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Energy dispersive X-ray spectroscopy of doped PVDF fibers
Smejkalová, Tereza ; Papež, Nikola (referee) ; Sobola, Dinara (advisor)
Tato diplomová práce zkoumá flexibilní materiál k produkci elektřiny založený na piezoelektrickém polymeru Polyvinylidenfluorid (PVDF). Inkorporací piezoaktivní keramiky lze vlastnosti piezoelektrického polymeru PVDF významně zlepšit a převést na užitečnou elektrickou energii. PVDF byl vytvořen elektrostatickým zvlákňováním do vláken o tloušťce 1,5-0,3 µm a poté studován různými analytickými metodami. Tato práce nabízí popis elektrostatického zvlákňování, přípravu vzorků a teoretický úvod do analytických metod, kterým byly vzorky podrobeny. Morfologie a distribuce nanostrukturované keramiky do polymerní matrice PVDF byla pozorována použitím skenovací elektronové mikroskopie (SEM) a energiově disperzní spektroskopie (EDX). Pro tvorbu fáze a podrobné fázové složení byly vzorky charakterizovány infračervenou spektroskopií s Fourierovou transformací (FTIR). Práce také obsahuje analýzu s použitím Ramanovy spektroskopie, metody používané k identifikaci a porovnání chemických sloučenin. Elektrické vlastnosti byly studovány dielektrickou spektroskopií a je poskytnuta korelace se složením. Jednotlivé komponenty dotovaných vláken jsou charakterizovány a vyhodnocovány v souvislosti s jejich budoucím využitím v senzorech.
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Application possibilities of refractometer for liquids diagnostics
Macháč, Milan ; Kazelle, Jiří (referee) ; Frk, Martin (advisor)
This bachelor thesis focuses on application possibilities of refractometer for liquids diagnostics. The first part of the thesis focuses on the theoretical basics propagation of electromagnetic waves. The next section focuses on the measurement of refractive index, refractometry, a description of each type refractometers and short introduction to interferometry. The penultimate chapter is devoted to an application using a refractometer and what can measure and calculate. The last chapter is a practical part, there is described a calibration process, the measured values of the refractive index of liquids and evaluate the results.
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Monitoring properties of nanocomposites on base epoxy
Libra, Miroslav ; Rozsívalová, Zdenka (referee) ; Polsterová, Helena (advisor)
The present thesis deals with the study of nanotechnology in the field of composite materials (nanocomposites). Furthermore, the production, composition and electrical properties of these materials. Samples for the experiment are made of epoxy resin as matrix and titanium dioxide TiO2 as fillers with different benefits. Are the measurements the temperature dependence of permittivity, loss factor and internal resistivity.
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Application of nanofiller in electroinsulating materials
Mohyla, Petr ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
This project deals with calculation parts of complex permittivity varnish samples which is filled by nanoparticles of metal oxides. Opening of this project deals with theory of dielectric and effects in dielectric, theory of compounds and expressions in composite systems. Following topic is theory of nanoparticles and nanotechnologies and summarize adjusted results about this branch of knowledge. In practical part of work is include method which was use to make varnish samples filled by nanoparticles, prepare to measurement methods and whole results of measurement. In the end of work is analysis influence of filler particles each filler types to dielectric material and results verified mixture mathematical expressions.
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Modelling and behaviour of composite systems in AC electric field
Matoušek, Jiří ; Frk, Martin (referee) ; Rozsívalová, Zdenka (advisor)
This work deals with modeling of progression of dielectric variables and mixture formulas for solution of properties of composite materials in dependency on frequency. Theoretical part of the work explains physical principles of polarisation mechanisms and influence on dielectric constant with changing temperature and frequency. In theoretical part processes inside the composite material, which is in electrical field are described. The work contains summary of mixture formulas and methods of their derivation. Program for use in education is a part of the work. It allows modelling of progression of dielectric variables in dependency on frequency and Cole-Cole circle diagram. In mixtures it allows modelling of frequency dependencies of dielectric constant in accordance to Maxwell's, Bőttcher's and Lichtenecker's mixture formulas.
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Influence of filler particles size on parts of complex permittivity of composite
Mohyla, Petr ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
This project deals with calculation parts of complex permittivity varnish samples which is filled by ground mica with variety size of particles. Opening of this project deals with theory of dielectric and effects in dielectric. Following topic is theory of compounds and expressions in composite systems. In practical part of work is include method which was use to make varnish samples, their temperature stress and whole results of measurement. In the end of work is influence of filler particles each filler types to dielectric material and including coefficient which include size of filler particles to suitable mathematical expression.
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Axisymmetric antennas with metamaterials
Roman, Pavel ; Fiala, Pavel (referee) ; Raida, Zbyněk (advisor)
This project is focused on computer modeling of so-called meta-materials, and on the exploitation of metamaterials in the design of electrically small antennas. For modeling, COMSOL Multiphysics 3.3 was used. Simulations were focused on impedance matching of antennas. Antennas with metamaterials were compared with corresponding conventional antennas without metamaterial layers. The project does not investigate the creation of metamaterials; the project concentrates on their influence on crucial parameters of antennas. Next step this project is focused on optimalization this structure in program Matlab version R2009b. We used optimalization method PSO (swarms of particles) and results are comparing whit results calculating in COMSOL program.
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Modification of electroinsulating varnish with ground mica
Drápal, Aleš ; Frk, Martin (referee) ; Rozsívalová, Zdenka (advisor)
This master's thesis focuses on composite systems based on varnish combined with different filler ratios of micronized mica. The aim is to analyse impact of the filler on dielectric properties of the varnish, i.e. relative permittivity and loss factor as functions of frequency as well as charging and discharging currents as functions of time. Dielectric mixture formulas are applied on relative permittivity values. Calculated and measured values are compared.
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