National Repository of Grey Literature 130 records found  beginprevious121 - 130  jump to record: Search took 0.00 seconds. 
The optimization of phosphate binders compozition used for refractories
Kalousová, Hana ; Ptáček, Petr (referee) ; Opravil, Tomáš (advisor)
This thesis deals with optimization of the composition phosphate binders. These binders are used in production of refractories. In this branch, the bauxite is very often used as an aggregate, but it contains tiny particles of iron which arise in milling process. These particles of iron react with the phosphate binder to form hydrogen – it is consequence of the reaction between phosphoric acid and iron. The formed gas causes the formation of bubbles and the deformation of refractories. The goal of this thesis is to find suitable additives which can be used to stop or to limit the production of hydrogen. Usually used binders were replaced by a model binder to simplify the system and for better understanding. The model binder was prepared in laboratory by dissolving aluminium hydroxide in phosphoric acid. They used pure powdered pentacarbonyl iron instead of tiny iron particles from the milling process. The model binder was modified with using a few inhibitors. The calcimetr was used to measure their influence on the production of hydrogen, as well as measuring concentrated rows of selected inhibitors. These rows are necessary to optimize the inhibitors quantity added in the binder.
The formation of gehlenite and anortite in the ceramics body.
Matysová, Dorota ; Šoukal, František (referee) ; Ptáček, Petr (advisor)
This bachelor thesis deals with the study of mechanism and kinetics of gehlenite and anorthite formation in the ceramic body. Methods used for this study were thermal analysis (TG-DTA-EGA), HT-XRD and heating microscopy. The Kissinger equation which belongs to the mechanism-free isoconversional methods was used for the determination of the activation energy, the pre-exponential factor and the Avrami coefficient. Characteristic of reactants kaoline Sedlec Ia and precipitated CaCO3 (Penta, p.a.) using IR spectrometry, thermal analysis (TG-DTA-EGA), SEM and heating microscopy is also included in this thesis.
Modification of dry stuff with lime sludge
Švec, Jiří ; Kovářová, Alena (referee) ; Ptáček, Petr (advisor)
In modern point of view of waste management is desirable to effectively process the grates possible amount of wastes. Sediments from cleaning of mined lime stones contains a lot of clay components, but there is also indispensable share of soft calcite. Especially this can be use in following processing. After firing, where is necessary to set suitable temperature, arises a mixture of soft calcinated lime and remaining dehydrated mineral components. This calcinated mixture could partially replace used binders in dry stuffs.
Flow properties of hyaluronan colloids
Gabrielová, Michaela ; Ptáček, Petr (referee) ; Pekař, Miloslav (advisor)
The purpose of this study is to zoom in implication of flow properties of hyaluronan colloids with respect to physiological role. In the first part I will introduce physical formulation and definition of flow properties and reology, process to its measurement and utilization. In the second part you can read about hyaluronic acid and colloids of its salts. In this part I will focus on first studies of hyaluronic acid throught its occurence to its chemical properties. Within this work I will try to demonstrate interconnection of both subjects.
Gypsum free cements with retarded setting by plastisizer and alkali compond
Sedlařík, Tomáš ; Ptáček, Petr (referee) ; Havlica, Jaromír (advisor)
This thesis deals with preparation of gypsum free cements with retarded solidification. It focuses on their preparation by alkali activation with addition of superplasticizers and without superplasticizers. The main aim of this work is to suggest substitution of gypsum in Portland cement by other materials. Ash after fluidized combustion was chosen as a good compensatory raw material with respect to sustainable development. Milled fluidized bed ash from heating station Třinec was tested. Examined pastes were prepared by alkali activation. 50% solution NaOH and sodium water-glass were used as alkali activators. Trial specimens (20x20x100 mm) were prepared from pastes. Measurements of calorimetric properties of unprocessed pastes tested mixtures were implemented. Bending and compressive strength of pastes were also explored.
Preparation of light composites on the basis of alkali activated fly ashes from high temperature combustion of coal
Weiglová, Jana ; Ptáček, Petr (referee) ; Havlica, Jaromír (advisor)
This thesis studies possibilities of preparation light composite materials based on solid residues from high-temperature burning. The main focus is put on potential alkaline activation by water glass and 50% sodium hydroxide solution. Further on, the thesis analyzes suitable additions which when added into alkaline environment with alkali release gas and thus enable to create light porous composites. The aim of this work is to suggest one or several recipes for preparation of light composites made from solid residues from high-temperature burning through alkaline activation. To method of XRD diffraction analysis has been used to identify the products of hydration and alkaline-siliceous reaction (phases) of alkaline activation.
TiO2 pillared clay for photocatalytic purposes
Fiala, Michal ; Šoukal, František (referee) ; Ptáček, Petr (advisor)
Bachelor’s thesis describes preparation of mixed catalytic systems kaolin/ TiO2 and metakaolin/ TiO2. Samples were prepared via hydrolysis of TiCl4 in kaolin suspension. Catalyst metakaolin/ TiO2 was prepared by calcination of this material under static oven atmosphere at 600 °C. Thermal analysis (simultaneous TG-DTA), infrared spectroscopy (FT-IR) and electron microscopy (REM) were used for samples characterization. Catalytic efficiency of mixture kaolin (Sedlec Ia) or metakaolin with TiO2 (anatase) was compared with pure kaolin. Experiment is based on oxidation of ethylalcohol, which was introduced in to reactor in flow of inert gas (argon). Amount of decomposed ethylalcohol is proportion to concentration of oxygen in gas product outputting from reactor. System kaolin/ TiO2 show higher catalytic performance than metakaolin/ TiO2 catalyst.
Guerrilla marketing
Ptáček, Petr ; Bursíková, Marcela (advisor) ; Šír, Martin (referee)
Práce popisuje hlavní principy a myšlenky guerrilla marketingu, jeho různé styly a odnože a rozdíly oproti marketingu tradičnímu. Důraz je kladen na rozdílnost přístupu a stylu myšlení. Součástí jsou i aplikace jednotlivých myšlenek nebo nástrojů guerrilla marketingu na reálné nebo hypotetické situace, doplněné rozborem případových studií.
Application satellite navigation systems in transportation
Havlík, Martin ; Zelený, Lubomír (advisor) ; Ptáček, Petr (referee)
The work focuses on the application of satellite navigation systems in the different transport fields. It describes the general principle of operation of navigation systems, as well as its history and development. The following section describes the current navigation systems, the principle of operation, architecture and services. A separate chapter is devoted to being the European Galileo system and its services. Practical work deals with the applications according to the navigation systems across different transport sectors. In addition to the transport sector are given applications in other areas of human activity. The main part is devoted to the application in the monitoring and management of the company's fleet. Part of the analysis is the calculation of the efficiency of this investment.

National Repository of Grey Literature : 130 records found   beginprevious121 - 130  jump to record:
See also: similar author names
1 Ptáček, Patrik
12 Ptáček, Pavel
1 Ptáček, Petr Bc.
1 Ptáček, Přemysl
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