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Measurement of Parameters of Piezoelectric Knock Sensors
Buchtík, Jaromír ; Málek, Petr (referee) ; Fialka, Jiří (advisor)
The first part of the bachelor thesis focuses on knock sensors. It deals with their use in industry on engines in biogas power plants, but also as part of internal combustion engines in vehicles. Furthermore, the work deals with the piezoelectric charge coefficient 33, as one of the main parameters to describe the piezoelectric element and the theory of its measurement methods. The second part of the work focuses on the measurement of individual elements. It begins with the measurement of simpler undamaged shapes, such as a disk or wafer. This was followed by the measurement of the ring-shaped element, which is the shape used in the sensor itself. Measurements were carried out both on bare rings and on screwed sensors or factory-sealed in plastic, from undamaged, to broken, chipped, cracked to loaded problems. The purpose of the work was to compare the measured data and find out whether it is possible to know whether the piezoceramic element in the sensor is damaged, or in what way
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Adaptability of electrospun nanofibers for bone-tissue engineering
Havlíková, Tereza ; Kaspar, Pavel (referee) ; Papež, Nikola (advisor)
The field of bone tissue engineering focuses on developing biocompatible scaffolds, which can successfully mimic the extracellular matrix of human tissue and provide the growing bone cells with the necessary mechanical support and adequate stimulation for proper growth and proliferation. This bachelor thesis describes the basic principles of tissue engineering with an emphasis on the area of bone tissue regeneration, examines current technological challenges and discusses prospective materials and technologies for the design of a compatible tissue scaffold. Electrospun nanofibers, their characteristic properties and adaptability are discussed in more detail. Based on the theoretical findings from the research, a design of a suitable scaffold created from the selected material for following seeding of bone cells, and the planned production procedures are presented. According to the design, the tissue scaffold is manufactured and a series of fundamental research analyses are conducted on it in terms of its structural integrity, chemical composition, wettability, crystalline phase content and cell adhesion. The results of these analyses inform the conclusion regarding the tissue scaffold’s adaptability for bone tissue engineering.
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Modal properties tuning analysis of a dynamic system with piezoelectric components
Skřivánek, Vladimír ; Sosna, Petr (referee) ; Rubeš, Ondřej (advisor)
In this diploma thesis, the possibilities of tuning the modal properties of a simple dynamical system using piezoelectric components are investigated. In the first part, the methods of passive, semi-active and active shunt damping are discussed. The second part is devoted to simulations of different techniques and shunt variants. From the results of these simulations, a particular shunt is selected and subsequently constructed. The conclusion of this work is an experiment with the constructed shunt on a real dynamic system. The obtained measurement data are finally compared with the outputs of the simulations.
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Biocrystallization as a new concept in development of piezoelectronics for use in biomaterials
Dobešová, Kateřina ; Plichta, Tomáš (referee) ; Sedláček, Petr (advisor)
This thesis focuses on biofilament methods and biocrystallization of bacterial cells producing polyhydroxyalkanoates, specifically the bacterium Cupriavidus necator H16. The main techniques used for cell orientation include spin-coating and acoustic waves. Biocrystallization was induced by temperature, osmotic, and acid stress. The degree of cell orientation was monitored by an atomic force microscope, and crystallization was determined by FTIR. Among other parameters, the thickness of the layers was evaluated using a profilometer. The amount of PHA in the bacterial cells was determined by gas chromatography. The preparation of crystalline ordered layers of biomaterials represents a route to piezoelectric biomaterials.
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Piezoelectric nanofiber materials for wearable electronics
Frolíková, Štěpánka ; Škarvada, Pavel (referee) ; Macků, Robert (advisor)
This thesis deals with the influence of production parameters on the morphology of PVDF nanofibers produced by electrospinning. Nanofibers are generally a widely used material, nanofibers are generally a widely used material, they can also have piezoelectric properties, which gives them a specific spectrum of use, eg in biosensors. The production of nanofibers was realized by electrospinning. A scanning electron microscope was used to examine the morphology and surface properties. The aim of this thesis is to compare the properties of PVDF nanofibers produced under different settings of production parameters.
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PiezoLegs motor in medical aplication
Plass, Petr ; Koláčný, Josef (referee) ; Ondrák, Tomáš (advisor)
The Bachelor’s thesis is focused to explain of basic conceptions of piezoelectric motors including principles of piezoelectric effect. It is analysed velocities of movement of PiezoWave motor during loading and he is valued supply voltage of used demo driver. Then it is considered of drive with stepper motor and DC motor, it is compared them with piezoelectric motor and chosen the best alternate for the drive of a pump of the artificial heart. Then it is introduced with working in a program i-Speed 2 to analyzing of shots catch by the high speed video camera and it is given a basic manual to connecting, setting and programming of the drive connected to the EPOS P driving unit.
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Proposal of piezo-generator inside button
Kučera, David ; Houška, Pavel (referee) ; Hadaš, Zdeněk (advisor)
This bachelor’s thesis deals with proposal of piezo-generator inside button. There are described types of piezo-generators, explained piezoelectric effect, types of piezoelectric material with focus on piezoceramics. The properties of piezoelectric ceramics are described. Proposal of piezo-generator inside button is described at the end of this thesis.
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Surface acoustic wave filter
Tichý, Jakub ; Dědková, Jarmila (referee) ; Raida, Zbyněk (advisor)
The theoretical part of this thesis deals with principles and characteristics of the surface acoustic wave filter. It explained the principle of magnetostriction and piezoelectric effect, which uses a filter. In the practical part in the program Comsol Multiphysics are made three simple models of SAW filter. Some modes are founded and are compared to previously known results. In the next phase of project is further studied using the parametric analysis. In the last phase of project is applied global optimization PSO at admittance characteristic from simple 2D structure. The results are compared with the commercially produced devices.
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Preparation and optimization of electrospun materials suitable as electricity generators
Pokorná, Romana ; Holcman, Vladimír (referee) ; Tofel, Pavel (advisor)
This master's thesis is focused on energy harvesting and is divided into two parts: theoretical and practical part. The theoretical part of the thesis contains the dielectric parameters, the meaning of the piezoelectric and triboelectric effect and the principles of electric energy gain in energy havesting. The last chapter of the theoretical part is devoted to various electrospun materials suitable for energy harvesting. The practical part of the work deals with nanofibers as an energy generator and describes their dielectric parameters. In this part the relative permittivity and loss factor of selected types of nanofibers are measured. Also the triboelectric nanogenerator is made and it's properties are measured.
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