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Fading of the inoculation in graphitic cast irons
Doubrava, Jiří ; Jelínek, Radim (referee) ; Záděra, Antonín (advisor)
The bachelor thesis is focused on the structure and properties of cast iron with flake graphite. In the theoretical part the problems of crystallization of cast irons, grafting, methods of grafting of graphitic cast irons are discussed. In the practical part, the time course of grafting structure in cast iron with flake graphite was verified. Two inoculations were verified and the fading effect of the inoculations was also determined. For this purpose, samples were taken continuously at regular time intervals. To check the disappearance of the grafting effect, the method of turbidity test, thermal analysis, chemical analysis and then metallographic smear were chosen to observe the structure and evaluate the image analysis.
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Design of 90 degrees phase shift hybrid coupler
Ondrejka, Adam ; Čáp, Martin (referee) ; Kříž, Tomáš (advisor)
Aim of this bachelor's thesis is to search for best design of hybrid coupler with 90 degree phase shift while operating in the UHF band. Required power rating is 100 W. High frequency substrate, common FR4 substrate, microstrip lines, coaxial lines and discrete capacitors are used. Branchline coupler is selected and attempt is made to reduce its size while maintaining its properties. Ansys HFSS and Icepak are used for model building and simulations. Manufactured designs are measured and selected ones have their temperature monitored while loaded.
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Thermal management for mission CIMER
Borovička, Matej ; Lazar, Václav (referee) ; Götthans, Tomáš (advisor)
Táto práca sa zaoberá tepelnou analýzou CubeSatu, pričom vyhodnotenie a následná implementácia výsledkov do samotnej konštrukcie družice je veľmi dôležitá na zabezpečenie správneho fungovania všetkých jej komponentov. V prvej časti je opísaná problematika tepelnej analýzy a návrhy pre vesmírne aplikácie. Druhá časť je venovaná tepelnému návrhu nanosatelitu CIMER, ktorého úlohou je kultivácia cyanobaktérií na nízkej obežnej dráhe Zeme. Sinice majú veľmi špecifické požiadavky, pokiaľ ide o teplotný rozsah, v ktorom môžu prežiť. Táto analýza je preto veľmi dôležitá pre fungovanie celej misie. Práca opisuje vytvorenie tepelného návrhu v softvéri Systema Thermica, jeho následnú analýzu a vyhodnotenie. Nakoniec je model upravený na podmienky potrebné na prežitie siníc vo vesmíre.
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Nuclear power plant condenser design
Havel, Jaroslav ; Kracík, Petr (referee) ; Milčák, Pavel (advisor)
The submitted bachelor’s thesis deals with the design of a condenser for the new Dukovany II nuclear power plant with an electrical output of 1,200 MW. The specified condensation parameters reflect typical parameters of pressurized light-water moderated and cooled reactors of the same power and climatic conditions in the given location. From the assignment of the thesis and the research carried out, the following requirements for the designed device emerged: to ensure the condensation of steam in the secondary circuit in filmwise condensation mode, to comply with the maximum cooling water heating of 10 K, to install the tube bundle at optimum angle and to ensure the competitiveness of the product. For the selected concept with a four-body condenser, a thermal analysis was made and solved numerically by a fixed-point iteration method. The calculation was performed using the EES software. The results showed that a heat transfer surface area of 121,263.96 m is required to ensure failure-free operation of the condenser. Each condenser body consists of 31,400 titanium tubes with a cross-section of ( 22 × 0,5) mm and a length of 14,554 mm. A dimensional drawing is also attached.
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Thermal analysis of fuels
Šrámek, Zbyněk ; Hrnčířová, Michaela (referee) ; Moskalík, Jiří (advisor)
The main goal of this thesis is to introduce the field of thermal analysis as an independent scientific discipline. The first section is mostly informative and introduces into a concept of thermal analysis. The second part describes the most fundamental and essential methods of thermal analysis and the last section is focused on evaluating a real thermogravimetric experiment which deals with biomass sample.
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Comparative performance of late stream inoculants in grey cast iron using thermal analysis
Chyla, Ondrej ; Bouška, Ondřej (referee) ; Roučka, Jaromír (advisor)
This diploma thesis in the theoretical part deals with classification of cast iron, problems of gray cast iron production, methods of inoculation and valuation of the gray iron quality by means of thermal analysis. The aim of practical part was to investigate effectiveness of inoculation of two different inoculants using thermal analysis. In terms of mechanical properties, hardness and ultimate tensile strength were measured. Metallographic specimen were evaluating by means of image analysis software.
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Piston of a spark-ignition engine for 3-D printing
Zelko, Lukáš ; Dlugoš, Jozef (referee) ; Drápal, Lubomír (advisor)
The goal of the thesis was to design a piston manufactured by conventional method and subsequently adjusted one for additive manufacturing. Beside the designs, thermo-structural model was created for both pistons, considering maximal loading of the engine. Analysis evaluation showed the possibility of further application of the new technology in comparison to current one, within automotive industry.
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Utilzation of physico-chemical analyses in study on microbial stress-response
Slaninová, Eva ; Pekař, Miloslav (referee) ; Sedláček, Petr (advisor)
This diploma thesis deals with the utilization of physico-chemical analysis in study on microbial stress–response. The main content of this work was to propose and optimize techniques and methods which are generally used in different industries. Two bacterial strains, Cupriavidus necator H16 and its mutant strain Cupriavidus necator PHB-4 producing polyhydroxyalkanoates (PHA) under certain conditions, were used as model microorganisms. Initially, microscopic teques such as transmission electron microscopy (TEM), cryo scanning electron microscopy (cryo SEM) and atomic force microscopy (AFM) were proposed and tested for the characteriozation of morphological differences of bacteria. Furthermore, viscoelastic properties of bacteria were determined and compared by the oscillatory tests of the rheology method considering another type of samples. Thermal analysis methods, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) in particular, focused on water transport and behavior of intracellular water influenced by presence of the granules of PHB in bacteria. The last technique, utilized in the study, was dynamic and electrophoretic light dispersion during pH changes for characterization of the surface properties of bacteria such as size, zeta potential and the isoelectric point.
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Utilization of physico-chemical analysis in study on cellular water
Matejčíková, Eva ; Obruča, Stanislav (referee) ; Sedláček, Petr (advisor)
The bachelor´s thesis deals with the study of methods, available at the Faculty of Chemistry at Brno University of Technology, that can be used to determine physical and chemical properties of cell water. The main task of this work was to specify which of these methods are suitable to determine physical and chemical properties of water in the cell and the properties of water occuring close to the cell surface. Based on the background research the series of experiments were proposed and implemented. Subsequently, this work deals with the optimisation of methods that were defined as the applicable techniques to determine the properties of cell water.
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