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Functional foams with densit ygradient
Svatík, Juraj ; Figalla, Silvestr (referee) ; Jančář, Josef (advisor)
Vycházíme-li z lehčených přírodních materiálů, lze od porézních materiálů s gradientem porozity očekávat mechanické vlastnosti nadřazené konvenčím polymerním pěnám, a to díky jejich specifické architektuře. Tyto vlastnosti umožňují použití lehčených materiálů jako strukturních prvků. V této práci je popsaná příprava gradientních porézních materiálů pomocí laminování a/nebo 3D tisku. Provedeny byly statické a dynamické mechanické testy na obou kvazi homogenních a gradientně porézních pěnách poskytující experimentální podklad pro hypotézu deformační odezvy plynoucí ze strukturní architektury. Data se interpretovala užitím zavedených teoretických modelů. Naše výsledky vedly k závěru, že tyto teoretické modely odvozené od pěn s pravidelnou strukturou není vhodné aplikovat pro pěny s gradientem porozity, protože prokazují podstatně lepší mechanické vlastnosti než homogenně porézní pěny.
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Biomarker detection using electrochemical method with microfluidic chip
Klepáčová, Ivana ; Svoboda, Ondřej (referee) ; Neužil, Pavel (advisor)
The thesis is focused on the development of the electrochemical system with microfluidic platform for the detection of multiple biomarkers. It analyses the use of biomarkers for the early diagnosis of cancer. The theoretical part contains basic information about voltammetric methods and microfluidic systems. The practical part provides solutions to the microfluidic chips, including the description of the used materials, designs, methodologies of preparation and conclusions from the testing of the manufactured microfluidic systems. The thesis describes the lock-in electrochemical system which measures the response of 4 electrochemical cells simultaneously. For the electrochemical system measurements, an electrochemical chip consisting of 64 electrochemical cells was used. The results of the analysis include the processing of the system tests and detected voltammetric curves of the Fe2+/Fe3+ solution and cysteine.
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Automotive plastics with increased scratch resistance
Vida, Mikuláš ; Kučera, František (referee) ; Jančář, Josef (advisor)
The aim of this bachelor thesis was the investigation of changes of mechanical and rheological properties of nanocomposites based on PMMA, where filler was fumed silica of four types (different surface area and producer). The thesis focuses on the theoretical part of the current state of research, preparation and properties of nanocomposites. The solvent method was chosen for the preparation of nanocomposites, where silica was mixed with dissolved PMMA. Tensile mechanical properties were measured below Tg, while viscoelastic response was measured above Tg. Silica had not significant influence on the modulus below Tg, but above Tg (180 °C) both modulus, storage and loss, have increased with increasing silica content and with increasing frequency (0,1–100 Hz). The particle size and surface area of silica in a content of 1 % influenced storage modulus of nanocomposites more with respect to the content of 2 %. For samples containing 1 % showed that the significant role played particle size and surface area of silica. The greatest increase of storage and loss modulus of PMMA was reached for silica M-5 in content 1 %. All type of silica decreased tensile strength and strain with increasing silica content in the same way.
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Mechanical properties of fiber reinforced composites for automotive applications
Bayer, Adam ; Žídek, Jan (referee) ; Jančář, Josef (advisor)
Bachelor’s thesis deals with studying mechanical features of fiber composites. As a matrix was chosen PMMA and as reinforcement was chosen glass fabric. Theoretical part sums up contemporary issues of polymer composites in automotive industry such as their production techniques and methods of impregnation. In experimental part were prepared samples by block polymerization of 30 % solution PMMA in monomer with initiator by 65° Celsius warmth oath, when was fabric directly unfolded in pre-polymer solution. On these samples were executed tensile tests by testing device Zwick and these samples were compared with results of theoreticaly calculated values.
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Polymer nanocomposites with PMMA matrix
Kostková, Jana ; Žídek, Jan (referee) ; Jančář, Josef (advisor)
This bachelor thesis deals with s study of mechanical and viscoelastic properties of nanocomposites with PMMA matrix filled with different types of surface-modified silica, which differed by the specific surface area, surface treatment and particle size. Nanocomposites were prepared by dissolving, where nanofillers were injected into the dissolved matrix. Nanocomposite samples were tested in tensil and viscoelastic properties were determined till the softening point by dynamic-mechanical analysis (DMA). All types of nanofillers had almost no effect on tensile modulus of nanocomposites at room temperature (it was not reduced) one type of silica at a content 2 %, which was also confirmed by the DMA. The temperature DMA measurements showed that samples containing 2 % of silica were generally thermally more stable compared with nanocomposites containing 1 % of silica. Storage modulus of nanocomposites, except two ones, were similar or lower such pure PMMA to temperature 66 C, then the trend reversed. Loss modulus of all samples was one order of magnitude lower then the elastic modulus.
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Stress-strain analysis of skull implant using analytical and numerical solution methods
Sehnal, Dominik ; Borák, Libor (referee) ; Marcián, Petr (advisor)
This thesis focuses on stress-strain analysis of cranial implant. The research of literature available dealing with the problems of cranium implants and the solution of the stress analysis is incorporated. Furthermore, the basic information about an approach to the design and fabrication of medical implants is included. Subsequently, two ways of possible solution to the method of stress-strain analysis on an computational model of cranium (partially spherical shell) are introduced. These are analytical and numerical solution by using the finite element method in the Ansys programme. The calculated solutions of a particular type of task about deformation and stress are compared and evaluated with the solution acquired from the high level computational model of cranium with shaped irregular implant applied.
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Thin Film Electrodes for Electrochromic Devices
Macalík, Michal ; Kadlec, Jaromír (referee) ; Nováková,, Sabina (referee) ; Sedlaříková, Marie (advisor)
The work deals with the deposition of layers for electrochromic device with different methods. Transparent electrically conductive layer of SnO2 was deposited by pyrolytic decomposition of peroxostannate solution. Hydrogen peroxide in starting solution contributes to the oxidation process of growth layers and to increase the electrical conductivity. Active electrochromic layer of WO3 was electrolytic deposited from the peroxotungstic acid solution. Optimal deposition time and the optimal annealing temperature of deposited layers were found. Passive electrochromic layer of V2O5 was deposited using dip-coating method from peroxovanadate solution. A contribution of solution diluted with distilled water was investigated. Found results were used to construct complete electrochromic device with polymer gel electrolyte.
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The contrast curves determination for e-beam writer with Gaussian beam
Šuľan, Dušan ; Horáček,, Miroslav (referee) ; Krátký, Stanislav (advisor)
This work deals with technological process of structures creating by using of electron beam lithography. The main focus of the work is contrast curves of PMMA resist determination for electron beam lithography system Vistec EBPG 5000+ ES. Contrast curves are determined for different developers, developing times and the depths of resist. Sensitivity and the contrast of resist are determined from these contrast curves for each resist-developer system. Sensitivity curves are applied to the proximity effect correction on real structures, specifically the periodic diffraction gratings and then they are evaluated.
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