National Repository of Grey Literature 236 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Measurment of Equivalent Circuit of Piezoelectric Resonator
Vomočil, Vojtěch ; Frk, Martin (referee) ; Kazelle, Jiří (advisor)
This theis deals with the general overview of the piezoelectric theory, focused both on the mathematical description and on the attributes of piezoelectric materials. It further focuses on the description of piezoelectric resonators with a more detailed explantation of their equivalent scheme and measurement methods of its single elements. The practical part of the thesis rests on the proposal of a measurement apparatus which will serve to measuring the equivalent circuit piezoelectric resonator elements. The realization of the apparatus and its functionality testing are described. In the experimental part of the thesis, the measured rates are processed and levels of the electric equivalent circuit elements of the used piesoelectric resonator for the basic and the two higher closest resonance frequency are set. The measured results are compiled into a standard measurement protocol. This thesis should place basics to the growing laboratory. It should also be a source of necessary theoretical and practical information for this lab.
Measurement uncertainty in diagnostics of insulating materials
Kamenická, Zuzana ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
This work deals with measurement capacity and dissipation factor of capacitor with real dielectric in frequency range 20 Hz to 30 MHz. Liquid and solid dielectrics are measured by LCR instruments and by test fixtures, both from company Agilent. Relative permittivity and loss number are calculated for different instruments settings. The general aim is to specify the influence of parameters as frequency, voltage, integration time and thickness of material on the uncertainties of primary and secondary quantities for measurement.
Heat transfer fluids for solar thermal systems
Hylský, Josef ; Frk, Martin (referee) ; Šimonová, Lucie (advisor)
This master thesis deals with the basic problems of solar thermal systems, which are using heat transfer medium. At the beginning this thesis describes basic components of the solar system, especially their meaning and attributes. Further in the thesis are mentioned heat transfer liquids for commercial usage which are used in those systems, their basic properties and dependence on temperature. There is described the physical nature of liquid viscosity and also ways how to measure them. The same is for measurement of liquid density and thermal conductivity. At the end was made measurement of dynamic viscosity of heat transfer liquids for commercial usage at different temperatures. In practical part of the thesis were mixed samples of alternative heat transfer mediums. It was measured their thermal and physical attributes, like for example density, dynamic viscosity and coefficient of volumetric expansion. Each measurement was compared and evaluated.
Mathematical transformation in dielectric relaxation spectroscopy
Brida, Marek ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
This labor treats the problem of dielectric relaxation spectroscopy in time domain, measurement of the absorption characteristics and their conversion to the frequency domain by creating a frequency depends of loss factor. Paper reports an overview of the most common mathematical transformation and approximation, which are used for this conversion and they also compare some of them. Mathematical methods used in this paper are Fourier transformation and Hamon approximation. Measured dielectric insulation is slot insulation type Isonom NKN 2039 and Isonom NMN 0967.
Analysis of composite with different proportion of filler
Brož, Přemysl ; Frk, Martin (referee) ; Rozsívalová, Zdenka (advisor)
This work consider with monitoring components of komplex permittivity at frequency section of electro-insulation material in process of wetting by dielectric relaxation spectroscopy.
Diagnostics of the perspective insulating liquids
Spohner, Milan ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
This work deals with the classification and diagnosis of electrical insulating liquids. Furthermore, the theoretical part describes the mathematical and physical principles of these liquids. The automated workplace was compiled with development environment VEE Pro for measurement of viskosity and control thermostat medingen and modifiable components for measuring complex permittivity in the frequency range. In the experimental part was carried out measurements of selected material parameters, investigated the effect of difficult conditions and made the mathematical evaluation of physical phenomena.
Comparison of different temperature sensors accuracy
Szotkowski, Radek ; Šimonová, Lucie (referee) ; Frk, Martin (advisor)
The Bachelor thesis deals with precise temperature measurument using various temperature sensors thermometers. Resistive temperature sensors, thermocouples and measurument uncertainty are studied. In practical part are mathematically and graphically presented results of measuring in three temperature points. Emphasis is placed on the accuracy of individual temperature sensors. The thesis also includes a laboratory task created for subject matters dealing with diagnosis.
Evaluation of water vapour permeability
Zemánek, Petr ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
The theme of this work is the knowledge of technical terminology and the laws of physics permeability materials in various industries. There are described basic properties of water vapor permeability and their meaning. This work refers to the possibility of measuring permeability in different application areas. The practical part involves the measurement and evaluation of water vapor transmission on selected samples.
Comparison of measured and simulated characteristics of temperature sensors
Vitek, Juraj ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
The aim of this work is to study all kinds of electrical temperature sensors, their categories, use and accuracy. I also made a functional simulator for metal electrical sensors with measurement.
Analysis of the properties of liquid crystalline materials
Bodeček, Martin ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
Master´s thesis covers introduction to the problems of materials with specific proprieties named liquid crystals. Theoretic part features primary fission these materials, theirs mechanical, electrotechnical and optical characteristics. Interesting chapter is description choice application including perhaps most interesting using liquid crystals - liquid crystal display. In this trend continues experimental part too, where there are first mentioned characteristics LCD, and after it alone metering capacitive characteristics display with active matrix. Main attention in experiment is however concentraded on evaluation frequency analysis of components complex permittivity regarding in plant temperature on submitted sample liquid crystals.

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