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Study of particles of various cosmetic pigments
Cerevatova, Kristina ; Opravil, Tomáš (referee) ; Zemanová, Jana (advisor)
The main focus areas of this master thesis include the writing of a literature review, which contains an overview and segregation of pigments which are used in the preparation of cosmetic products. The thesis is focused on the properties and characterization of pigments for use in cosmetology. The following focus is on legislation, more specifically on pigments that the cosmetic industry allows, limits and does not allow. The main part of this thesis is an overview of methods for the characterization of pigments. The practical part deals with the characterization of particles of selected cosmetic pigments by applying methods for determination of color, elemental and phase composition, particle size and morphology. The thesis is concluded by evaluation of the achieved results.
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Study of FRP for concrete reinforcement
Blahová, Aneta ; Prokeš,, Jan (referee) ; Bodnárová, Lenka (advisor)
The diploma thesis aims to analyze bent FRP reinforcements. It describes the method of production of bent FRP reinforcement, examples of application of FRR reinforcement in structures and mentions aggressive influences influencing the durability of FRP reinforcement. Furthermore, an experiment is proposed to monitor changes in straight and bent FRP reinforcement stored in an aqueous environment at 20 °C and an alkaline environment at 20 °C and 40 °C. The output of the diploma thesis is the evaluation of changes in mechanical properties and durability. The condition of the FRP reinforcement is documented using optical and electron mocroscopy.
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Influence of nozzle angle on gas pressure distribution in the nozzle according to Prandtl's theory
Dostalová, Petra ; Maxa, Jiří (referee) ; Šabacká, Pavla (advisor)
The thesis is focused on issue pressure distribution in the nozzle while pumping the differential pumped chambre of an environmental scanning microcope. The main task of the thesis is to find suitable design of this nozzle respect to Prandtl`s theory. In the theoretical part, there are presented microscopy as science. Afterwards the thesis is focused on environmental scanning electron microscopy and its problem and vacuum system, computer program used for preparation of simulation and study that the experimental part is based on. The experimental part evaluates the results of physical-mathematical analysis of the flow inside and behind the Laval nozzle in the experimental chambre. The results are the basis for the optimal proportions of this nozzle.
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Reduction of brass corrosion layers using hydrogen plasma
Řádková, Lucie ; Grossmannová, Hana (referee) ; Krčma, František (advisor)
The main topic of this Diploma thesis is the application of low-pressure low-temperature hydrogen plasma for the treatment model samples of rusted brass. Plasmachemical treatment of metallic artifacts is a relatively new way how to remove corrosion of artifacts. The temperature of an object should not exceed 150 °C during the treatment. Corrosion layers were prepared in an ammoniac corrosion atmosphere. The corrosion formation took two weeks. Energy Dispersive X-ray Microanalysis has shown that the corrosion layer was formed by carbon, oxygen, copper, zinc, and lead. The corrosion layers were blue-colored with white crystals on the surface. Except those two colors, brown color was observed on corrosion layers, too. The plasma reactor was a quartz tube with outer copper electrodes and supplied by the RF source of 13.54 MHz. The reactive atomic hydrogen was formed in plasma discharge. This atomic hydrogen reacted with the corrosive layer containing oxygen. This reaction created an unstable OH radical, which emitted light in the region of 305–320 nm. This radiation was detected by the optical emission spectroscopy and it was applied as process monitoring quantity. Rotational temperature and intensity of OH radicals were determined from obtained data. The sample temperature was measured by thermocouple installed inside the sample volume. Rusted samples were treated by low-pressure low-temperature hydrogen plasma. 16 samples were treated at different conditions – plasma power was 100 W, 200 W, 300 W, and 400 W at continuous mode and pulse mode with duty cycle of 25 %, 50 %, and 75 %. The pressure was between 140–160 Pa at hydrogen flow rate of 50 sccm. Samples after plasmachemical treatment were grey colored with white crystals on their surface. Corrosion layers were removed by spatula. The corrosion layers of some samples were easy removable, some others were difficult. Energy Dispersive X-ray Microanalysis, which was carried out after the treatment of 2 selected samples (400 W, 50% pulse mode and 400 W, 75% pulse mode), showed different amounts of carbon, oxygen, copper, zinc, and lead compared to the rusted sample. Other elements in the treated layer were silicon, sulfur, chlorine, and fluorine.
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Comparison of flow conditions in the gas detector used in the aperture and screen
Hubáček, Jiří ; Špinka, Jiří (referee) ; Maxa, Jiří (advisor)
The first part of the thesis deals with electron microscopy and physical model fluid flow. In the next part, a three-dimensional model is created in programme SolidWorks. It is the model of scintilating detector with aperture or screen with three hundred little apertures. These models are submitted to analysis focusing on investigation of the gas flow at different pressure in chamber of specimen ESEM using Cosmos FloWorks system. The results of the analysis of both apertures variants are compared with the request to minimize the pressure in the trajectory of the secondary electrons as well as in the chamber of specimen.
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Characterisation of Nanostructure Deposited by PVD and CVD Technology
Fořt, Tomáš ; Boušek, Jaroslav (referee) ; RNDr.Vilma Buršíková, Ph.D. (referee) ; Sobota, Jaroslav (advisor)
The thesis deals with mechanical properties of thin hard wear-resistant coatings. The work presents a method of dynamic testing of thin hard coatings on a newly constructed prototype of impact wear tester. It provides a comparison with standard methods of layer testing and presents new experimental results of dynamic impact wear test of the coatings. Finally, the thesis covers preparation techniques of thin film systems deposited on various substrates and their characterization using optical and electron microscopy.
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Using Computer Aided Engineering for analyse the detector
Novotný, Marek ; Špinka, Jiří (referee) ; Maxa, Jiří (advisor)
This diploma thesis deals with electron microscopy. Examined equipment is environmental scanning electron microscope (ESEM), namely scintillation a detector of the microscope. There is solved the influence of the profile of holes in diaphragms to the resulting pressure and gas flow on the path of secondary electrons at the detector. Introductory part of thesis informs about microscopy in general, with concentration on electron microscopy; especially on scanning microscope, because research is taken just on the environmental scanning electron microscope. Another part informs about both general principles of dynamics of gases and with finite volume method. Another part deals with concrete used software and with setting of individual parameters for calculation. At the beginning of calculation are used five basic profiles of holes in diaphragms for pressure 1000 Pa in the chamber of the sample. For modelling individual shapes is used 3D parametric modeller SolidWorks. Analysis of circulation of secondary electrons through detector is made by using Cosmos FloWorks module. The most suitable type of diaphragms is chosen from measured models. Another part of diploma thesis deals with measuring of chosen types of diaphragms for more pressures in the chamber of the sample; the pressure is 200, 400, 600, 800 and 1000 Pa. The outcomes of this research are both models of pressure and speed of circulation inside the detector and graphically processed values by using different diaphragms, respectively one type of a diaphragm in different pressures. Production drawings of each diaphragm, together with calculated models, are enclosed.
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Design and adaptation of electron microscope accessories for in-situ experiments
Drozd, Michal ; Mikulík, Petr (referee) ; Kolíbal, Miroslav (advisor)
Účinnost katalyzátoru v kombinaci s optimalizovanou reakcí a minimalizováním jeho množsví jsou klíčovými faktory při snižování investičních a provozních nákladů v rámci chemických procesů. Díky pokročilým experimentálním technikám mohou být katalyzátory dále zlepšovány. Jednou z těchto technik je in-situ elektronová mikroskopie. Tato práce se zabývá vývojem zařízení pro automatický ohřev vzorku, automatickým vpouštěním reaktantů a měřením parciálních tlaků v komoře mikroskopu. Dále je pomocí provedených experimentů srovnán přístup pomocí environmentálního rastrovacího mikroskopu, kde se využívá laserový ohřev vzorku s přístupem, který využívá skenovací elektronový mikroskop připojený k ultra vakuové komoře, kde se vzorek zahřívá pomocí průchodu elektrického proudu.
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Classification of microstructure of nickel-base superalloys with image analysis using
Volf, Milan ; Čelko, Ladislav (referee) ; Němec, Karel (advisor)
During operational conditions of internal combustion turbines of turbojet engines, the impeller are stressed by load cycles which vary in time, temperature and stress. In the course of operation, the blades are exposed to a considerable number of degradation effects, particularly high-temperature corrosion, fatigue processes and creep. The presented work is aimed at the study of the structure cast nickel-base superalloy INCONEL 713 LC, creep tests exposured. The structural changes (degradation) was clasification by the help of image analyses. Operational conditions of heat parts, used in gas turbines and turbo-compressors, were simulated by creep tests of Inconel 713 LC nickel superalloy during a constant load of temperatures ranging from 750 up to 950°C. Changes in the structure dependent upon time, temperature and stress applied were analysed by means of light and electron microscopy methods and image analyses after the fracture of test bars.
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Specifications of the Ansys Fluent Solution Solver for low pressures in EREM
Šimík, Marcel ; Bílek, Michal (referee) ; Maxa, Jiří (advisor)
This thesis is focused on electron microscopy which issue is discussed at the beginning of work. The main attention is dedicated to the Environmental electron microscope, especially the differentially pumped chamber, which the thesis deals with. There is a production of an experimental chamber for analysis of shock waves on going therefore main goal of this thesis was to analyze the flow pattern in this chamber. Using the Ansys Fluent program, simulations of the characteristic flow that arises from the pumping of the vacuum chambers namely the ultrasonic flow at low pressures on which the most suitable turbulent module was applied as well as the degree of discretization was performed. The final analysis of this flow pattern is primarily focused on the localization of the shock wave which experimental evidence is to be lodged by shadow optical method as a part of the new concept of the chamber. The basis for the simulation of the chamber was taken over by Dr. Danilatos, with which the results were compared.
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