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METHODS OF POLY-3-HYDROXYBUTYRATE EXTRACTION AND THEIR OPTIMIZATION
Pospíšilová, Aneta ; Plachá,, Daniela (referee) ; Kowalczuk, Marek (referee) ; Přikryl, Radek (advisor)
Poly-3-hydroxybutyrát (PHB) je biolodegradovatelný a biokompatibilní termoplastický polymer se širokou škálou potenciálních aplikací. Výroba PHB typicky zahrnuje fermentaci obnovitelných surovin bakteriemi. Získávání PHB z bakterií je však často náročné a neefektivní. V této práci jsou zkoumány a porovnány různé metody pro získání PHB, včetně digesce, mechanického rozrušení a extrakce. Jsou diskutovány různé optimalizační strategie, které lze použít ke zlepšení účinnosti izolace PHB. Experimentální a výsledková část popisuje snahy o zlepšení metod izolace, zejména kyselé a mýdlové digesce, které byly vybrány jako potenciálně ekonomické, bezpečné a šetrné k životnímu prostředí. Společně s našimi průmyslovými partnery jsme tyto technologie úspěšně otestovali v čtvrtprovozním měřítku a plánuje se další vývoj. Řešily se také možné aplikace a komercializace PHB. Bylo zjištěno, že PHB může nahradit některé mikroplasty v kosmetice a že toto úsilí má potenciál, protože přítomnost mikroplastů v běžných výrobcích je stále vysoká a na úrovni Evropské unie je plánován jejich zákaz. Dále byla studována tepelná stabilita PHB v závislosti na metodě získávání a byly vyvinuty dvě stabilizační metody, které umožnily použít PHB získaný digescí za použití mýdla v materiálových aplikacích.
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Heat-moisture and Heat Storage Properties of Heavy Structures of Sloping Roofs
Pilný, Ondřej ; Ostrý, Milan (referee) ; Novotný,, Marek (referee) ; Kalousek, Lubor (advisor)
The heavy claddings of sloping roofs are increasingly being incorporated into the common constructions of family houses, apartment buildings and other civic amenities. Thanks to the increasing demands for energy savings in the form of ever-tightening values of heat transfer coefficients and other thermal engineering requirements, these designs are the answer to how to achieve the requirements more easily. Furthermore, they are able to influence the passive thermal stability of interiors and thus solve not only the issue of overheating of buildings, but also to achieve energy savings in the case of thermal stabilization of the interior throughout the year. However, if there is a lack of understanding of these different constructions for heat-moisture and heat storage behaviour, there is a risk of the opposite effect and a risk of deterioration of interior thermal stability. Therefore, it is necessary to better understand these structures in terms of behaviour and the impact that their use has on the building itself. Also, it is desirable to understand the effect of changes in their partial material properties and of the composition itself on the functioning of heat-moisture and heat storage properties of compositions that use these materials.
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Effect of substantial grain refinement on microstructure and mechanical properties of precipitation hardenable magnesium alloys.
Hofman, Daniel ; Minárik, Peter (advisor) ; Janeček, Miloš (referee)
Properties of magnesium alloy WE43 and the effect of substantial grain refinement by ECAP were studied. The compressive strength test revealed a significant increase of yield strength after ECAP, resulting in yield strength of over 400 MPa after 8 ECAP passes. The material remained surprisingly ductile in both compression and tension. Thermal stability of the material was investigated via Vickers hardness test. The ultrafine-grained structure shows good thermal stability up to 300 řC, where the precipitates start to dissolve and grain size starts to increase, resulting in sharp fall of hardness. Annealing of the initial state showed best results for 210 řC where the precipitation hardening led to an increase in hardness up to ∼101 HV.
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Polyfunctional house
Kuklová, Jana ; Pilný, Ondřej (referee) ; Berková, Petra (advisor)
The main aim of the thesis is to design a new building of the mixed-use building in Brno. The building consists of two parts. One part consists of shops. The second part consists of offices and conference space. It is a building that has three floors above ground and one underground. In the basement there are a facilities and a garage. Shops are designed on the ground floor. There are offices on the second floor. Conference rooms are on the third floor. The building has a flat roof. The vertical load-bearing structures are designed from Porotherm ceramic blocks. In the core of the building, the vertical load bearing structures are designed as monolithic reinforced concrete walls. Columns are used in the building for the possibility of open space. The masonry of the basement consists of white bathtub. The floors are designed as folded from the Spiroll system. Internal non-load-bearing walls are designed from gypsum board with double cladding. The second part of the work deals with forced ventilation, cooling and central heating. In the third part of the project I deal with acoustics. The project was carried out in the Auotocad program. All constructions comply with valid standards and regulations.
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Flame retardant treated thermosets for composite materials used in transport industry
Novotný, Kamil ; Kučera, František (referee) ; Poláček, Petr (advisor)
First part of this bachelor‘s thesis contains a literature review, which describes basic mechanisms of flame retardancy, distribution of flame retardants into groups based on their composition and commercially available compounds. Experimental part studied the change of thermal stability and flammability of a thermoset resin with the adition of flame retardants. Change in mechanical properties of the resin was investigated as well. Epoxy resin was selected as a specimen of the resin group due to its excellent properties, which make it widely used in transportation industry. The main disadvantage of epoxy is its high flammability. The effect of two low cost, eco-friendly, easily applicable flame retardants was observed, namely expanded graphite and magnesium hydroxide. Materials were evaluated by a burning test, tensile test and thermogravimetric analysis. Overall, the additives caused a decrease in mechanical properties. Material with a combination of both compounds was found to be the least flammable, but had the worst mechanical properties.
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Synthesis of cyclodextrin derivatives for practical applications
Popr, Martin
Synthesis of cyclodextrin derivatives for practical applications Abstract The first part of this PhD thesis is focused on the synthesis of a series of monosubstituted tetraalkylammonium cyclodextrin (CD) derivatives. The emphasis was placed on the possible applicability of the synthetic process to multigram or even industrial scale. Monotosylation of the native cyclodextrins (-, -, -) on the primary side of the macrocycle afforded the starting materials. Derivatives with one cationic group were prepared by the reaction with aqueous trimethylamine. The reaction of the mono-Ts-CD with neat N,N,N'-trimethylethane-1,2-diamine or N,N,N'-trimethylpropane-1,3-diamine and subsequent methylation led to derivatives with the substituent bearing two cationic groups (PEMEDA- and PEMPDA-β-CD). Analogs bearing a moiety with three tetraalkylammonium sites were synthesized by reaction of mono-Ts-CD with bis(3-aminopropyl)amine with subsequent methylation. 1,3-Dipolar cycloaddition of mono-6- azido--CD with diaminoacetylenes followed by methylation led to analogs with a avariable distance of the charged substituent from the CD core. Majority of the presented reactions are straightforward, relatively high-yielding and the workup does not require chromatographic steps. The second part of the work is dealing with the...
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Modulation of interactions between interleukins and their receptors
Nepokojová, Tereza ; Schneider, Bohdan (advisor) ; Obšilová, Veronika (referee)
Scaffolds are proteins with high conformational stability, allowing us to implement multiple mutations into specific parts of the protein. Even with these mutations, the structural integrity of the protein is maintained as well as its physical-chemical properties. These mutations give the specific scaffold new properties. In most cases it is the binding specificity towards previously chosen target. The biggest advantages of scaffolds are their small size, stability, low-cost manufacturing, and easiness of preparation. Scaffold utilized in this thesis is unique for having two binging surfaces designed on which it can be mutated. Each of those two surfaces can be separately mutated to develop a binging site for two different proteins. In our case these mutations led to binding two nonidentical receptors of a human cytokine. Mutations are made with a use of yeast display, one of the methods of directed evolution. The main focus of this thesis is changing an expression system of the binding proteins from the yeast system to a bacterial one, their production and purification followed by characterization of those binding proteins using biophysical methods. These methods were used to evaluate structural and thermal stability, and binding affinity to both receptors of the beforementioned binding proteins....
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The investigation of an Al-Zr-Ti alloy prepared by spark plasma sintering of atomized powder
Molnárová, O. ; Málek, P. ; Lukáč, František ; Chráska, Tomáš ; Cinert, Jakub
The microstructure and mechanical properties of a powder metallurgical Al-Zr-Ti alloy was studied. Fine powder with a typical size below 50 ?m was prepared by gas atomization. The smallest powder particles with a diameter below 10 ?m exhibited a segregation free microstructure. Larger droplets were found to contain intermetallic particles rich in Zr and Ti. The gas atomized powder was consolidated by spark plasma sintering (SPS) at various temperatures ranging from 450 to 550 °C. During SPS the materials microstructure remained nearly unchanged and a fine grain size between 2 and 3 ?m was observed. All SPS samples exhibited a microhardness of around 90 HV. The annealing (1 h, 500 °C) of the sample sintered at the highest temperature (550 °C) resulted in a decrease of microhardness to 75 HV as a result of changes in the phase composition, the fine grain size was retained. Natural aging at room temperature was not observed.
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Effect of substantial grain refinement on microstructure and mechanical properties of precipitation hardenable magnesium alloys.
Hofman, Daniel ; Minárik, Peter (advisor) ; Janeček, Miloš (referee)
Properties of magnesium alloy WE43 and the effect of substantial grain refinement by ECAP were studied. The compressive strength test revealed a significant increase of yield strength after ECAP, resulting in yield strength of over 400 MPa after 8 ECAP passes. The material remained surprisingly ductile in both compression and tension. Thermal stability of the material was investigated via Vickers hardness test. The ultrafine-grained structure shows good thermal stability up to 300 řC, where the precipitates start to dissolve and grain size starts to increase, resulting in sharp fall of hardness. Annealing of the initial state showed best results for 210 řC where the precipitation hardening led to an increase in hardness up to ∼101 HV.
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