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Thermodynamic Sensors Based on the Principle of Balance Equilibrium
Řezníček, Michal ; Husák, Miroslav (referee) ; Banský,, Juraj (referee) ; Szendiuch, Ivan (advisor)
This paper deals with the problem of monitoring the occurrence of the minority events in thermodynamic systems by using thermodynamic sensors based on the principle of balance equilibrium. The basis of this work is to find new sensor arrangement of thermodynamic sensors that allows work in a wide range of workloads of monitored system while maintaining the required sensitivity. Newly designed balance circuit for the sensor arrangement with four active sensors allows active setup of the default balance equilibrium and power matching of the sensor to its immediate surroundings in the system. By designing and optimization of balance circuit was achieved measuring the output response and its conversion to digital format. This enabled numerical analysis of output signal, algorithmic processing of the results and generate a feedback control signal to adjust the equilibrium conditions.
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Research and Development of Modern Emission MEMS Sensors
Pekárek, Jan ; Husák, Miroslav (referee) ; Vlach, Radek (referee) ; Vrba, Radimír (advisor)
The dissertation thesis is focused on research and development of modern emission MEMS sensors. The emission sensor based on the field emission from nanostructured materials represents innovative approach to pressure sensing. The nanostructures serve as electron emitter in an electric field between the cathode and anode in the pressure sensor. This electric field is constant and the change in ambient pressure causes the change of distance between electrodes, thereby the electric field is increasing. This intensity is proportional to the emission from the cathode made of nanostructured material. Changing the distance between the electrodes is caused by the deflection of the deformation element - the membrane, which operates the measured pressure. In the current state of the art an extensive research is carried out to find new nanostructured materials with good emission properties. Four nanostructured materials have been chosen and then experimentally prepared and characterized inside the vacuum chamber. For the simulation of diaphragm bending, the chamber is equipped with linear nano-motion drive SmarAct that enables precise changes of the distance between two electrodes inside the vacuum chamber. The computer model to predict the deformation of diaphragm was prepared in the simulation program CoventorWare. The behavior of diaphragm in a wide range of dimensions of the membrane, its thickness and the applied pressure are possible to predict. The dependencies of the current density on the electric field are plotted from the measured emission characteristics of nanostructured materials and thus characterized nanostructured materials can be compared. The dependencies are further converted by Fowler-Nordheimovy theory on the curve (ln(J/E2) vs. 1/E), whose advantage is linear shape. Basic parameters describing the emission properties of characterized nanostructured materials are deducted. Two methods for vacuum packaging of the sensor electrodes are designed. Anodic bonding technology and encapsulating using glass frit bonding are tested. To evaluate the bonding strength, the bonded substrates are tested for tensile strength.
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Methods for testing of analog circuits
Kincl, Zdeněk ; Vlček, Čestmír (referee) ; Husák, Miroslav (referee) ; Kolka, Zdeněk (advisor)
Práce se zabývá metodami pro testování lineárních analogových obvodů v kmitočtové oblasti. Cílem je navrhnout efektivní metody pro automatické generování testovacího plánu. Snížením počtu měření a výpočetní náročnosti lze výrazně snížit náklady za testování. Práce se zabývá multifrekveční parametrickou poruchovou analýzou, která byla plně implementována do programu Matlab. Vhodnou volbou testovacích kmitočtů lze potlačit chyby měření a chyby způsobené výrobními tolerancemi obvodových prvků. Navržené metody pro optimální volbu kmitočtů byly statisticky ověřeny metodou MonteCarlo. Pro zvýšení přesnosti a snížení výpočetní náročnosti poruchové analýzy byly vyvinuty postupy založené na metodě nejmenších čtverců a přibližné symbolické analýze.
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NEW PRINCIPLES OF GATE CAPACITANCE CHARACTERIZATION FOR SIGMA-DELTA MODULATORS
Sutorý, Tomáš ; Ďuračková, Daniela (referee) ; Husák, Miroslav (referee) ; Kolka, Zdeněk (advisor)
This thesis deals with the utilization of new principles of characterization of gate capacitances for sigma-delta modulators. Sigma-delta modulators are the integral part of sigma-delta analog-to-digital converters. The proposed new method is characterized by high resolution and modest requirements for laboratory equipment. It allows characterizing capacitances whose values are within the range which is used in sigma-delta modulators. The thesis contains description of the new method, the analysis of measurement accuracy and experimental results.
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The influence of the hub on discharge and efficiency of the swirl turbine
Husák, Martin ; Koutný, Luděk (referee) ; Haluza, Miloslav (advisor)
The aim is to determine by numerical modeling the influence of the hub on discharge and efficiency of the swirl turbine. The first part summarizes the theoretical knowledge about water turbines. In the main part is done hydraulic design of turbine, create model in Inventor, export geometry in Gambit and build mesh. Then it is described the solution methodology in Fluent, evaluation of computed data and their presentation in the form of tables and graphs
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Anyalyze of photovoltaic cell by noise diagnostic
Husák, Marek ; Sládek, Petr (referee) ; Vaněk, Jiří (advisor)
The master’s thesis deals with the noise diagnostic in the solar cells. Describes the main kinds of noises. The samples were quality and reliability screened using noise reliability indicators. The samples were surveyed by measuring the I-V characteristics, the noise spectral density as a function of forward voltage and frequency. It was calculated the noise spectral density as a function of forward current.
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Quality Management Tools
Husák, Martin ; Sivtseva, Aleksandra (referee) ; Fiala, Alois (advisor)
This bachelor‘s thesis is written in the form of literature search. Main goal is to map the tools and methods that are designed to improve and sustain the required level of quality. The text is divided into two chapters. The first chapter is devoted to the definition of quality, its historical development, basic concepts that help define quality and in the end is a list of so called fathers of quality. The second chapter describes the tools that are used for quality control. They are divided into two groups - the seven basic tools of quality, and seven new tools.
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Může průchod střevem žížal ovlivnit strukturu jílových minerálů: předběžné výsledky
Hušák, M. ; Frouz, Jan ; Had, J.
The effect of gut passage by three earthworm species (.i.Lumbricus rubellus, Dendrobaena octaedra, Dendrodrilus rubidus./i.) on the structure of ingested clay minerals was studied using X ray powder diffractometery. No differences were found in the peak's positions in diffraction spectra of clay spoil and clay in earthworm casts, indicating no changes in clay lamella inter-spacing. Differences were found in the peak's sizes, which seem to be caused by changes in preferential orientation of clay minerals during gut passage.
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