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Application of Electromagnetic and Acoustic Emission for the Diagnostics of Advanced Composite Materials
Trčka, Tomáš ; Chobola, Zdeněk (referee) ; Lokajíček,, Tomáš (referee) ; Koktavý, Pavel (advisor)
The subject of this dissertation is a theoretical and experimental study of electromagnetic and acoustic emission generated in the course of crack formation in solid dielectric materials. Theoretical part of this work is focused on the electromagnetic emission method, because it is related to a number of unsolved problems in the field of generated emission signals measurement, as well as in the field of the correct interpretation of obtained experimental data. Consequently, issues of emission signals detection by capacitance sensors and the transformation of crack primary parameters on the measured variables within the proposed transfer system have been dealt with. The results in this area were an extension of application range of the electromagnetic emission method on composite materials (especially on fiber reinforced polymer composites), identification and evaluation of the most significant emission sources in investigated composites and developing a methodology for evaluating of the crack primary parameters based on the measured emission signals waveforms in time and frequency domain. The experimental part of this dissertation was focused on a complex methodology for emission signals (including data from additional sensors) continual recording, processing and evaluation and for monitoring the response of stressed material to an applied mechanical load in real-time. Partial results from different research areas were also implemented into this methodology. This included the detection of emission signals, design and implementation of the appropriate measuring apparatus, analysis of measured signals in the time and frequency domain and advanced methods for processing and evaluation of measured data.
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Numerical Modeling of Periodical Structures
Nešpor, Dušan ; Bartušek, Karel (referee) ; Brančík, Lubomír (referee) ; Fiala, Pavel (advisor)
The thesis discusses the dynamic electromagnetic field on periodic structures. The author focuses on three principal types of resonant structures, considering their application possibilities. In general, these types can be individually defined as follows: materials exhibiting a negative refractive index of the incident electromagnetic wave; structures with gradual changes in impedance, characterised by their usability as reflectionless surfaces; and periodic structures able to conveniently shape the magnetic field distribution. Materials of the third group within the above-shown short list facilitate the fabrication of magnetoinductive lenses for nuclear magnetic resonance. The presented analysis of the properties of periodic resonant structures is mainly based on numerical models utilising the finite element method, and this approach is combined with both the derivation of the corresponding analytical relations and an experimental measurement of the non-radiating component of the electromagnetic field. The thesis includes a physical description of the basic elements of periodic resonant structures. Physical properties of the elements were examined in detail via numerical analysis. In the course of the research, the data acquired through this analysis and the related experimental measurement enabled the author to propose a method for optimising the most widely used resonant structures. Moreover, several new versions of resonant elements, structures, and fabrication techniques were also designed. The results obtained from the numerical analyses carried out to examine the central physical properties of the fabricated structure samples were all verified via the designed method for measuring the non-radiating component of the magnetic field.
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Spica/ Brno, Nove sady 49°11'20.3"N 16°36'29.4"E
Csanda, Denis ; Kisová, Barbora (referee) ; Nový, Vítězslav (advisor)
Design „micro-urbanism“ in designated area. Aim of this work is to find suitable development strategy of open city block. Bachelor‘s thesis adresses design of poly-functional building, including town hall and housing in city Brno. The main theme is to find maximal, yet optimal solution to site, which functions as parking space. The design tries to complete corner of designated city block, which will be part of future „south“ neighbourhood. The townhall and housing should function in harmony, which means the building will „live“ all-day long. The site is located in the node of historic centre and new planned neighbourhood. Between the site and neighbouring building will be parking garage tucked under the ground. Also there will be multifunction hall undergound center of the site. Design of the volume is complex and consists of pedestal and 3 towers. These towers volumes pixelate into the pedestal and open into the courtyard. Facade consists od unite form, which disolves and open in the upper levels.
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Design of a new version of a trolley and docking station for channel racks
Pastrnková, Markéta ; Vepřek, Jiří (referee) ; Vosynek, Petr (advisor)
The master's thesis deals with the analysis of the current version of the trolley and the docking station of the channel racks and the design of modifications. The theoretical part describes the components of the storage channel system. There is also explained principle of pallet storage in this part. In the following chapter, several variants of the design of the lifting mechanism of the lifting platform are elaborated. The work also presents static structural analysis of the current version of the trolley and docking station, parametric study and topological optimization of one of the components. Static structural analyzes were partially solved in the finite element software RFEM by Dlubal Software s.r.o company, and mainly in the software ANSYS Workbench 2020 R2 by ANSYS, Inc. company.
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Apartment building
Růžička, Filip ; Blažková, Vendula (referee) ; Daněk, Lukáš (advisor)
The subject of the bachelor's thesis is the processing of project documentation for a new residential building in Líšeň. The residential building is designed as a five-story fully basement structure. The underground floor contains collective garages and cellar compartments. The first above-ground floor contains rental spaces. The second, third, and fourth above-ground floors consist of residential units. A total of 30 residential units have been designed. The topmost fifth above-ground floor contains studios. The building has a flat roof with a parapet. The structural system of the building is primarily skeletal, connecting reinforced concrete monolithic walls that form the load-bearing part as perimeter walls. Another structurally significant element is the structural core with an elevator shaft. The horizontal load-bearing structures consist of reinforced concrete ceiling slabs. The entire building is founded on a white tank. The bachelor's thesis includes project documentation for the construction implementation.
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Static analysis of reinforced concrete walls with additionally made openings
Šimek, Ondřej ; Borzovič, Viktor (referee) ; Vítek, Jan (referee) ; Zich, Miloš (advisor)
The thesis deals with the implementation of additional openings in reinforced concrete walls from the point of view of structural analysis. Two types of walls are analysed: panel walls and infill shear walls. In the introductory part, the current state of knowledge in the methods of analysis of this issue is discussed and their advantages or shortcomings are pointed out. Several types of wall specimens with pre- or post-made openings with different types of reinforcement representing the state after an additional opening is made are proposed and their behaviour is experimentally and subsequently numerically verified. On the basis of the data obtained, methods are proposed for the structural analysis and the design of reinforced concrete walls with additional openings. For panel walls with openings, the analysis method using wall models is extended and the method of static assessment is specified. The method of analysis for infill shear walls with an opening using equivalent diagonal bar strut has been extended to take account for the reinforcement and its load state. The proposed structural analysis methods were applied to a real prefabricated house with an additional opening and to a hypothetical frame structure with a proposed structural intervention in its bracing system.
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Life
Maliňáková, Kamila ; Zálešák, Jan (referee) ; Mikyta, Svätopluk (advisor)
My bachelor´s thesis is called Life. My original intention was to paint a monumental, perfect picture, triptych of good, evil and something in between. Something like an altar of 2014 according to the model of the old masters. But at the beginning of my work there were a lot of doubts about my painting. It became more and more fabricated, which was confirmed by my teachers too. And therefore I decided to reassess my work and I found out, that more interesting than original painting is a backstage of my painting, the things, that hapeend around. And this is now a topic of my bachelor´s thesis - Backstage of my painting.
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Kindergarten
Vejr, Tomáš ; Nespěšný, Ondřej (referee) ; Pěnčík, Jan (advisor)
The thesis solves the project of a kindergarten in the field of inclination 7%. The kindergarten is located on the plots number 570, st. 373, st. 374 in the village Vrané nad Vltavou. The building has two floors and one basement. The kindergarten is for 60 children and for 11 employees. The building serves as a preschool institution for raising children. The supporting structure consists of a precast concrete frame supplemented in the basement by a cast-in-place wall and a foundation slap. External walls and partitions form sand-lime bricks Sendwich. The external walls are completed with Orsilt TF Profi mineral insulation th. 280 mm. The floors are made of prestressed concrete floor slabs Spiroll PPD 256 th. 250 mm supported by T and L primary beams. The building ends with a could extensive green roof. The slope and space for the blow-in insulation Climatizer Plus uses Steico Joist 400 I-beams. Windows are wooden frame Optiwin Purista and doors are Optiwin Entrada.
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The control unit of the door systems for public transport
Jablončík, Lukáš ; Vlachová Hutová, Eliška (referee) ; Friedl, Martin (advisor)
The topic of my bachelor´s thesis is to design a control unit of the door systems for public transport. The control unit is designed by using modern components. Their availability should be not less then ten years. The unit is controlled by a microcontroller ATMEGA and the motor is switched using the h-bridge. The control unit has ten programmable inputs and two switching outputs. PCB design is optimized for mass production. The result is a functional prototype of control unit.
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Study of the Selected Types of Sulphur Compounds in Beer and Brewing Materials
Mikulíková, Renata ; Ventura, Karel (referee) ; Ventura, Karel (referee) ; Čáslavský, Josef (referee) ; Márová, Ivana (advisor)
Much attention has been recently devoted to sensorially active substances affecting beer quality in the Czech Republic and worldwide. Among them, the heterocyclic and sulphur containing compounds play an important role, some of them with high sensorial activity even in extremely low concentrations. Trace amounts of these compounds, which can be frequently found in foods, participate in formation of their aroma and this effect can be generally evaluated as favorable However, in malt or beer it is true only to a limited extent and the presence of heterocyclic and sulphur containing compounds are in this respect assessed rather unfavorably. The aim of the present study was to provide a survey about of problems in the field of sulphur containing compounds in barley, malt and beer, to describe metabolic paths leading to their formation and to verify experimentally possibilities of their determination using modern analytical methods. Sulphur-containing amino acids are a natural part of barley, malt and beer and are precursors of the origin of volatile sulphur substances. The most frequently occurring sulphur amino acids, metionine, cysteine and homocysteine, were selected for analytical monitoring. The method of gas chromatography was used to determine sulphur-containing amino acids in barley, malt and beer. Prior to the analysis, sulphur-containing amino acids were derived and volatile N(O,S)-ethoxycarbonyl propyl esters were formed; they were subsequently analyzed using the gas chromatography with mass detector (GC/ MSD) and the gas chromatography with flame photo detector (GC/ FPD). Direct analysis of sulphur volatile substances is possible only rarely as they are found in the analyzed matrices (malt, beer) only in very low concentrations ( g/kg,l - ng/kg,l). Before the analysis, the analytes must be extracted from the matrix and concentrated. The modern analytical methods SPME (Solid Phase Micro Extraction), SPDE (Solid Phase Dynamic Extraction) and TDAS (Thermal Desorption Autosampler) were experimentally compared for the extraction and subsequent concentration of sulphur volatile substances. The method of gas chromatography with flame photo detector was used to determine sulphur volatile substances. Following volatile sulphur substances were monitored: dimethyl sulphide, dimethyl disulphide, dimethyl trisulphide, carbon disulphide, ethyl sulphide, diethyl disulphide, methionol, 3-methylthiophen, ethyl thioacetate, 2-methyl-1-buthanthiol. Only metionine was detected in significant amounts in the barley samples analyzed. Not only content but also dependence on a variety and locality were studied. Further, changes in methionine, cysteine and PDMS content during malting were followed. Results proved a significant decline in these substances content depending on the kilning temperature. Three types of fibers were tested for the analyses of the selected volatile sulphur substances in beer in the SPME method. PEG - a fiber with stationary phase Carbowax, PDMS - a fiber with stationary phase polydimethylsiloxan and a combined fiber CAR/PDMS - Carboxen and polydimethylsiloxan. Carbon disulphide, methionol, dimethyl sulphide, 3-methylthiophen and diethyl disulphide were detected with this method. Content of the other analyzed volatile sulphur substances was below the limit of detection. Further was tested usage the SPDE and TDAS methods. Both methods appear to be the suitable for the determination of volatile sulphur substances in beer.
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