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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Vliv biokeramických aditiv na morfologii, fyzikální a biologické vlastnosti kolagenových nosičů pro tkáňové inženýrství kostí / Effect of bioceramic additives on morphology, physical and biological properties of collagen scaffolds for bone tissue engineering

Klieštiková, Nikola January 2018 (has links)
Diplomová práce se zabývá přípravou trojrozměrných porézních kolagenových kompozitních nosičů pro tkáňové inženýrství kostí a studiem vlivu přídavku biokeramických částic na morfologické, biomechanické a biologické vlastnosti. Teoretická část popisuje biomateriály a biokeramické částice používané pro nosiče v tkáňové inženýrství kostí a jejich metody výroby. Pokud jde o experimentální část, byly vzorky připraveny metodou lyofilizace. Testovaným materiálem byl kolagen typu I z prasečího a hovězího zdroje, který byl kombinován s hydroxyapatitem a směsí -fosforečnanu vápenatého s -fosforečnanem vápenatým v poměrech 1 : 1, 1 : 2 a 2 : 1. Byl hodnocen vliv rozpustnosti a velikosti částic na morfologii, mechaniku a biokompatibilitu nosičů. Přidání biokeramických částic změnilo morfologii vzorků. Velikost pórů se snížila, zatímco pórovitost byla ve všech testovaných vzorcích téměř stejná. Biokeramické částice také způsobily, že kolagenová matrice nosičů byla méně hydrofilní, a navíc dokázaly stabilizovat nosiče proti působení enzymatické degradace. Biomechanické vlastnosti vzorků byly testovány v suchém i mokrém stavu. V suchém stavu dosáhl nejvyšší pevnosti v tlaku čistý bovinní kolagenový nosič, naopak v hydratovaném stavu, dosáhly nejvyšší hodnoty vzorky obsahující biokeramické částice. Žádný ze vzorků nebyl cytotoxický a nejvhodnější prostředí pro buněčnou adhezi a proliferaci bylo v čistém bovinním kolagenovém nosiči a také v kolagenovém kompozitním nosiči s poměrem HAp : -TCP : 1 : 1.
22

Vliv povrchových úprav skleněných vláken na mechanickou odezvu GF/polyester kompozitu / The influence of surface modification of glass fibers on mechanical response of the GF/polyester composite

Janeček, Pavel January 2008 (has links)
The diploma thesis is aimed at an influence of surface modifications of fibrous reinforcements on mechanical properties at the fiber-matrix interface in fiber reinforced composites. Glass fibers were used as reinforcements and polyester resin was the matrix. The sample of composite consisted of polymer matrix in a form of cylindrical body placed on bundle of glass fibers. The design of the sample was constructed with respect to results of Finite Element Analysis (FEA). The tensile test using a materials testing machine (Zwick) was employed to evaluate adhesion at the fiber-matrix interface. Untreated glass fibers, fibers with commercial sizing, and fibers modified by deposition of plasma polymer film using Plasma-Enhanced Chemical Vapor Deposition (PECVD) at different deposition conditions were used for fabrication of composite samples. The fibers and composite samples were analyzed by Scanning Electron Microscopy (SEM) and Confocal Laser Scanning Microscopy (CLSM).
23

Modifikace elektroizolačního laku mletou slídou / Modification of electroinsulating varnish with ground mica

Drápal, Aleš January 2009 (has links)
This master's thesis focuses on composite systems based on varnish combined with different filler ratios of micronized mica. The aim is to analyse impact of the filler on dielectric properties of the varnish, i.e. relative permittivity and loss factor as functions of frequency as well as charging and discharging currents as functions of time. Dielectric mixture formulas are applied on relative permittivity values. Calculated and measured values are compared.
24

Analýza složené soustavy s různým podílem plniva / Analysis of composite system with different filler ratio

Mydlář, Marek January 2009 (has links)
This master’s thesis applies dielectric relaxation spectroscopy to analyse impact of climatic changes on dielectric properties of composite material samples (TSA 220S varnish combined with 60.030 mica). Experiments aim to analyse effect of mica composite mass ratio (0, 4, 8 and 16 % of mica), relative humidity (0, 33, 55, 65, 75 and 95 %) and temperature (23, 30, 40 and 50 C) on complex permitivity as a function of frequency.
25

Modifikace plniva cementotřískových desek alternativními vláknitými plnivy / Modification of the filler in cement-bonded boards with alternative filamentous fillers

Dywor, Michal January 2013 (has links)
The cement boards are commonly used as a filler fir or spruce chips-profit wood. The increasing demands for construction materials forcing technology to develop new types of composite materials using an alternative source of fillers. In this work in the context of theoretical knowledge about the specified fibers in composite systems are discussed properties of cement binder and filler for cement – bonded particleboards and alternative materials. The practical part describes the test methods designed recipes and then made boards of which were carved specimens intended for testing the properties of boards with alternative fillers.
26

Návrh cvičného letounu s tandemovým uspořádáním sedadel / Design of Trainer Aircraft with Tandem Seats

Dycka, Jan January 2008 (has links)
The diploma thesis deals with the project of composite constuction of aeroplane VUT 001 Marabu and its FEM stress-deformation analysis. The project of pilt´s cockpit is solved in the light of basic ergonomic requirements. Mass analysis, calculation and resulting selection of conclusive events of load are parts of the work. The results are applied on FEM model of fuselage and the state of stress in individual sections of composite structure are determined by the MSC Patran/Nastran system.
27

Vrstevnaté keramické kompozitní materiály - příprava, struktura a vlastnosti / Laminated Ceramic Composites - Deposition, Structure and Properties

Drdlík, Daniel January 2009 (has links)
The work was focused on the preparation of layered ceramic materials and their characterizations. The direct measurment of weight deposite for enhanced description of one component system was studied within this work. The kinetics of electrophoretic deposition obtained from theoretical calculation and from experimental values were confronted. It was prepared a lot of depositions for described kinetic of electrophoretic deposition with applied constant currents. The relative density and porosity were determined on the annealled and sintered bodies. The hardness measurments were performed on sintered bodies and then resulted values were confronted with the used currents. A ceramic composite based on Al2O3 and ZrO2 was prepared by using of precision describtion of electrophoretic deposition kinetic.
28

Návrh letounu VUT 022 s proudovým pohonem dle předpisu CS-22 / Design VUT 022 Aircraft with Jet Engine according to CS-22 Regulation

Matěják, Vladimír January 2009 (has links)
The diploma thesis deals with the design, load calculation and stress analysis of a composite wing construction of an airplane based on the construction of the airplane VUT 001 Marabu in order to fulfil conditions of CS-22 specifications. As a part of the thesis are basic mass, moment and aerodynamic characteristic of the airplane analyzed. Also the modification of the center part of the fuselage is designed in order to enable a jet engine instalation inside the construction.
29

Řezné síly při frézování vláknově vyztužených kompozitů / Cutting forces when milling fibre reinforced composites

Martének, Libor January 2009 (has links)
The thesis is focused on composite materials with a view to their classifi-cation, identification, usage, current trends in production and development and possibilities of effective machining. As a part of this thesis, there is an evaluation of experimentally measured values during technological testing of milling of a fibre reinforced composite with a polyester matrix reinforced by fiberglass. The technological testing was performed with a view to measure certain values, i.e. impact on machined material, working conditions for a tool and its abrasion equal to the values of components of cutting force. From the values obtained from the testing, a general analysis of cutting force when milling was created containing overall technical and economical evaluation.
30

Numerické modelování chování částicového kompozitu se sesíťovanou polymerní matricí / Numerical modeling of behavior of a particle composite with crosslinked polymer matrix

Máša, Bohuslav January 2011 (has links)
The master's thesis deals with the determination of macroscopic behavior of a particulate composite with cross-linked polymer matrix under tensile load. The main focus of thesis is estimation of mechanical properties of a composite loaded by tensile loading using numerical methods (especially finite elements method). Investigated composite is composed of matrix in a rubbery state filled by alumina-based particles (Al2O3). Hyperelastic properties of the matrix have been modeled by the Mooney-Rivlin material model. Different compositions of particles, their different shape, orientation and different volume fractions have been considered. For all these characteristics of composite numerical models have been developed. The damage mechanisms of the matrix have also been taken into account. Results of numerical analyses have been compared with experimental data and good agreement between numerical models with damage mechanisms of matrix and experimental data has been found.

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