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Development, validation, and application of a solver for non-isothermal non-adiabatic packed bed reactors
Hlavatý, Tomáš ; Isoz, Martin ; Khýr, M.
Packed bed reactors are the most frequently used devices to perform heterogeneously catalyzed reactions on industrial scales. The main contribution of our work is the development of a numerical model applicable to simulations of such reactors. The developed model is based on the finite volume method, couples the momentum, mass and energy balances, and is free of any empirical closures. As such, the solver falls into the domain of the direct numerical simulation. In the talk, we will (i) present the new solver fundamental working principles, (ii) report on the verication of each of the solver components against existing literature data and (iii) demonstrate an application of the solver on an industrially relevant case of ethylene oxichlorination performed in a tubular reactor packed with Raschig rings coated by CuCl2 catalyst.
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Simulation of heterogeneously-catalyzed non-isothermal reactive flow in industrial packed beds
Hlavatý, Tomáš ; Isoz, Martin ; Khýr, M.
Packed bed reactors are the most frequently used devices to perform heterogeneously catalyzed reactions on industrial scales. An industrial real-life heterogeneous catalysis is complex process that combines fully three-dimensional mass, momentum and energy transport on several scales. In the present work, we leverage our previously developed CFD solver for non-isothermal heterogeneously catalyzed reactive flow based on the finite volume method and couple it with our\nin-house DEM-based method for preparation of random packed beds. The resulting framework is verified in the simplified cases against available analytical solutions and correlations and is used to study an industrially-relevant case of ethylene oxychlorination performed in a tubular packed bed comprising CuCl2-coated catalyst carrying particles. In particular, we compare properties of three different industrially used catalyst carrying particles: Raschig rings, Reformax, and Wagon wheels
Plný tet:  HTM
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Smooth Transition Autoregressive Models
Khýr, Miroslav ; Zichová, Jitka (advisor)
The aim of this work is describing theory of smooth transition autoregressive models, namely LSTAR and ESTAR models. The essential part of the work is devoted to the derivation of tests for linearity against the alternative of the re- levant nonlinear model. There is also shown how to estimate the parameters of these models along with the selection procedure between the LSTAR and the ESTAR model. A simulation study was carried out, which deals with the power of linearity tests. At the end of the thesis, we applied the theory to some real data and we estimated the appropriate model for their representation. 1
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Smooth Transition Autoregressive Models
Khýr, Miroslav ; Zichová, Jitka (advisor)
The aim of this work is describing theory of smooth transition autoregressive models, namely LSTAR and ESTAR models. The essential part of the work is devoted to the derivation of tests for linearity against the alternative of the re- levant nonlinear model. There is also shown how to estimate the parameters of these models along with the selection procedure between the LSTAR and the ESTAR model. A simulation study was carried out, which deals with the power of linearity tests. At the end of the thesis, we applied the theory to some real data and we estimated the appropriate model for their representation. 1
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Smooth Transition Autoregressive Models
Khýr, Miroslav ; Zichová, Jitka (advisor) ; Cipra, Tomáš (referee)
The aim of this work is describing theory of smooth transition autoregressive models, namely LSTAR and ESTAR models. The essential part of the work is devoted to the derivation of tests for linearity against the alternative of the re- levant nonlinear model. There is also shown how to estimate the parameters of these models along with the selection procedure between the LSTAR and the ESTAR model. A simulation study was carried out, which deals with the power of linearity tests. At the end of the thesis, we applied the theory to some real data and we estimated the appropriate model for their representation. 1
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Dependence analysis of categorical data from banking
Khýr, Miroslav ; Zichová, Jitka (advisor) ; Mazurová, Lucie (referee)
Title: Dependence analysis of categorical data from banking Author: Miroslav Khýr Department: Department of Probability and Mathematical Statistics Supervisor: RNDr. Jitka Zichová, Dr., Department of Probability and Mathema- tical Statistics Abstract: The aim of this work is describing in detail the theory of the log - linear expansion and graphical models for random vectors with a discrete distribution. Such vector can be used for modeling categorical variables for example in a po- pulation of borrowers by a bank . We show how to estimate the probability of an individual category. We use a log - likelihood function. Independence graph can represent conditional independence of discretely distributed random variables. Using this theory, especially using deviance as test statistics, we can examine whether same data correspond to the selected graphical model. At the end of this work we apply the described theory to real data and determine the graphical mo- del best fitting the dependence structure in a database from banking. From this graph we can deduce which variables are dependent and which are independent. Keywords: Log - linear expansion, graphical model, log - likelihood function ,de- viance.
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