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Experimental setup for measurements of temperature dependecies
Riško, Miroslav ; Sedlák, Petr (referee) ; Majzner, Jiří (advisor)
The goal is to build an experimental setup for the measurements of temperature dependencies of the electrical and noise characteristics of PZT ceramic samples and QCM sensors. The functional older cryostat was used as central part and the experimental setup was completed using instruments for temperature and vacuum measurements and DC power supply. The software for the setup control was programed in Matlab enviroment.
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Measuring the Parameters of Piezo Energy Harvesters
Kunz, Jan ; Novák,, Martin (referee) ; Hadaš, Zdeněk (referee) ; Beneš, Petr (advisor)
This dissertation deals with the measurement of piezoenergy harvester parameters, in particular the measurement of their efficiency. The first part of the thesis summarizes important metrics for their comparison and reviews existing measurement systems for measuring harvester performance parameters. The measurement of harvester efficiency is simplified due to the complexity of power measurement and harvester efficiency is calculated from its parameters. However, this method is not accurate because it neglects mechanical losses and has a large measurement uncertainty. For this reason, the main objective of this work is to find a way to directly measure the harvester power input and thus measure its efficiency by definition, i.e. including mechanical losses. By analyzing the power flow in the harvester power chain, a way to achieve this goal has been found. Then, I have created an automated measurement system that allows to measure the harvester power parameters and also its efficiency including the determination of measurement uncertainties. In the last section, the performance, parameters and especially the two types of efficiency for commercially available harvesters are compared. As expected, the efficiency evaluated according to the definition come out smaller than in the case of its simplified version. However, this ratio varies widely for different harvester types, with the new efficiency being approximately one-third for PZT harvesters but only one-hundredth for PVDF harvesters. This significant difference shows that the different types of harvesters have large differences in mechanical losses, this difference could not be measured until now and thus remained neglected.
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Analysis of piezoelectric energy harvester for railway applications
Kubiš, Juraj ; Tofel, Pavel (referee) ; Hadaš, Zdeněk (advisor)
This master´s thesis deals with a piezoelectric energy generator, witch is a device that converts mechanical stress into electrical energy. It is small device that is mostly placed on vibrating structures in order to collect energy. By gluing this piezoelectric layer to the bottom of the rail, it would be a suitable power supply for the communication modules, while obtaining a sufficient amount of energy. These modules ale used as self-powered sensors stations with vision to monitor the condition of railway lines in more detail. The problem of these modules is their power supply, when the energy gain from the generators located on the railway line is insufficient. By acquiring a new energy source, this problem can be greatly simplified and lead to simpler inspection and earlier maintenance on railway lines.
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Smart materials for actuators
Brehovský, Patrik ; Hadaš, Zdeněk (referee) ; Huzlík, Rostislav (advisor)
The bachelor’s thesis “Smart materials for actuators” deals with appropriate use materials, named smart, in actuators. At the beginning, the thesis completes requests about actuators, which we need to set before making project. Next part is about the research of smart materials suitable used in actuators. The thesis continues with description of few more interesting smart materials. Thesis is ended with summary, which material is suitable to use for few selected projects and why.
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Pyroelectric effect in technical applications
Motlová, Tereza ; Tofel, Pavel (referee) ; Hadaš, Zdeněk (advisor)
The focus of this bachelor thesis is pyroelectric effect and its use for energy harvesting. Mathematical model of pyroelectric harvester was described, and then recreated in MATLAB-based graphical programming environment Simulink. Various applications of pyroelectric materials were researched, and their use as sources of electricity was evaluated.
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Measuring the Parameters of Piezo Energy Harvesters
Kunz, Jan ; Novák,, Martin (referee) ; Hadaš, Zdeněk (referee) ; Beneš, Petr (advisor)
This dissertation deals with the measurement of piezoenergy harvester parameters, in particular the measurement of their efficiency. The first part of the thesis summarizes important metrics for their comparison and reviews existing measurement systems for measuring harvester performance parameters. The measurement of harvester efficiency is simplified due to the complexity of power measurement and harvester efficiency is calculated from its parameters. However, this method is not accurate because it neglects mechanical losses and has a large measurement uncertainty. For this reason, the main objective of this work is to find a way to directly measure the harvester power input and thus measure its efficiency by definition, i.e. including mechanical losses. By analyzing the power flow in the harvester power chain, a way to achieve this goal has been found. Then, I have created an automated measurement system that allows to measure the harvester power parameters and also its efficiency including the determination of measurement uncertainties. In the last section, the performance, parameters and especially the two types of efficiency for commercially available harvesters are compared. As expected, the efficiency evaluated according to the definition come out smaller than in the case of its simplified version. However, this ratio varies widely for different harvester types, with the new efficiency being approximately one-third for PZT harvesters but only one-hundredth for PVDF harvesters. This significant difference shows that the different types of harvesters have large differences in mechanical losses, this difference could not be measured until now and thus remained neglected.
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Analysis of piezoelectric energy harvester for railway applications
Kubiš, Juraj ; Tofel, Pavel (referee) ; Hadaš, Zdeněk (advisor)
This master´s thesis deals with a piezoelectric energy generator, witch is a device that converts mechanical stress into electrical energy. It is small device that is mostly placed on vibrating structures in order to collect energy. By gluing this piezoelectric layer to the bottom of the rail, it would be a suitable power supply for the communication modules, while obtaining a sufficient amount of energy. These modules ale used as self-powered sensors stations with vision to monitor the condition of railway lines in more detail. The problem of these modules is their power supply, when the energy gain from the generators located on the railway line is insufficient. By acquiring a new energy source, this problem can be greatly simplified and lead to simpler inspection and earlier maintenance on railway lines.
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Pyroelectric effect in technical applications
Motlová, Tereza ; Tofel, Pavel (referee) ; Hadaš, Zdeněk (advisor)
The focus of this bachelor thesis is pyroelectric effect and its use for energy harvesting. Mathematical model of pyroelectric harvester was described, and then recreated in MATLAB-based graphical programming environment Simulink. Various applications of pyroelectric materials were researched, and their use as sources of electricity was evaluated.
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Smart materials for actuators
Brehovský, Patrik ; Hadaš, Zdeněk (referee) ; Huzlík, Rostislav (advisor)
The bachelor’s thesis “Smart materials for actuators” deals with appropriate use materials, named smart, in actuators. At the beginning, the thesis completes requests about actuators, which we need to set before making project. Next part is about the research of smart materials suitable used in actuators. The thesis continues with description of few more interesting smart materials. Thesis is ended with summary, which material is suitable to use for few selected projects and why.
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Spectroscopic Investigation of Lattice Dynamics in Multidomain Ferroelectrics
John Vakkechalil, Elizabeth ; Hlinka, Jiří (advisor) ; Hlídek, Pavel (referee) ; Hehlen, Bernard (referee)
Title: Spectroscopic investigations of lattice dynamics in multidomain ferroelectrics Author: Elizabeth Vakkechalil John Department: Department of Condensed Matter Physics Institution: Department of Dielectrics, Institute of Physics, AVČR, Na Slovance 2, Praha 8, 182 21, Czech Republic. Supervisor: Ing. Jiří Hlinka, PhD., Department of Dielectrics, Institute of Physics, AVČR., Na Slovance 2, Praha 8, 182 21, Czech Republic. Consultants: RNDr. Stanislav Kamba CSc., Ing. Ivan Gregora CSc. Fyzikální ústav AVČR, Na Slovance 2, Praha 8, 182 21, Czech Republic. Abstract: Lead based ferroelectric perovskites exhibit attractive physical and structural properties. Ferroelectric domains are known to have a very essential impact on dielectric and piezoelectric properties of ferroelectrics. Tailoring of domain structures allows to change the macroscopic symmetry of the material and to purposely modify its average tensor properties. Ferroelastic domains play also a key role in physics of epitaxial ferroelectric films. Here we studied signature of domain structure in PbTiO3 thin film grown by metalorganic chemical vapor deposition technique on different substrates, namely LaAlO3, MgO, NdGaO3, SrTiO3 (100), SrTiO3 (110), SrTiO3 (111) doped with 0.5% Nb and LSAT. Certain aspects of domain structure can be...
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