|
|
Nerovnosti a jejich aplikace
TESAŘOVÁ, Jaroslava
This Thesis deals with mathematical inequalities, their use in mathematics and applications to thermodynamics. The main emphasis is placed on proofs of inequalities and solving examples. The following thing explains the mathematical concept such as norm or metric, needed to understand these procedures, and also some of basic concepts of thermodynamics. To understand this Thesis the knowledge of analysis and thermodynamics is required.
|
|
|
Hydrodynamic and thermal mode ling of reactive flow in the surroundings of intrusions
Jandová, Tereza ; Dolejš, David (advisor) ; Bruthans, Jiří (referee)
English Summary Intrusion of magma into the Earth's crust is associated with significant thermal perturbations, release of aqeuous fluids and formation of hydrothermal system. In order to better understand the feedback relationships between fluid flow, thermal evolution and permeability variations, we have modeled conductive and advective cooling of a shallow- crustal pluton using the SHEMAT software. Our model represents a two-dimensional cross section through the lithosphere with homogeneous material properties, whebery the heat and mass conservation equations are solved by finite difference method. We first calculate the stable lithospheric geotherm by emplying constant basal thermal flow of 40 mW m-2 and a constant surface temperature. Subsequently, we consider a rectangular magmatic intrusion emplaced at 5-10 km depth, which forms a contact aureole by conductive cooling. With time, a mushroom-like shape of the contact aureole is predicted. Inclusion of aqueous fluid flow into the model causes only a small alteration of thermal evolution mainly because the permeability is low and the fluid mass is negligible due to very low density under hydrothermal conditions. In addition to thermal effects, we have explored variations in hydraulic head in order to address the ensuing effects on the flow velocity. The...
|
|
|
Mathematical and computational modeling of shape-memory alloys
Benešová, Barbora ; Roubíček, Tomáš (advisor) ; Krejčí, Pavel (referee) ; Stefanelli, Ulisse (referee)
This dissertation thesis is concerned with developing a mesoscopic model for sin- gle crystalline shape-memory alloys including thermo-dynamically consistent thermo- mechanical coupling - here the term "mesoscopic" refers to the ability of the model to capture fine spatial oscillations of the deformation gradient by means of gradient Young measures. Existence of solutions to the devised model is proved in a "phase-field-like approach" by a scale transition from a microscopic model that features a term related to the interfacial energy; this scale transition from a physically relevant model justifies the mesoscopic relaxation. Further, existence of solutions is also proved by backward- Euler time discretization which forms a conceptual numerical algorithm. Based on this conceptual algorithm a computer implementation of the model has been developed and further optimized in the rate-independent isothermal setting; some calculations using this implementation are also presented. Finally, refinements s of the analysis in the convex case as well as a limit of the phase-field-like approach in this case are exposed, too.
|
|
|
Termodynamická analýza procesů v polymerní elektrolytické membráně palivového článku
Pavelka, Michal ; Maršík, František (advisor) ; Málek, Josef (referee)
Thermodynamic analysis of processes in electrolytic fuel cell membrane Michal Pavelka April 12, 2012 Abstract Hydrogen fuel cells1 may become a key technology of 21st century, and it is important to be able to describe their behavior, therefore. In this work we focus on hydrogen fuel cells with a polymer-electrolyte membrane. For the membrane we adopt an existing model2 . We for- mulate the model in the framework of the mixture theory which we develop similarly as has been done in the classical textbook of Mazur and de Groot3 . However, refining the concept of potential energy of a material point, we introduce new terms called internal potential ener- gies which enable us to describe macroscopic consequences of internal forces between water and polymer in the membrane and to describe the influence of gradient of surface tension of water in the membrane. We solve the model in 1D approximation. Consequently, we calculate the influence processes in the membrane have on efficiency of the fuel cell. 1 see for example Larminie, J. and A. Dicks. Fuel Cell Systems Explained. 2nd edition. John Wiley & Sons Ltd., 2003. ISBN 0-470-84857-X. 2 Weber, A. Z. and J. Newman. Transport in Polymer-Electrolyte Membranes I, II, III. J. Electrochem. Soc., 150 (7), A1008-A1015, 2003; 151 (2), A1311-A1325, 2004.; 151 (2), A1326-A1339,...
|
|
|
Thermodynamics of ideal cycles of IC engines in Matlab
Pavlíček, David ; Mauder, Tomáš (referee) ; Štětina, Josef (advisor)
Key aspect of this thesis is toolbox, which contains functions for calculate ideal combustion engine cycles. Thesis is divided into four parts. In the first part is briefly described history. The first chapter contains description of real combustion engine types. In the second part, which is covered by the second chapter, is located thermodynamic view. Third part is whole about MATLAB. From historical introduction through description of individual functions to example how toolbox can be used. In the last part is comparison of real combustion engine cycle with ideal one, which has been created by toolbox.
|
|
|
Basic thermal properties tester
Janečka, Marek ; Buršík, Martin (referee) ; Řezníček, Michal (advisor)
This work deals with metering heat feature of different types unyielding materials with the help of thermodynamic sensor. Here is above all surveyed, whether it is possible by the help of thermodynamic sensor mete heat conductivity and thermal resistance given to materials and subsequently accordingly to this to prove in part determine from measured results about what type of material walks.
|
|
|
Accurate positioning of pneumatic drives
Volf, Marek ; Nevrlý, Josef (referee) ; Marada, Tomáš (advisor)
Thesis starts with brief overview of the present role of pneumatic actuators. Further research is carried out in modelling and control of pneumatic actuators. A basic overview of thermodynamic laws is presented. These laws are used to assemble a mathematical model of the pneumatic drive. Subsequently the identification of model parameters is shown. A controller is propřed using fuzzy PID algorithms. Results are compared with the conventional PID controller.
|
|
|
Application of refrigerant cooling for air conditioning of buildings
Vlček, Petr ; Rubina, Aleš (advisor)
Diploma thesis deals with the problem of refrigerant cooling needs for air conditioning systems of buildings. Summary focuses on the theoretical basics and the physical nature of refrigeration and air conditioning technology. The consequences of split unite on microclimate in the room was experimentally tested and simultaneously investigated happenings associated to its activity. The aim is to unify the theoretical and experimentally obtained facts and apply them in the designing of air conditioning units. Design of air conditioning systems builds on my bachelor thesis, "Hot-air heating of gym", which subject was the ventilation system of gym.
|
|
|
Thermodynamics of ideal gases in Matlab
Zábojník, Jakub ; Klimeš, Lubomír (referee) ; Štětina, Josef (advisor)
In terms of bachelor’s thesis a toolbox of functions for basic computing in thermodynamics with ideal gases and their mixtures was built in environment of computer program MATLAB. Source code of these functions and their description are parts of this thesis. Among others fundamental characteristics of thermodynamic values and terms on which the creation of functions was built, and instruction for calling of functions are mentioned here. Functions in toolbox imaginary are divided to some groups. This dividing is results from principle of thermodynamic calculation. Functions from two neighbouring groups are directly tied together. For lucidity of function sequences and for functions usage and toolbox explanation the examples of using functions examples of functions usage in specific thermodynamic calculations.
|
|
| |
guest ::
