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Studium a vývoj polymer-cementových kompozitů s důrazem na vysoký obsah druhotných surovin a kompenzaci objemových změn
Hermann, Radek ; Bydžovský, Jiří (referee) ; Reitermann, Pavel (referee) ; Kolísko, Jiří (referee) ; Drochytka, Rostislav (advisor)
Reducing of humanity's carbon footprint is currently one of the main directions of global research. Another significant problem is the disposal, recycling and secondary use of waste materials produced from a wide range of industries and municipal waste. This thesis deals with the problematics of polymer-cement composites, which are most often used for rehabilitation, reprofiling and structural repairs, especially of concrete structures. The thesis examines and verifies the possibilities of utilization of a large amount of secondary raw materials and waste as a substitute for cement as a primary binder. At the same time, the work deals with the full replacement of the primary filler with waste raw materials, for which there is currently no other use. The work also addresses and verifies the influence of several commonly available commercial polymer dispersions. The work deals with the use of liquid, but also powdered polymeric additives of various bases. The work also deals with the problematics of volume changes of the hydration process of polymer-cement composites and the effect of volume changes on the physical-mechanical properties of composites. The influence of volume changes that occur during the hydration of polymer-cement composites is a significant criterion in the selection and use of these composites. The volume changes of the material have a great influence especially on the maximum layer thickness and the maximum area that can be repaired with the material without the risk of cracks and the need to create a working joint. The results of this work are associated with a reduction in the economic and environmental impacts of production and use of polymer-cement building materials and increase the usability of these materials mainly due to the possibility of remediation of larger areas than previously possible.
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Taboo and noa in communication. Realization of linguistic taboos in the print media
Junková, Anna ; Chejnová, Pavla (advisor) ; Janovec, Ladislav (referee)
Taboo and noa in communication. Realization of linguistic taboos in the print media. This thesis deals with issues of the taboo and noa in language and communication. The core of this thesis is to identify the essential tabooed themes in contemporary society and ways of their linguistic realization in the print media. In the theoretical part of this thesis is the first explained substance of the terms such as taboo, noa, communication and linguistic taboos with regard to the interrelations between these terms. In the empirical part are then defined tabooed themes occurring in the concrete texts of the diary Mladá fronta DNES and Blesk and of the periodical Rytmus života and ways of their linguistic grasping. The thesis focuses above all on the manifestations of speech restrictions in the lexical plan of the language.
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Synthesis of new guaiazulene derivatives
Počtová, Žofie ; Kotora, Martin (advisor) ; Smrček, Stanislav (referee)
Synthesis of new guaiazulene derivates (abstract) This bachelor thesis concerns preparation of new guaiazulene derivates. The purpose of this work was to try some already known reactions and some new ones. Acylation of guaiazulene was carried out and was followed by oxidation, decarboxylation, allylation, and Diels-Alder reaction of the prepared guaiazulene derivates. The desired products were obtained in acylation, oxidation, and allylation reactions. Characterization of the prepared substances was performed by using NMR, IR or MS techniques.
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Pupils' problems when solving problems requiring substitution
Schánělec, Jan ; Vondrová, Naďa (advisor) ; Novotná, Jarmila (referee)
Title: Pupils' problems when solving problems requiring substitution Abstract: The work focuses on 8th and 9th graders' difficulties and mistakes when solving problems using substitution. The theoretical part defines the used concepts and discusses selected results from international comparative studies and studies focusing on substitution. The main goal of the work is to identify pupils' difficulties and mistakes they make when solving problems using substitution and to discover their origin or cause. To achieve this goal the empirical part begins with an analysis of three sets of textbooks used by pupils involved in this research study. This is followed by a description of conducting and subsequent analysis of fifteen clinical interviews on problems with substitution with 14 to 15 year old pupils (9th graders from elementary schools and 3rd graders from lower secondary grammar schools). In the final part the most common mistakes are summarised and relations to their possible origin in the set of textbooks used looked for. The conclusion is that pupils do not have problems with substitution as such when substituting natural numbers into first power variables. However, this does not hold for substitution of variable in the second power. Pupils have problems when substituting for a variable with a negative...
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Exploring the Interaction between Foreign Direct Investment and International trade with a Focus on CEECs.
Zhang, Ling ; Szobi, Pavel (advisor) ; Figueira, Filipa (referee) ; Jeřábek, Petr (referee)
Our research reveals the impact of foreign direct investment on the intensity of bilateral trade in the Central Eastern European (CEE) region, focusing on countries of Czech Republic, Hungary, Poland, Slovakia, Slovenia, and Estonia (CEE-6). Previous literature and research results indicate that there is a complementary or substitute relationship between FDI and trade. However, the studies of this subject on the CEE region are scarce. Our study employs the gravity model to analyze the impact of FDI on bilateral trade with panel data of each country from 2005 to 2019. Based on the panel data, we investigate the commercial integration among CEE-6 and with main EU commercial partners. Our results suggest a prevalence of complementary relationships in Hungary, Poland, Slovakia, and Slovenia, yet each country demonstrates the relationship through different facts. The complementary relationship is attributed to the prevalent vertical FDI in CEECs, especially in the automotive industry. However, Estonia displays a substitutive relationship between outward FDI and trade. Moreover, we find the commercial integration only exists among the Visegrad group.
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Vliv substitucí na magnetokalorický jev u vybraných sloučenin vzácných zemin
Kaštil, Jiří
The anisotropy of the magnetocaloric effect was studied on DyNiAl single crystal. Our data reveal a strong anisotropy of the magnetocaloric effect. The large effect occurs for field applied along the c-axis whereas the entropy change is small for the perpendicular field direction. The influence of substitution on the magnetocaloric effect was measured in the Gd(Co1-xRhx)2 compounds (where x was from 0.05 to 0.30) and Dy(Co1-xFex)2 compounds (where x was from 0.00 to 0.03). The substitution of Co by Rh leads to a decrease of the transition temperature, Tc, and increase of the maximum entropy change. The Tc increases but the maximum of entropy change quickly decreases in case of Fe substitution. The last studied systems were the Gd1-xTbx alloys with x in range from 0.00 to 0.40. The influence of the sample shape and orientation was studied. The thin ribbon oriented along the magnetic filed gave the highest value of the entropy change. The three measurement techniques were used: the heat capacity measurement, the magnetization measurement and the direct measurement of the temperature change.
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Development of new grouting materials for reverse grouting of sewers
Dolák, Martin ; Dohnálek,, Pavel (referee) ; Drochytka, Rostislav (advisor)
ABSTRACT This thesis deals with the development of silicate based reverse grouts for the purpose of rehabilitation of sewers. The work also examines the possibility of substitution of basic input raw materials with secondary raw materials, meaning replacements of both filler components and binder components. As secondary raw materials, we refer to wastes from the production process which, after the necessary treatment, are used in another production. The development and experimental verification of the functionality of the developed grout was focused mainly on the use of secondary raw materials as much as possible, while maintaining or even improving its physical and mechanical properties. Based on the results of the work, it can be stated that with a 100% replacement rate of filler components in combination with 20% replacement rate of binder components, it is possible to largely maintain the properties of the material, or even optimize them. The results of the thesis also point to the possibility of reducing the economic and environmental demands of production of building materials.
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Electrically conductive composites based on secondary raw materials
Baránek, Šimon ; Šteffan,, Pavel (referee) ; Černý, Vít (advisor)
Electroconductive composites are modern materials that are commonly used in many industries such as the construction industry among others. For example these materials can be useful as sensors for monitoring changes in constructions. The aim of this thesis is the research of electrically conductive silicate composite based on secondary raw materials. The design of this composite is based on the development of its own mixtures and experimental verification of the effect of the structure. The introduction part consists of a detailed analysis of 15 materials. Samples of the 5 fine and 2 coarse electrically conductive fillers were tested. Composite with filler Condufit C4 was selected as representative for type of fine fillers. Composite with filler Supragraphite C300 was selected as representative for type of coarse fillers. The selection of the composites was based on the impedance of the fabricated composites with these fillers. Subsequently, the individual components of the primary mixture were substituted. The cement was replaced by high-temperature fly ash in the amount of 20, 30, and 40 %, the aggregate of a similar fraction was replaced by steel sawdust, and the primary electrically conductive fillers were replaced by secondary ones in the amount of 30 and 50 %. All proposed replacements reduced the impedance of the composite. The most effective replacement for impedance reduction was replacement with waste graphite (up to 92 % reduction), which also slightly improved the mechanical properties of the composite. The result of this thesis is an optimized electrically conductive composite based on secondary raw materials with a fine type of filler with 30 % replacement by waste graphite "odpad vysavač"which achieves an impedance of 5 ohms. The partial goal of this thesis is a verification of the influence of moisture on the impedance of composites. Results are significantly affected by moisture when using the coarse type of filler, when using the fine type are not.
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Obchodovanie s palmovým olejom v potravinárstve ČR
Kropiľáková, Katarína
The bachelor thesis is focused on the level of palm trading in the food industry of the Czech republic. At the same time, it deals with palm oil utilization in the manufacturing process of companies that use palm oil as one of their main inputs for their products. Another intention was find out which companies in Czech republic did not use palm oil in their production and how they replace it. A proportion of bachelor thesis is also focused on the question of substitution. The aim was to find out why palm oil is irreplaceable for the majority of food companies and vice versa, for what reasons are some companies strictly for non-use it.
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