|
Connection between lattice models and continuum-mechanics models
Gottwald, Vít
The aim of this thesis is an investigation of lattice models in the context of Lebowitz-Penrose limit to provide a link between the underlying statistical mechanical models to the mesoscopic "continuous" description based on the nonlocal free energy functional. First, the basic formalism of statistical mechanics is introduced and an extended Blume-Capel model (r-model) defined. Then the mean-field approximation is discussed including a phase diagram of the classical Blume-Capel model. Fruther, the Lebowitz-Penrose theorem for the r-model is carried out from the scratch. All bounds are explicitly calculated. As a tool within the proof, the free energy functional is introduced and a transition from discrete to continuous variables is emerges. Finally, the basics of the van der Waals mesoscopic theory are discussed and a link with the original lattice model is established via the free energy functional.
|
|
Self-assembly and excited energy transfer in bacteriochlorophyll aggregates
Pospíšil, Petr ; Pšenčík, Jakub (advisor) ; Vácha, František (referee)
Bacteriochlorophyll c (BChl c) belongs among photosynthetic pigments. It is found in lightharvesting complexes of green photosynthetic bacteria in the form of self-assembled aggregates. It is possible to prepare BChl c aggregates also in vitro in aqueous solutions, in the presence of certain non-polar molecules (e.g. lipids or carotenoids). In this work, artificial light-harvesting antenna was prepared composed of BChl c and selected azulene derivative. The aggregation of BChl c with azulene enhances the absorption in the near UV region compared to BChl c. Fluorescence spectroscopy was used to study an efficiency of energy transfer from azulene to BChl c. The procedure used was based on fluorencence excitation spectra measurement, and a comparison with absorption 1-T spectra. The measurements were complicated by anomalous fluorencence of azulene, which occurs from the S2 state. Furthermore, the reference diode in the fluorescence spectrometer did not correct properly the signal in the near UV region, where azulene absorbs. The problem was partially solved by preparing the new correction files using selected laser dyes. Excitation spectra demonstrate the presence of the energy transfer from azulene to BChl c, however, it was not yet possible to satisfactorily quantify its efficiency.
|
|
Community trade mark and obstacles to its registration
Kačírek, Michal ; Pítra, Vladimír (referee) ; Růžička, Michal (advisor)
Resumé Community Trade Mark and Impediments to Registration Trademarks take important and still more preferred part of entrepreneur legal protection portfolio. The effects of European integration are partially visible in corresponding approximation of national trademark law of member states. The remaining barriers of cross- border undertakings in whole European Union were substantially mitigated by this new legal instrument, which grants its proprietor an exclusive right to prevent unauthorized use of the mark in trade without his consent. This diploma thesis deals with possible impediments to registration of Community trade mark. For an entrepreneur, it is crucial to know whether he may reasonably expect, that his trademark application will remain unchallenged. Therefore, the question must be raised on whether the mark is registrable as such. Since this is not the only nor the most frequent issue, the focus is made on the conflict with earlier rights as well. The systematization of this work is, to a certain extent, based on observation of respective parts of Council Regulation (EC) No. 207/2009 of 26 February 2009, dealing with absolute and relative grounds for refusal of a Community trade mark. The text also contains reference on important findings and decisions of Office for Harmonization in the...
|
|
Swing option valuation on electricity and natural gas markets
Uher, Martin ; Málek, Jiří (advisor) ; Fičura, Milan (referee)
Swing options had been part of natural gas market before its embedded option feature was appreciated. The flexibility of delivery is valuable because of characteristic features of energy commodities as non-storability, high frequency of events and seasonality. Swing options enable this flexibility. Holder of the option is allowed to react to market situation in flexible way and change the amount of delivery up or down in some known intervals. Total deviation from negotiated amount can't exceed some boundaries in case of "take-or-pay" condition. It is not unique general valuation form of such flexible contracts as swing options. General definition of Longstaff Schwartz Least Square approximation method (LSM) is provided at first. Then it is shown other standard valuation concept as finite difference method. It is also mentioned tree method and more complex dynamic stochastic programming method. Analysis of energy commodities time series of central Europe is done and it is shown example of LSM approach use in valuing swing option with underlying asset of base load electricity in Czech Republic.
|
|
Coherence transfer during relaxation in molecular aggregates
Olšina, Jan ; Mančal, Tomáš (advisor) ; Skála, Lubomír (referee)
We study the time dependence of the density operator of molecular aggregates in contact with thermal bath, to find a proper approximation for the description of a coherence transfer influence on this evolution. It is based on results of the computer program, written by the author of the work. The program uses three methods of evaluation - the solution of the convolution Quantum Master Equation, and solution of the derived Redfield equations in Markov and subsequent Secular approximations. The temperature dependence and dependence on other parameters of the model are discussed on the basis of the obtained numerical results performed on an example of a trimer. The influence of coherence transfer on time-evolution superoperator of the trimer is discussed as well. The reasons why the Markov approximation fails for a wide spectrum of parameters are given. It is concluded that it is not suitable for the description of coherence transfer effects.
|
|
Odhady algebraické chyby a zastavovací kritéria v numerickém řešení parciálních diferenciálních rovnic
Papež, Jan ; Strakoš, Zdeněk (advisor) ; Vlasák, Miloslav (referee)
Title: Estimation of the algebraic error and stopping criteria in numerical solution of partial differential equations Author: Jan Papež Department: Department of Numerical Mathematics Supervisor of the master thesis: Zdeněk Strakoš Abstract: After introduction of the model problem and its properties we describe the Conjugate Gradient Method (CG). We present the estimates of the energy norm of the error and a heuristic for the adaptive refinement of the estimate. The difference in the local behaviour of the discretization and the algebraic error is illustrated by numerical experiments using the given model problem. A posteriori estimates for the discretization and the total error that take into account the inexact solution of the algebraic system are then discussed. In order to get a useful perspective, we briefly recall the multigrid method. Then the Cascadic Conjugate Gradient Method of Deuflhard (CCG) is presented. Using the estimates for the error presented in the preceding parts of the thesis, the new stopping criteria for CCG are proposed. The CCG method with the new stopping criteria is then tested. Keywords: numerical PDE, discretization error, algebraic error, error es- timates, locality of the error, adaptivity
|
|
Passive houses - importance od certification and recovery of investment
Partlová, Zuzana ; Dvořák, Antonín (advisor) ; Hadrabová, Alena (referee)
In the present time, when prices of energy go up continually, we can hear more and more about the topic of energy-cutting. Important role in this sphere performs low-energy development. Passive houses, which are specific type of low energy houses, cut heat demand significantly. It means marked improvement with the view of energy saving, protection of the environment, but also quality of living. There is no doubt that these constructions bring numerous advantages, as evidenced by ever-growing number of passive houses abroad. Nevertheless, in the Czech Republic are very little passive houses. Partial intention of the thesis work is to highlight the importance of certification, which is able to contribute toward expansion of passive houses. The outcome of this part is proposal of the criteria for certification of passive houses in the Czech Republic. Principal aim of my diploma work is to compare passive house to common house in light of capital expenditures and operating costs and information about pay-off period of investment in low-energy buildings. Just matter of economic return is the most important criterion in decision making about construction of house or building.
|
|
Využití systému úspory energie KNX nejen v rámci osvětlení
Kunc, Josef
System of electrical installations KNX would be possible to cover up to whole number of different systems, which are determined to control less or most number of functions intended to good internal conditions of buildings are needed. But KNX system is only one standardized system in the world and therefore also the most extended system. The reason of it is in its specialization to control of all functions, which are needed to ensure the best internal conditions for people, not only in small, but in the biggest buildings too. KNX system cooperate without any problems with many other partial systems specialized to regulation of special function parts e.g. air-conditioning, ventilation etc. Because KNX is an open system, it cooperates with the other open systems, and there is possible to reach minimally energy consumption in whole building, but there is not influenced the comfort in all rooms of building. The consumption of all types of energy in every room is only according to instantaneous conditions required with persons. If is nobody there, the consumption is automatically limited. The result of cooperation of all components of KNX installation is energy saving in the range between of 30% to 60%, depending of level of supply with KNX.
|
|
Příklady odhadu stavu a parametrů pro lineární model s rovnoměrně rozloženými inovacemi
Pavelková, Lenka
In this contribution, state-space model with uniformly distributed innovations is introduced and the Bayesian state estimation proposed. The off-line evaluation of the maximum a posteriori probability (MAP) estimate of unknowns in the linear state-space model with uniform innovations reduces to linear programming (LP). The solution provides either estimates of the noise boundary and parameters or of the noise boundary and states. The on-line estimation is obtained by applying LP on the sliding window, i.e., by considering only the fixed amount, say partial, of the newest last data and states items. By swapping between state and parameter estimations, joint parameter and state estimation is obtained. The use of Taylor expansion for approximation of products of unknowns solves also the joint parameter and state estimation. Simulation studies help to get an insight on the potential and restrictions of these heuristic method. This contribution shares the experimentally gained experience with both these solutions of the joint state and parameter estimation.
|
|
Some aspects of the discontinuous Galerkin method for the solution of convection-diffusion problems
Hájek, Jaroslav ; Najzar, Karel (referee) ; Feistauer, Miloslav (advisor)
This work is concerned with the numerical solution of initial-boundary value problems for convection-diffusion partial differential equations. Three methods are studied and compared for this purpose: the combined finite element - finite volume (FE-FV) method, the discontinuous Galerkin finite element (DGFE) method of lines, and the spacetime discontinuous Galerkin method. The combined FE-FV method uses piecewise linear conforming finite elements for the discretization of the diffusion terms and piecewise constant FV approximation of the convective terms. The relation between the FE and FV approximations is determined by the so-called lumping operator. In the DGFE method of lines, the space semidiscretization is carried out by piecewise polynomial functions constructed over a triangular mesh, in general discontinuous on interfaces between neighbouring elements. In the space-time DGFE method, the approximate solution is piecewise polynomial in space as well as in time. We discuss both theoretical and practical aspects of the methods, and present numerical results for each of them. For the DGFE method of lines we derive an a posteriori error estimate.
|
guest ::
