendet unter der Annahme verschiedener Szenarien für den chiralen Limes. Dazu komplementär wird das chirale Kondensat, der Ordnungsparameter der spontanen Brechung der chiralen Symmetrie, vor dem Hintergrund der so genannten magnetischen Zustandsgleichung untersucht, welche das universelle Verhalten in der Nähe des Phasenüberganges für die Universalitätsklasse des O(4) Modells angibt. Hinsichtlich der Thermodynamik wird ausgehend von der Spur-Anomalie und unter Benutzung der Temperatur-Integral Methode der Druck und die Energiedichte im Crossover-Gebiet berechnet. Der Kontinuum-Limes der Spur-Anomalie wird mit mehreren Gitterdiskretisierungen der Temperatur Nt sowie unter Zuhilfenahme einer tree-level Korrektur untersucht.In this thesis we report about an investigation of the finite temperature crossover/phase transition of quantum chromodynamics and the evaluation of the thermodynamic equation of state. To this end the lattice method and the Wilson twisted mass discretisation of the quark action are used. This formulation is known to have an automatic improvement of lattice artifacts and thus an improved continuum limit behaviour. This work presents first robust results using this action for the non-vanishing temperature case. We investigate the chiral limit of the two flavour phase transition with several small values of the pion mass in order to address the open question of the order of the transition in the limit of vanishing quark mass. For the currently simulated pion masses in the range of 300 to 700 MeV we present evidence that the finite temperature transition is a crossover transition rather than a genuine phase transition. The chiral limit is investigated by comparing the scaling of the observed crossover temperature with the mass including several possible scenarios. Complementary to this approach the chiral condensate as the order parameter for the spontaneous breaking of chiral symmetry is analysed in comparison with the O(4) universal scaling function which characterises a second order transition. With respect to thermodynamics the equation of state is obtained from the trace anomaly employing the temperature integral method which provides the pressure and energy density in the crossover region. The continuum limit of the trace anomaly is studied by considering several values of Nt and the tree-level correction technique.
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Ebrahimpour, Misagh. "Dynamic and steady state modeling of VRD column in equation-oriented environment." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/3/3137/tde-18072016-083635/.
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Dynamic and steady state modeling and simulation validation of an industrial depropanizer owned by Petrobras are carried out in the Equation-Oriented environment using EMSO (Environment for Modeling, Simulation and Optimization). The depropanizer is a high purity distillation column with high nonlinear behavior because of the strong interactions due to the vapor recompression. Furthermore, the difference between internal and external material/energy flows causes a complex multitime-scale dynamics. Modeling such process is a challenging problem due to these characteristics. Initially, a steady state model, robust, fast and precise, able to provide steady state predictions that are necessary for effective implementation of Real Time Optimization (RTO) was developed in EMSO. In addition, the modeling of dynamic equilibrium processes often results in higher index DAE systems. Usually, phenomenological relationships are used to solve the index problem, but this approach gives rise to errors as a result of unknown parameters and project details that are assumed. Considering that the column\'s response to composition changes, in general, takes place over a timescale one or two order of magnitude slower than those of flow rate changes, an approach similar to a proportional loop with arbitrarily large gain is used as an alternative to solve the index problem. The dynamic model structure is based on the steady state model and contains more than nine thousand equations. Validation simulation results from comparison between real plant data and dynamic model have shown that the proposed approach is able to predict the dynamic behavior of the column properly.O propósito desta dissertação é realizar a modelagem, simulação e validação de um modelo, tanto em estado estacionário quanto dinâmico, de uma unidade despropanizadora da Petrobras. Para o estudo foi utilizado o ambiente orientado a equações, EMSO (Environment for Modeling, Simulation and Optimization). A coluna despropanizadora é uma torre de destilação de alta pureza que possui um comportamento altamente não-linear devido às fortes interações causadas pelo sistema de recompressão do vapor. A modelagem desse processo é um desafio devido às características que apresenta. Inicialmente, foi desenvolvido nesse ambiente um modelo em estado estacionário, robusto, rápido e preciso, com a finalidade de prover as predições em estado estacionário necessárias para a implementação efetiva de uma rotina de otimização em tempo real, Real Time Optimization (RTO). A modelagem dinâmica de processos em equilíbrio resulta, frequentemente, em sistemas de equações algébrico diferenciais de índice superior. Para solução do problema de índice normalmente são utilizadas relações fenomenológicas, as quais introduzem novas fontes de erros provenientes de parâmetros e detalhes de projeto desconhecidos. Considerando que a resposta da coluna em relação às mudanças na composição, em geral, ocorre em uma escala de tempo de ordem de grandeza duas vezes mais lenta que as respostas às mudanças nas vazões, foi proposta uma abordagem similar a um controlador proporcional com ganho elevado para substituir as relações fenomenológicas e assim resolver o problema de índice. A estrutura do modelo dinâmico é baseada na do modelo estacionário e contém mais de nove mil equações. A validação dos resultados da simulação com dados reais da planta mostra que a abordagem proposta consegue prever satisfatoriamente o comportamento do sistema.