|
|
Proposal of Comunication Mix
Havlíčková, Romana ; Fiala, Roman (referee) ; Zich, Robert (advisor)
This bachelor´s thesis deal with assemblage of communication mix for the firm M-soft, the firm is engaged in internet services and sales computer technology. Thesis examines the firm, analyse of communication mix and environment and proposes useful combination of instruments of communication mix.
|
|
|
Design of class-D audio power amplifier
Fiala, Roman ; Götthans, Tomáš (referee) ; Brančík, Lubomír (advisor)
This semestral thesis describes class D low frequency power amplifiers and design of specific 2x100W class D power amplifier. The designed amplifier contains a second order sigma-delta modulator in which the quantization is controlled only by the delay of modulator components. This design does not include the clock generator which usually controls the quantization in sigma-delta modulators. This semestral thesis also includes design of a switched-mode power supply for the power amplifier and for the preamplifier. The PSpice program has been used for the design and verification of some sections of circuits. All designs have been built. Also basic parameters of completed circuits were measured.
|
|
|
Shortwave power amplifier
Fiala, Roman ; Vařacha, František (referee) ; Prokeš, Aleš (advisor)
This master’s thesis describes RF power amplifier design. The designed amplifier has been built. The first three chapters outline basics about radio frequency amplifiers. The basic theory needed for amplifier implementation is also described there. In the fourth chapter the power amplifier is designed. The design is based on the theoretical knowledge. Complete amplifier contains RF preamplifier, power amplifier and filters. The OrCAD PSpice, Ansoft Designer SV and EAGLE programs have been used for the design and verification of some sections of circuits. Measurement results of the built amplifier are in the fifth chapter. This thesis contains also the draft for laboratory exercise.
|
|
| |
|
|
TACR TJ04000365: Project EDIMO in the year 2021
Chaloupecká, Hana ; Fiala, Roman ; Jakubcová, Michala ; Kozohorský, Jan
The paper describes methods of work on the project TACR TJ04000365 in the year 2021. The paper focuses on the description of the models SWIFT and SPRAY. Furthermore, the creation of a middle-model, which was necessary to develop as one step from many others to be able to merge both models, is described. Finally, the paper is engaged in the trial-run of the merged models. The paper introduces the input parameters and the outputs in the form of concentration maps. The appendix contains sensitivity study of the model SWIFT in respect to the main inputs.
|
|
|
Investigation of new anode materials for methanol polymer fuel cells
Fiala, Roman ; Matolín, Vladimír (advisor) ; Sofer, Zdeněk (referee)
We investigated new types of anode catalysts for polymer membrane fule cell (PEMFC). Pt doped CeO2 thin lms were deposited by rf-magnetron sputtering on carbon nanotubes (CNTs) directly grown on GDL by using CVD. We observed considerable increase of speci c power by 1000 times and more in comparison with standard PtRu anode catalyst. For this new anode system we obtained the speci c power of 44.3 W/mg(Pt). The interaction of Pt with CeO2 layers with di erent substrates was investigated by using photoelectron spectroscopy. The results showed that platinum was in cationic state and the Pt2+/Pt4+ ratio was dependent of substrates materials. We also demonstrated that the performance of direct methanol fuel cell with Pt and PtRu catalyst can be dramatically increased simply by adding sodium hydroxide to methanol fuel. Cell voltage and power output characteristics were studied in dependence on current, temperature and concentration of sodium hydroxide. Endurance test was performed and the fuel cell exhibited stable response. Power density of 80.7 mW/cm2 was recorded for 2 M methanol/2 M sodium hydroxide fuel 30řC.
|
|
| |
|
|
Investigation of new catalysts for polymer membrane fuel cells
Fiala, Roman ; Matolín, Vladimír (advisor) ; Bystroň, Tomáš (referee) ; Napporn, Teko Wilhelmin (referee)
Fuel cells are a promising alternate power source of electricity. Despite of sig- nificant improvement that was reached by research throughout recent decades, the technology is not still ready to large scale commercial use. The catalyst of fuel cell (FC) should be still investigated due to fact that the only reliable functional catalyst is Platinum, a noble and expensive metal, which makes the use of this technology not competitive. In this thesis, investigation of Platinum doped ceria catalyst and its modification prepared by physical technique of deposition which is magnetron sputtering is presented. The catalyst was studied using standard sur- face analytic techniques (PES, SEM, AFM, XANES) as well as electrochemical measurement (CV, PEIS). The principal part of this thesis reports direct analyses of catalyst in fuel cell using an individually designed fuel cell test station. Con- sidering the high power density (PD) about 1 W cm−2 and substantially higher specific power per gram of Platinum (SP) 1.6 kW mg−1 in comparison with com- mercial Pt-Ru/Pt-C reference catalyst and additionally the relatively longtime stability, the sputtered Platinum doped cerium oxide based catalyst was found a suitable catalyst for PEM FC. Moreover, possible substitution of Pt and CeO2 by other elements was shown. Beside of...
|
|
| |
|
|
Investigation of new catalysts for polymer membrane fuel cells
Fiala, Roman ; Matolín, Vladimír (advisor) ; Bystroň, Tomáš (referee) ; Napporn, Teko Wilhelmin (referee)
Fuel cells are a promising alternate power source of electricity. Despite of sig- nificant improvement that was reached by research throughout recent decades, the technology is not still ready to large scale commercial use. The catalyst of fuel cell (FC) should be still investigated due to fact that the only reliable functional catalyst is Platinum, a noble and expensive metal, which makes the use of this technology not competitive. In this thesis, investigation of Platinum doped ceria catalyst and its modification prepared by physical technique of deposition which is magnetron sputtering is presented. The catalyst was studied using standard sur- face analytic techniques (PES, SEM, AFM, XANES) as well as electrochemical measurement (CV, PEIS). The principal part of this thesis reports direct analyses of catalyst in fuel cell using an individually designed fuel cell test station. Con- sidering the high power density (PD) about 1 W cm−2 and substantially higher specific power per gram of Platinum (SP) 1.6 kW mg−1 in comparison with com- mercial Pt-Ru/Pt-C reference catalyst and additionally the relatively longtime stability, the sputtered Platinum doped cerium oxide based catalyst was found a suitable catalyst for PEM FC. Moreover, possible substitution of Pt and CeO2 by other elements was shown. Beside of...
|
guest ::
