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Air ion measurement
Lazorka, Martin ; Roubal, Zdeněk (referee) ; Špinka, Jiří (advisor)
This thesis focuses on the basic problems of ions and the ionization itself, what influence ions have to the organism. Further it examines compensation of small negative ions in the residential environment. Introduction to measurement of ion concentrations. First measurements with the aspiration capacitor which is now the most commonly used measurement of ion fields. Measurement is focused on the concentration of air ions in the building, VUT FEKT T-10, then the concentration changes depending on the daily cycle, ventilation and concentration before teaching and after teaching.
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The design Spice models OA with verification their accuracy
Kučera, Tomáš ; Drexler, Petr (referee) ; Roubal, Zdeněk (advisor)
This bachelor thesis describes the design macromodels of operational amplifiers on the 5th level. Macromodel is designed from the measured parameters of the integrated circuit and created first Boyleho model and later model of multiple pole/zero. The proposed circuits are created using the entire library program OrCAD PSpice. The created macromodel can enter certain common parameters and simulate the manufacturing tolerance and mark modeled to a limited extent, other types of OA. The measured parameters are compared with results of PSpice simulation program and verified the accuracy of the method used for the design macromodel. Models are also suitably modified to simulate the noise voltage.
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The construction and design a transformer
Smejkal, Vít ; Steinbauer, Miloslav (referee) ; Roubal, Zdeněk (advisor)
After the general introduction to magnetism the work is further on concentrating on the construction of the transformator with the EI core. The work puts the emphasy especially on the calculation of the otherwise chartered data for the EI cores according to their size and the used material features suitable for the above mentioned core. Current transformer and its design is analyzed in next part. From the gained knowledge are than constructed the suitable procedures for the automated calculations, which are than realized in the Matlab environment.
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Low level measurement
Roubal, Zdeněk ; Lazar, Josef (referee) ; Sládek, Petr (referee) ; Steinbauer, Miloslav (advisor)
The doctoral thesis presents methods for low-level measurements, which are exemplified by the general measurement of air ion concentration. Within the first section, the author progressively identifies certain critical effects influencing the concentration of air ions, and these effects are to be considered in evaluating the uncertainty of the measured concentrations. Thus, the thesis aims to provide a systematic description of the procedures and requirements related to low-level measurements; the proposed description then involves a discussion of the process reliability requirements, namely the factors of repeatability, elimination of errors, and definition and describability of measurement uncertainties. Such methodology facilitates, among other activities, the long-term monitoring of air ion concentration in extreme environments, including caves or spaces characterized by high temperatures and humidity. The use of common methods for determining the air ion mobility spectrum is accompanied by a number of disturbing effects, such as spurious fluctuation in the concentration of air ions in time. The experimental section of the thesis describes the testing of different configurations of the measuring device (a collecting electrode and a polarization capacitor); at this stage, we seek the most advantageous distribution of the electrostatic field in the sensor – a Gerdien tube. The systematic suppression of the influence of spurious fluctuations in air ion concentration during the measurement of saturation characteristics is carried out with the least-squares numerical method (as a supporting element), a hybrid technique to describe and evaluate the experimental model. In the second part of the thesis, the methodology of low-level measurement is complemented with procedures for the measurement of freezing potential. This latter domain, as an overall experimental approach applicable during phase changes of the sample, has hitherto not been sufficiently characterized from the metrological perspective, in an up-to-date manner; several subregions of the said domain remain somewhat obscured and deserve significantly more attention. In the given context, this thesis systematically considers a problem where comparable measurement results produced by multiple authors are not available. The measuring methodology proposed herein was utilized in applied research to facilitate the fabrication of an apparatus for the experimental measurement of freezing potential in pre-defined samples; the obtained results then lead us to conclusions with respect to the evaluation of effects that cause differences in the measured data, and the results can be further compared with those obtained by other researchers investigating the given segment of the problem.
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Fuel consuptiom monitor for car gas-engine
Klásek, Tomáš ; Roubal, Zdeněk (referee) ; Drexler, Petr (advisor)
This work introduces readers into the principles of fuel injection and injection types in the modern combustion engines. The basic focus of this work is in the description of how the modern fuel injectors work. Then we describe the most important car sensors for our task. In the next part we will try to determine the normalized immediate fuel consumption by acquiring the data from the automobile. Finally, we will process the data by using an electronical platform and display them on a suitable indicator.
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The design of rf impedance meter
Wiesner, Jiří ; Hrabina, Jan (referee) ; Roubal, Zdeněk (advisor)
The first part deals with the basic methods for measuring an unknown impedance. After determining the parameters of the desired impedance analyzer method was chosen AC unbalanced Wheatstone bridge. As a source of harmonic signal has been selected direct digital synthesis circuit and measure provides the analog vector voltmeter. Subsequently, it is discussed the issue of determining the sign of the unknown phase impedance. The thesis describes the wiring of circuit AD8302 and circuit AD9958 direct digital synthesis for which it is also an example of the code. It discusses the design and simulation of a reconstruction filter. Finally there are the measured output voltage and spectrum synthesizer.
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Design and optimalization switched power source controlled by microcontroller
Smejkal, Vít ; Bartušek, Karel (referee) ; Roubal, Zdeněk (advisor)
This thesis deals with an introduction to the theory of switching power supplies and with properties of magnetic materials. Special attention is paid to nanocrystalline materials. It also discusses the issues of simulating the behavior of ferromagnets. The properties of commonly used ferrite material and nanocrystalline materials was measured. Using the created program for the design of forward converter is designed a switching power supply to verify its proposal. Design optimization is based on using a nanocrystalline core, which allows to reduce the operating frequency.
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Thermostat for measuring passive component controlled of AVR
Demjanics, Ferenc ; Koňas, Petr (referee) ; Roubal, Zdeněk (advisor)
The aim of this work is to familiarize with the design of the thermal test chamber to measuring passive components. Show features and involvement of selected circuits that ensure reliable operation of the device. For the realization of the role are the most important the Peltier cells and temperature sensors. But they can not work without the control unit. The control unit provides the necessary communication with each component and also with user. For this purpose we made a selection of suitable type of microcontroller and communication equipment (matrix keypad, LCD, buttons and LEDs). Subsequently was designed the algorithm to control the thermostat suitable for using in students training. The algorithm was written in the microcontroller in form of a program. There is also implemented a PSD controller in the program, which evaluates the data collected by a sensor. Then set the correct function of Peltier cells. After the thermostat was designed and realized, test measurements were performed and the results were documented and evaluated.
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Thermoregulator of piezoelectric crystal unit
Roubal, Zdeněk ; Vágner, Petr (referee) ; Kasal, Miroslav (advisor)
This thesis deals with thermal stabilization of crystal oscillators. A simple thermostat of piezoelectric crystal unit is designed in first part. Main emphasis is set to low input power. The second part deals with crystal oscillators with 102,5MHz and 10MHz frequency. They are simulated with Ansoft Designer software. Both of these oscilators are measured for short term and midterm frequency stability.
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Vyhodnocení připravenosti České republiky splnit požadavky na kvalitu ovzduší podle směrnic EU a Konvence LRTAP: Zhodnocení a optimalizace stávající staniční sítě a verifikace návrhu sítě ověřovacím měřením
Ústav informatiky AV ČR ; Český hydrometeorologický ústav, Praha ; Váňa, Milan ; Krejčíř, Pavel ; Horálek, Jan ; Brabec, Marek ; Pelikán, Emil ; Roubal, Zdeněk ; Sládeček, Jan ; Musialek, Jaroslav ; Jireš, Rostislav ; Elfenbein, Zdeněk ; Abraham, Jan ; Novák, Jiří ; Dvořáková, Miriam ; Kubizňáková, Jana ; Blažek, Zdeněk
Zpráva je rozdělena do jednotlivých etap: DU01-1.E3 Zhodnocení efektivnosti stávající sítě monitoringu mokré atmosférické depozice. DU01-1.E4 Návrh a zahájení ověřovacích měření v oblastech vymezených v DU02-2, kde je dle směrnice 96/62/EC povinné měření, ale kde měřicí stanice stávající sítě chybí. DU01-1.E5 Návrh optimalizované sítě monitoringu kvality ovzduší. DU01-2.E4+5 Optimalizace některých statistických vlastností měřicí sítě PM10 metodami prostorové statistiky. Analýza kovarianční struktury dat PM10. DU01-3.E4 Návrh systému provozu a obsluhy vzorkovačů PM10 a PM2,5. DU01-3.E5 Zhodnocení monitorování VOCs, POPs a těžkých kovů na stanici EMEP.
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