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Průša, David ; Žižková, Nikol (referee) ; Čermák, Jan (referee) ; Šuhajda, Karel (advisor)
In construction practice, microwave radiation is widely used for drying building materials, remediating damp masonry or sterilizing biotic pests that have invaded building structures. Another, albeit less frequent, use may be, for example, in accelerating the solidification of materials and components, where the time required to obtain the handling strength is reduced due to the effect of microwave radiation. The available scientific and technical literature indicates that some materials, such as brick elements, do not change their physical and mechanical properties when exposed to microwave radiation for moisture remediation, although this has not yet been sufficiently verified, and, in contrast, that there is a significant change in properties when microwave radiation is used to accelerate the setting of fresh mixtures, such as those containing a cementitious binder matrix. This thesis builds on many years of research in the area, complements and refines existing information, provides new insights into the mechanical and physical properties of commonly available building materials that have been exposed to controlled microwave radiation, and compares them with reference values. It also provides an opportunity for further experiments that can build on this research. The experimental research was conducted on two independent sets of samples. The first experiment was carried out on a set of clay brick samples, using tests according to European standards, and focused on the effect of microwave radiation on compressive strength and water absorption. The experimental specimens were exposed to moisture followed by exposure to microwave radiation for drying and then compared with reference specimens. The data from these experiments suggest that microwave radiation can be used for the rehabilitation of brick elements and there is no significant change in the resulting mechanical properties with respect to the initial condition. The second experiment was carried out on a set of concrete mixtures, where the curing process was accelerated using microwave radiation, and the mechanical and physical properties obtained were compared with those of reference specimens. The data from this experiment suggest that microwave radiation can be used to accelerate the curing of concrete specimens, thereby obtaining the handling strength in a relatively short time, but a reduction in the resulting strength can be expected compared with reference specimens.
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Design of repair material with reduced electrical impedance
Žáková, Karolina ; Černý, Vít (referee) ; Drochytka, Rostislav (advisor)
This bachelor's thesis focuses on designing a new composition of corrective material based on silicate with the aim of reducing electrical impedance. In the theoretical part, fundamental concepts necessary for understanding the topic will be described, such as terms related to conductivity, silicates, composites, and corrective materials in general. The experimental section includes the selection of raw materials, preparation, and testing of various compositions of corrective materials with different fillers. The impact of various additives on the electrical properties of the corrective material will be investigated, including its conductivity, resistivity, and cohesion. The final section summarizes and evaluates the achieved results.
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Magnetic nanoparticles with antibacterial properties: Synthesis, characterization and biological applications
Shatan, Anastasiia-Bohdana ; Horák, Daniel (advisor) ; Kaman, Ondřej (referee) ; Matějíček, Pavel (referee)
In response to the escalating global threat of antibiotic resistance, innovative strategies are imperative. This thesis focuses on surface-engineered magnetic nanoparticles (MNPs) with potent antibacterial properties, aiming to combat antibiotic resistance effectively. Specifically, uniform 16-nm Fe3O4 nanoparticles were synthesized via oleic acid-stabilized thermal decomposition of Fe(III) oleate in a high-boiling organic solvent. Optionally, 8-nm γ-Fe2O3 particles were obtained by coprecipitation of Fe2+ and Fe3+ salts in a basic medium. For the application of antibacterial MNPs in biological media, water-dispersible nanoparticles were required. Hence, original magnetic particles containing hydrophobic oleic acid (OA) coating were modified with silica using a water-in-oil reverse microemulsion. Subsequent modification with (3-mercaptopropyl)trimethoxysilane and decoration with silver nanoclusters yielded Fe3O4@SiO2-Ag nanoparticles. Additionally, neat Fe3O4 particles were coated with Sipomer PAM-200 containing both phosphate and methacrylic groups, facilitating attachment to the iron oxide and enabling (co)polymerization with 2-(dimethylamino)ethyl methacrylate and/or 2- tert-butylaminoethyl methacrylate. Furthermore, γ-Fe2O3 nanoparticles were rendered antimicrobial through modification with...
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Production technology of plastic porter for ammunition
Hejl, Dušan ; Kebrle, Ondřej (referee) ; Kandus, Bohumil (advisor)
Dissertation deals with solution of production of set component „plastic porter for ammunition“. Component is made from high-density polyethylene with business marking LITEN ML 77, suggested series of 3 000 000 pieces. On the basis of literary study of plastics injection problems and necessary calculations, there was proposed injection form. This form is solved by means of normalised components from company Meusburger. There was chosen injection machine from company Arburg Allrounger 370 S 700 – 170.
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The geosynthetics for roads
Kolková, Nela ; Hýzl,, Petr (referee) ; Stehlík, Dušan (advisor)
Bachelor thesis presents the material used for production of geosynthetics, the various types of commonly used geosynthetics and describes their specific functions and properties. It shows the processes of applications of geosynthetics and typical errors in these processes, foreign experience with the use of geotextiles and products of domestic manufacturers. In the practical section thesis compares the various proposals of geotextiles for various bedrocks. Including financial evaluation of individual proposals.
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Influence of polymers to reduce dust
Šubrt, Michal ; Mravcová, Ludmila (referee) ; Vávrová, Milada (advisor)
The main issue this bachelor thesis deals with the reduction of emit into the enviroment. A specific type of polymer compound from Canadian provenance will be tested for this purpose. The aim of this work will be the identification of positive characteristics of the polymer, and determine to the appropriate method of application. The above mentioned reduction of dust, stabilization of areas after application, possibly reduction of its permeability and increase of its maximum dry density will also by measured.
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Structural and electrical properties of PVDF-CNT composite
Misiurev, Denis ; Dallaev, Rashid (referee) ; Sobola, Dinara (advisor)
Electrospininig se osvědčil jako jeden z nejpopulárnějších a nejrozšířenějších způsobů výroby vysoce kvalitních vláken s požadovanými parametry. Kvalita a morfologie vyráběných vláken závisí na mnoha parametrů, jako je vlhkost, dávka materiálu, aplikované napětí atd. Omezení keramických piezomateriálů (křehkost, toxicita vzorků obsahujících olovo, obtížnost přípravy složitých tvarů atd.) vynutila výzkum v oblasti piezoelektrických polymerů. Jedním z nich je polyvinylidenfluorid (PVDF). polyvinylidenfluorid může by být připraven v různých formách: tenké filmy, objemové vzorky, vlákna. PVDF vlákna přitahují největší pozornost díky vysoké flexibilitě, nízké hmotnosti, mechanické stabilitě a chemické inertnosti. Vlastnosti PVDF vláken lze zlepšit pomocí doplňujících materiálů: keramické částice, kovové nanočástice, Graphicitové materiály jako jsou oxid Graphicenu nebo uhlíkové nanotrubičky (CNT).
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Heating Module for the Electrospinning Electrode
Lukesle, Václav ; Musil, Vladislav (referee) ; Pokorný,, Marek (advisor)
The thesis deals with the principal heating design of the electrospinning electrode. These electrodes are fed with high voltage (tens of kV), which is an essential part of the device for the nanofibres production. This thesis presents the research of possible solutions of the heating and also it analyzes some principles of the nanofibre production. Furthermore, the work presents electrical schematics and PCB of the heating module. The aim of this work is to propose such a solution of heating that makes spinning from melt realizable in the device for 4SPIN ® nanofibres production.
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Optimization of electrochemical sensor for detection in microvolume
Gajdoš, Libor ; Pekárek, Jan (referee) ; Prášek, Jan (advisor)
This thesis describes optimization and modification of standard thick-film electrochemical sensor to be able to be used for detection in microvolumes. In the theoretical part, the thick film technology is described. The work is then focused on the wettability of surfaces followed by introduction to electrochemistry and electro-analytical methods. In the experimental part, screen-printing of various types of thick film pastes on ceramic substrates for determination of their wettability and the following modification of the sensors with thick-film paste and with Parylene vaporization can be found, as well as the basic electrochemical measurements in microvolume using the modified sensor. Finally the results are summarized in conclusion.
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