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Filtering antenna based on coaxial cavity resonators
Maro, Ivan ; Vrba, David (referee) ; Raida, Zbyněk (advisor)
Táto práca je zameraná na overenie funkčnosti navrhnutého konceptu laditeľnej filtračnej anténny. Anténa je navrhnutá tak aby spájala filtračnú a vyžarovaciu funkciu do jedného celku. Po odsimulovaní a overení správnej funkčnosti navrhovanej anténny [1] v elektromagnetickom simulátore, sa práca zaoberá možnosťami vylepšenia parametrov anténny. Na dosiahnutie vyššej smerovosti a zisku je navrhnuté riešenie kedy je na koniec filtračného vlnovodu pridaná pyramídová horn anténna. Obdŕžane výsledky sú následne použité pre navh antény integrovanej do subtrátu.
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Disposable plastic products on the Czech market
VRBA, David
The bachelor thesis deals with the issue of disposable plastic products. The first part deals with the consumption, negatives and positives of plastics. It also describes the handling of plastic waste and the content of the new Directive (EU) 2019/904 of the European Parliament and of the Council on the reduction of the impact of certain plastic products on the environment. The questionnaire survey is used to evaluate the consumption of disposable plastic products on the Czech market.
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Inhomogeneous cosmological models
Vrba, David ; Svítek, Otakar (advisor) ; Pravda, Vojtěch (referee) ; Žofka, Martin (referee)
In this work we study inhomogeneous cosmological models. After a brief review of applications of inhomogeneous solutions to Einstein equations in cosmology, we give a short description of the most widely used inhomogeneous cosmological models. In the second chapter we study in detail geometrical prop- erties of the Szekeres spacetime and we are concerned with the interpretation of the metric functions in different types of geometries. In the last chapter we model inhomogeneity in Szekeres spacetime. We derive formula for the density contrast and investigate its behaviour. We also derive conditions for the density extremes that are necessary for avoiding the shell crossing singularity in Szekeres spacetime. 1
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Effect of Ferrite Nanoparticles on the Thermal Exposure of Biological Tissue Phantom by Microwave Thermotherapy
Fišer, Ivan ; Vorlíček, Jaroslav (advisor) ; Vrba, David (referee)
Goal of this master thesis is describe effect of ferrite nanopartickles FeSi and FeH on the thermal exposure of biological tissue phantom by microwave Thermotherapy. Blank samples and the samples with increased concentration nanopartickles FeSi and FeH were prepared. Exposition was performed by open cavity resonator with 2, 45 GHz generator. Temperature profiles were taken by thermocamera Flir P25. Results of both types of samples were compared and were statistically interpreted. Agar samples with nanopartickles FeSi and FeH show higher increase of temperature, than blank samples. The differences are not statistically significant. Keywords: Microwave thermotherapy, nanopartickles
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Inhomogeneous cosmological models
Vrba, David ; Svítek, Otakar (advisor) ; Pravda, Vojtěch (referee) ; Žofka, Martin (referee)
In this work we study inhomogeneous cosmological models. After a brief review of applications of inhomogeneous solutions to Einstein equations in cosmology, we give a short description of the most widely used inhomogeneous cosmological models. In the second chapter we study in detail geometrical prop- erties of the Szekeres spacetime and we are concerned with the interpretation of the metric functions in different types of geometries. In the last chapter we model inhomogeneity in Szekeres spacetime. We derive formula for the density contrast and investigate its behaviour. We also derive conditions for the density extremes that are necessary for avoiding the shell crossing singularity in Szekeres spacetime. 1
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Effect of Ferrite Nanoparticles on the Thermal Exposure of Biological Tissue Phantom by Microwave Thermotherapy
Fišer, Ivan ; Vorlíček, Jaroslav (advisor) ; Vrba, David (referee)
Goal of this master thesis is describe effect of ferrite nanopartickles FeSi and FeH on the thermal exposure of biological tissue phantom by microwave Thermotherapy. Blank samples and the samples with increased concentration nanopartickles FeSi and FeH were prepared. Exposition was performed by open cavity resonator with 2, 45 GHz generator. Temperature profiles were taken by thermocamera Flir P25. Results of both types of samples were compared and were statistically interpreted. Agar samples with nanopartickles FeSi and FeH show higher increase of temperature, than blank samples. The differences are not statistically significant. Keywords: Microwave thermotherapy, nanopartickles
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