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Slit flow rheometer for magnetic and non-magnetic fluids
Železník, Tomáš ; Vimmr, Jan (referee) ; Roupec, Jakub (advisor)
In this thesis was designed, manufactured and tested the fourth evolution of a slit-flow rheometer with another necessary parts, eg. rheometer`s holder, drive frame and important jig tools. The rheometer is able to measure rheological properties of magnetic and non-magnetic fluids at very high shear rates, which commercial rheometers can not reach. It is designed for 200 bar pressure and maximum load 15 kN. The construction of the slit-flow rheometer with it`s holder and drive frame improves user friendliness, accelerates change of the fluid sample and expands research opportunities thanks to a big space for additional adjustments. It is possible to use different length of the slit and thanks to a changeable inserts it is possible to change parameters of the slit (roughness of the walls, wall material, thickness of the slit). A part of this thesis was focused on illation of necessary equations for planning calibration measurements. Aim of these measurements is to obtain minor pressure losses dependence on Reynolds number for specific slit.
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Preparation of chitin film
Debnáriková, Michaela ; Abdelrahman, Rasha (referee) ; Abdellatif, Abdelmohsan (advisor)
Predložená bakalárska práca sa zaoberá extrakciou, čistením, rozpúšťaním a prípravou filmu na báze chitín/ polyvinylalkoholu (PVA). Čistý chitín bol úplne charakterizovaný rôznymi metódami, ako je potenciometrická titrácia, FT-IR, TGA, XRD, SEM a pevná NMR. Rozpustnosť a čistota extrahovaného chitínu sa skúmala a hodnotila meraním obsahu proteínov, pomocou reológie a skúmaním času potrebného na rozpustenie. Filmy chitín / PVA boli pripravené použitím rôzneho pomeru roztoku chitínu a PVA. Merané a vyhodnotené boli morfológia povrchu, reologické a mechanické vlastnosti filmu.
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Optimized manufacturing of aluminium castings by using lost wax technology
Talanda, Ivan ; Horenský, Jiří (referee) ; Horáček, Milan (advisor)
Aim of this diploma thesis is to choose new pattern wax for Fimes a.s. foundry. New wax should substitute old not fully satisfactory pattern wax which caused problems in technological process resulting in increased number of rejects. New pattern wax should eliminate current problems and help foundry with producing large, thin-walled, high-quality castings. Numbers of pattern waxes supplied by world’s leading wax manufacturers were subjected to laboratory tests and pilot study. This diploma thesis is part of project Alfa TA01010766: „Research and development of production technology large, thin and high quality castings of aluminium alloys “
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Rheological properties of modified polymer-composite bone pastes
Hlináková, Kristýna ; Vojtová, Lucy (referee) ; Michlovská, Lenka (advisor)
Předložená diplomová práce je zaměřená na studium viscoelastického chování kostních past na bázi fosforečnanu vápenatého a vodného roztoku termosenzitivního triblokového kopolymeru, zlepšujícího tokové vlastnosti pasty. V teoretické části je zpracována stručná charakteristika cementů na bázi fosforečnanu vápenatého. Rovněž se zabývá charakteristikou reologických vlastností injektabilních kostních past. Součástí je také stručný přehled aditiv ovlivňujících právě reologické a mechanické vlastnosti past. Experimentální část je zaměřena na charakterizaci triblokového kopolymeru pomocí nukleární magnetické rezonanční spektroskopie a reologie. Dále byly připravovány modifikované fosfátové cementy, u kterých byly posléze studovány viskoelastické vlastnosti. Kostní pasta byla modifikována přídavkem adhezivních sloučenin (dopamin a jodičnan sodný) a antibakteriálním činidlem (selenové nanočástice). Analýza viskoelastických vlastností byla provedena reologickou analýzou, během níž byl primárně sledován proces vytvrzování a tixotropní chování jak nemodifikovaných, tak modifikovaných fosfátových past. Proces vytvrzování probíhal při teplotě 23 °C a 37 °C, imitující fyziologické prostředí. Morfologie fosfátové keramiky byla charakterizována pomocí rastrovací elektronové mikroskopie a velikost částic byla zjištěna pomocí laserového analyzátoru částic. Bylo prokázáno, že výše zmíněná aditiva mají pozitivní vliv na kinetiku procesu vytvrzování kostních past. Selenové nanočástice navíc vylepšily tixotropní chování polymer-fosfátových past. Z tohoto důvodu jsou tyto nové injektabilní kompozitní pasty vhodné pro miniinvazivní chirurgii. Díky aditivům, vykazujících adhezivní vlastnosti, mají potenciál uplatnit se při léčbě zlomenin. Stejně tak se nabízí možnost využít pasty při léčbě osteomyelitidy, a to díky možnému uvolňování antibakteriálních nanočástic.
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Preparation of hydrogels with the addition of grape pomace extract
Mojžíšek, Jan ; Veselá, Mária (referee) ; Kovalčík, Adriána (advisor)
The scope of this bachelor thesis is the preparation of hydrogels with antioxidant properties. These properties are achieved by the addition of grape pomace extract. The theoretical part of the thesis briefly summarizes the basic characteristics of the gels and describes the basic quantities in rheology. Furthermore, the classification, preparation and use of hydrogels are described. Attention is paid in particular to gels falling into the category of edible hydrogels. Information on antioxidants and matolins is also given. In the experimental part, extracts from grape pomace are characterized in terms of carbohydrate content, phenolic compounds and antioxidant properties. The extraction itself was carried out in different concentrated aqueous ethanol solutions. The extract with the highest total antioxidant activity, as determined by the ABTS method, was used for the preparation of the hydrogels. Agarose is used for the preparation of hydrogels. The change in the rheological properties of the hydrogels due to the addition of the prepared extracts was observed. The specific structures in the hydrogels were determined by FTIR.
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Study of properties of concrete with "green cement"
Matyk, Tomáš ; Dorazilová, Irena (referee) ; Bodnárová, Lenka (advisor)
The thesis focuses on collecting available information about possible ways of using and usage restriction of portland blended cements and portland cements with limestone for production of concrete. The experimental part of the thesis describes the behavior of portland blended cements and portland cements with limestone in aggressive environments. Furthermore, the thesis concerns the dependence of rheological properties of cement pastes of portland cements and portland cements with limestone on type of plasticizing additives.
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Usage of of common reclaimed asphalt in asphalt mixtures
Přívara, Jakub ; Coufalíková, Iva (referee) ; Dašek, Ondřej (advisor)
The bachelor thesis is focused on adding of RAP (reclaimed asphalt pavement) to the wearing asphalt courses flexible pavements. Specifically it is SMA 11S asphalt mixture. The theoretical part describes issues of ecology and recycling. The practical part deals with bitumen recovery from SMA mixtures with different added ratios of RAP and assessment of basic empirical and functional tests on the bituminous binder. The verification of properities of modified bituminous binder used in this quality SMA mixtures is also introduced.
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Reactions of HDPE in the melt initiated by peroxides
Hampapa, Břetislav ; Kučera, František (referee) ; Petrůj, Jaroslav (advisor)
The thesis deals with HDPE modification by crosslinking. In the theoretical part, data available in the literature were reviewed. Modifications of the selected HDPE copolymer grade were carried out in a kneading device Brabender using 25 ml chamber size. After having optimized process conditions, there were performed a series of experiments in dependence on concentration of the initiator. Reological properties of polymer samples were investigated by melt flow indexes measured under different conditions. Changes in crystallinity and melting temperatures were evaluated from DSC heat flow measurements. The samples meeting characteristics supposed were selected for measuring complex viscosity on the Rheometer AR-G2 TA and for testing some mechanical properties on the device Zwick.
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Vliv reologických vlastností nátěrových hmot na transparetní povrchové úpravy
Karadinović, Ana
The master thesis deals with the influence of the rheological properties of coating materials on the surface finishing properties. The main rheological properties which were analyzed are viscosity and flow time of the coatings. Water-based, wax and polyurethane coatings were used. The aim was to determine the effect of temperature and dilution of the coatings on their rheological properties. Used coatings were prepared with different properties and applied on different substrates. Laboratory tests of physical-mechanical, chemical and visual properties were carried out. The influence of the rheological properties of the coatings on the properties of the surface finishing was analyzed based on the results of the laboratory tests.
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