Dissertationen zum Thema „Thermodynamic Equilibrium Calculations“
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Qu, Jingang. „Acceleration of Numerical Simulations with Deep Learning : Application to Thermodynamic Equilibrium Calculations“. Electronic Thesis or Diss., Sorbonne université, 2023. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2023SORUS530.pdf.
Der volle Inhalt der QuelleNumerical simulations are a powerful tool for analyzing dynamic systems, but can be computationally expensive and time-consuming for complex systems with high resolution. Over the past decades, researchers have been striving to accelerate numerical simulations through algorithmic improvements and high-performance computing (HPC). More recently, artificial intelligence (AI) for science is on the rise and involves using AI techniques, specifically machine learning and deep learning, to solve scientific problems and accelerate numerical simulations, having the potential to revolutionize a wide range of fields. The primary goal of this thesis is to speed up thermodynamic equilibrium calculations by means of techniques used to accelerate numerical simulations. Thermodynamic equilibrium calculations are able to identify the phases of mixtures and their compositions at equilibrium and play a pivotal role in many fields, such as chemical engineering and petroleum industry. We achieve this goal from two aspects. One the one hand, we use deep learning frameworks to rewrite and vectorize algorithms involved in thermodynamic equilibrium calculations, facilitating the use of diverse hardware for HPC. On the other hand, we use neural networks to replace time-consuming and repetitive subroutines of thermodynamic equilibrium calculations, which is a widely adopted technique of AI for science. Another focus of this thesis is to address the challenge of domain generalization (DG) in image classification. DG involves training models on known domains that can effectively generalize to unseen domains, which is crucial for deploying models in safety-critical real-world applications. DG is an active area of research in deep learning. Although various DG methods have been proposed, they typically require domain labels and lack interpretability. Therefore, we aim to develop a novel DG algorithm that does not require domain labels and is more interpretable
Zinser, Alexander [Verfasser], Kai [Gutachter] Sundmacher und Achim [Gutachter] Kienle. „Dynamic methods for thermodynamic equilibrium calculations in process simulation and process optimization / Alexander Zinser ; Gutachter: Kai Sundmacher, Achim Kienle“. Magdeburg : Universitätsbibliothek Otto-von-Guericke-Universität, 2019. http://d-nb.info/1219937207/34.
Der volle Inhalt der QuelleHöglund, Andreas. „Electronic Structure Calculations of Point Defects in Semiconductors“. Doctoral thesis, Uppsala universitet, Fysiska institutionen, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-7926.
Der volle Inhalt der QuelleBelsito, Danielle L. „Application of Computational Thermodynamic and Solidification Kinetics to Cold Sprayable Powder Alloy Design“. Digital WPI, 2014. https://digitalcommons.wpi.edu/etd-dissertations/28.
Der volle Inhalt der QuelleLundholm, Karin. „Fate of Cu, Cr, As and some other trace elements during combustion of recovered waste fuels“. Doctoral thesis, Umeå : Department of Applied Physics and Electronics, Umeå Univ, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1132.
Der volle Inhalt der QuelleBratberg, Johan. „Phase equilibria and thermodynamic properties of high-alloy tool steels : theoretical and experimental approach“. Doctoral thesis, Stockholm, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-453.
Der volle Inhalt der QuelleYamada, Ryo. „Application of Steepest-Entropy-Ascent Quantum Thermodynamics to Solid-State Phenomena“. Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/85866.
Der volle Inhalt der QuellePh. D.
Many engineering materials have physical and chemical properties that change with time. The tendency of materials to change is quantified by the field of thermodynamics. The first and second laws of thermodynamics establish conditions under which a material has no tendency to change; these conditions are called equilibrium states. When a material is not in an equilibrium state, it is able to change spontaneously. Classical thermodynamics reliably identifies whether a material is susceptible to change, but it is incapable of predicting how change will take place or how fast it will occur. These are kinetic questions that fall outside the purview of thermodynamics. A relatively new theoretical treatment developed by Hatsopoulos, Gyftopoulos, Beretta and others over the past forty years extends classical thermodynamics into the kinetic realm. This framework, called steepest-entropy-ascent quantum thermodynamics (SEAQT), combines the tools of thermodynamics with quantum mechanics through a postulated equation of motion. Solving the equation of motion provides a kinetic description of the path a material will take as it changes from a non-equilibrium state to stable equilibrium. To date, the SEAQT framework has been applied primarily to systems of gases. In this dissertation, solid-state models are employed to extend the SEAQT approach to solid materials. The SEAQT framework is used to predict the thermal expansion of silver, the magnetization of iron, and the kinetics of atomic clustering and ordering in binary solid-solutions as a function of time or temperature. The model makes it possible to predict a unique kinetic path from any arbitrary, non-equilibrium, initial state to a stable equilibrium state. In each application, the approach is tested against experimental data. In addition to reproducing the qualitative kinetic trends in the cases considered, the SEAQT framework shows promise for modeling the behavior of materials far from equilibrium.
Davie, Stuart James. „Relative Free Energies from Non-Equilibrium Simulations: Application to Changes in Density“. Thesis, Griffith University, 2014. http://hdl.handle.net/10072/365922.
Der volle Inhalt der QuelleThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Biomolecular and Physical Sciences
Science, Environment, Engineering and Technology
Full Text
Razavi, Seyed Mostafa. „OPTIMIZATION OF A TRANSFERABLE SHIFTED FORCE FIELD FOR INTERFACES AND INHOMOGENEOUS FLUIDS USING THERMODYNAMIC INTEGRATION“. University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1481881698375321.
Der volle Inhalt der QuelleMaghsoodloobabakhani, Saheb. „Cristallisation à l'équilibre et hors équilibre d'hydrates mixtes de gaz : Mesures PVTx et modélisation thermodynamique“. Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEM027.
Der volle Inhalt der QuelleIn this work, in order to investigate the non-equilibrium behaviors of mixed clathrate hydrates, vapor-liquid-hydrate phase equilibria of mixed gas hydrates from CH4-C2H6-C3H8-nC4H10-CO2-N2 are studied. Two different experimental procedures are used: at quick and slow crystallization rates. The aim is to examine the effects of crystallization rate on the final state, either under usual dynamic (quick formation) or steady state conditions (slow formation). Unlike most of the literature data, providing temperature-pressure-vapor composition (PTy) results, this study also furnishes hydrate composition, volume, storage capacity, density, or hydration number and water conversion. At quick crystallization, hydrate volume increases from 2% to 69% according to the gas mixture. Moreover, storage capacity decreases with increasing rate of crystallization. In addition, a thermodynamic model, based on classical van der Waals and Platteuw method and Kihara potential, has been used. A new set of Kihara parameters for propane, based on slow crystallization, has been obtained successfully and compared to the literature.Besides, a review on guest composition in hydrates from experimental results is suggested, based on open literature. Then, the capability of thermodynamic modeling to simulate these rare data has been investigated. While simulation tools are interesting to predict phase equilibria for light molecules, they become less reliable when phase transition occurs in the system, or when heavier molecules are involved. In addition, the use of RAMAN spectroscopy has illustrated phase transition for CO2/C3H8 mixed hydrates under CO2 rich gas conditions.To conclude, the rate of crystallization significantly influences the process of mixed hydrates formation. The use of a thermodynamic flash shows that slow crystallization is necessary to satisfy the thermodynamic equilibrium, and thus increase storage capacity, and optimize hydrate processes
Ammar, Mohamed Naceur. „Modélisation d'opérations unitaires et méthodes numériques de calcul d'équilibre liquide-vapeur“. ENMP, 1986. http://www.theses.fr/1986ENMP0002.
Der volle Inhalt der QuelleLe, Quang-Du. „Investigation de la cristallisation hors-équilibre des clathrates hydrates de gaz mixtes : une étude expérimentale comparée à la modélisation thermodynamique avec et sans calculs flash“. Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEM002/document.
Der volle Inhalt der QuelleThe scientific goal of this thesis is based on the acquisition of experimental data and the modeling of the composition of clathrates gas hydrate. The domains of application concern the gas separation and storage, water purification, and energy storage using change phase materials (PCMs).Our research team has recently demonstrated that the composition of gas hydrates was sensitive to the crystallization conditions, and that the phenomenon of formation was out of thermodynamic equilibrium. During this thesis, we have investigated several types of crystallization, which are based on the same initial states. The goal is to point out the differences between the initial solution composition and the final solution composition, and to establish a link between the final state and the crystallization rate.Depending on the rate of crystallization (slow or fast), the acquisition time of experimental data lasted from a few days to several weeks. The experimental tests were performed inside a stirred batch reactor (autoclave, 2.44 or 2.36 L) cooled with a double jacket. Real-time measurements of the composition of the gas and the liquid phases have been performed, in order to calculate the composition of the hydrate phase using mass balance calculations. Depending on the crystallization mode, we have identified several variations of the composition of the hydrate phase and final hydrate volume.We have established a successful thermodynamic model, which indicates the composition of the hydrate phase and hydrate volume in thermodynamic equilibrium state using a gas mixture which had never been used before in the literature. So this thermodynamic model has required an extremely slow experimental test. These tests were also long in order to be sure of the thermodynamic equilibrium state.We are currently establishing a kinetics model in order to model the deviations from the reference point of equilibrium of our experimental tests which were carried out at a high crystallization rate
Feja, Steffen. „Darstellung und Charakterisierung ternärer Molybdate in den Systemen M - Mo - O (M = Sn, Pb, Sb)“. Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2004. http://nbn-resolving.de/urn:nbn:de:swb:14-1101201293828-88525.
Der volle Inhalt der QuelleMartin, Petitfrere. „EOS based simulations of thermal and compositional flows in porous media“. Thesis, Pau, 2014. http://www.theses.fr/2014PAUU3036/document.
Der volle Inhalt der QuelleThree to four phase equilibrium calculations are in the heart of tertiary recovery simulations. In gas/steam injection processes, additional phases emerging from the oil-gas system are added to the set and have a significant impact on the oil recovery. The most important computational effort in many chemical process simulators and in petroleum compositional reservoir simulations is required by phase equilibrium and thermodynamic property calculations. In field scale reservoir simulations, a huge number of phase equilibrium calculations is required. For all these reasons, the algorithms must be robust and time-saving. In the literature, few simulators based on equations of state (EoS) are applicable to thermal recovery processes such as steam injection. To the best of our knowledge, no fully compositional thermal simulation of the steam injection process has been proposed with extra-heavy oils; these simulations are essential and will offer improved tools for predictive studies of the heavy oil fields. Thus, in this thesis different algorithms of improved efficiency and robustness for multiphase equilibrium calculations are proposed, able to handle conditions encountered during the simulation of steam injection for heavy oil mixtures. Most of the phase equilibrium calculations are based on the Newton method and use conventional independent variables. These algorithms are first investigated and different improvements are proposed. Michelsen’s (Fluid Phase Equil. 9 (1982) 21-40) method for multiphase-split problems is modified to take full advantage of symmetry (in the construction of the Jacobian matrix and the resolution of the linear system). The reduction methods enable to reduce the space of study from nc (number of components) for conventional variables to M (M<
Saber, Nima. „Phase behaviour prediction for ill-defined hydrocarbon mixtures“. Phd thesis, 2011. http://hdl.handle.net/10048/1757.
Der volle Inhalt der QuelleChemical Engineering
Bastos, Luís Diogo dos Santos. „Metal oxide nanoparticle formation through detonation - modeling evaluation“. Master's thesis, 2015. http://hdl.handle.net/10316/38997.
Der volle Inhalt der QuelleThe production of ceramics nanoparticles by detonation of metalized emulsions is an important alternative to the traditional metallurgic methods. The small size of the obtained particles (high pressure reaction), the reliability of reaction process (detonation), high temperature post-detonation particles formation with extremely fast cooling (due to the speed of adiabatic expansion of the gases), and the control of product condensed phase composition are the main advantages. This innovative emulsion detonation synthesis method (EDSM), can be included in either solid or gas-phase synthesis manufacturing process depending on the chosen conditions, and emerges as the most promising technique for the industrialization of the nanoparticles production. In this work, this production method is studied for metal oxide formation. These materials are chosen given its excellent properties, due to the combination of covalent and ionic links with strong chemical bonds, such as: high hardness and mechanical resistance at high temperature, high melting temperatures which allows good thermal and electric insulating applications and the exhibition of high chemical stability in hostile environment. These properties make these ceramic materials appropriate for several industrial applications. Metal oxide production from detonation can be predicted using Thermochemical Codes, in this case with THOR Code. For the modelling of this particles formation, the temperature of detonation is the most important parameter to know, as well as the products concentration, being these variables the focus of the modeling problem. Given this problem, the implementation of a thermal equation of state and energetic equation of state is essential in order to better define solid products. Therefore, it’s necessary to derive this equations for each phase of solid condensed species. In this work a Cowan & Fickett Thermal Equations of State and a Mie-Grüneisen approach with thermal contribution given by Debye model Energetic Equation of State are used to describe these solids. These equations are different and characterize more accurately the behavior of metal oxide particles (solid condensed phase) formation in Thor than the ones previously used (which represented metal oxide particles as a high density gas (Gordon McBride Polynomials)). The parameters used in this models are known only for common and wellstudied products, so the objective of this work was finding these parameters for Alumina, Zirconia, Titania and Magnesia, and simulate each one of this material formation. Before the metal oxide condensed specie formation analysis, a benchmark was made with Carbon condensed species formation, given its common and abundant presence in reactive mixtures formed in shock compressed energetic materials. The results comparison proved the validity of the models and methods used in the derivation of the parameters and the possibility of extrapolate them for other simulations. Multiple papers were studied and reviewed in order to derive this parameters for each material at a given phase. These equations were applied in Thor Database, which allowed the simulation of their formation and comparison with the previous method, proving the better accuracy in obtaining the Temperature and Pressure of Detonation, as well as the product concentration.
A produção de nanopartículas cerâmicas por detonação de emulsões metalizadas é uma alternativa importante aos métodos metalúrgicos tradicionais. O tamanho reduzido das partículas obtidas (reação a alta pressão), a fiabilidade do processo da reação (detonação), a formação de partículas em altas temperaturas na pós-detonação com arrefecimento rápido (devido à elevada velocidade de expansão adiabática dos gases) e o controlo da composição da fase condensada são as principais vantagens deste método. Este processo de fabricação inovador, Emulsion Detonation Synthesis Method (EDSM), pode ser definido como um processo de síntese em fase sólida ou gasosa, de acordo com as condições escolhidas, e destaca-se como uma técnica promissora na industrialização da produção de nanopartículas. Neste trabalho é analisada a produção de nanopartículas de Óxidos Metálicos por detonação. Estes materiais são escolhidos devido às suas excelentes propriedades, devido à coexistência de ligações iónicas e covalentes com fortes ligações, tais como: elevada dureza e resistência mecânica a temperaturas elevadas, altas temperaturas de fusão que permitem a sua introdução em aplicações de isolamento térmico e elétrico e ainda a elevada estabilidade química em ambiente adverso. Estas propriedades fazem destes materiais cerâmicos apropriados para diversas aplicações industriais. A produção de óxidos metálicos por detonação pode ser modelada através de programas termoquímicos, neste caso através do programa termoquímico THOR. Para a modelação da formação destas partículas, a temperatura de detonação é a variável mais importante de obter, tal como a concentração dos produtos, sendo considerados o principal objetivo de modelação. Por esta razão, a implementação de equações de estado (térmicas e energéticas) é essêncial, de modo a melhor definir os produtos sólidos. Assim, é necessário derivar estas equações para cada fase de material condensado nos produtos da detonação. Neste trabalho, são utilizadas as Equações Cowan & Fickett para a definição do estado térmico e uma abordagem Mie-Grüneisen com a contribuição térmica dada pelo modelo de Debye para a equação de estado energética, de modo a descrever os sólidos definidos. Estas equações caracterizam mais fielmente o comportamento da formação de partículas de óxidos metálicos (fase sólida condensada) no THOR do que as equações usadas previamente (que representavam as partículas como um gás de elevada densidade (Gordon McBride Polynomials)). Os parâmetros usados nestes modelos são conhecidos apenas para produtos extensamente estudados. Por este motivo, este trabalho centra-se na determinação destes parâmetros para a Alumina, Zircónica, Titania e Magnésia, simulando posteriormente a formação de cada um destes materiais através das equações definidas. Antes da análise da formação de óxidos metálicos na detonação foi realizado um estudo de referência através da formação de espécies condensadas de Carbono, dado o seu extenso estudo e a sua presença nos produtos de misturas reativas de materiais energéticos. A comparação destes resultados provou a validade dos modelos e métodos utilizados na derivação dos parâmetros, bem como a possibilidade de extrapolação para outras simulações. Foram analisados vários artigos com o objetivo de derivar os parâmetros referidos para cada material numa dada fase. Estas equações foram implementadas na base de dados do THOR, o que permitiu a simulação da sua formação e a comparação com os métodos anteriormente usados, provando uma melhor precisão na obtenção das temperaturas e pressões de detonação, bem como na previsão de concentração dos produtos.