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Factors influencing the Character of Phase Transformations in the Fe - C System
Gubán, Ivan ; Němec, Karel (referee) ; Molliková, Eva (advisor)
The goal of this thesis is the study of the factors influencing the character of the phase transformation in the Fe-C system. Focusing on the speed of the cooling of alloys under the consideration and concentration of carbon in the alloy, which influences the form of carbon gelling in the alloys of iron and the resulting structure of the material. Because of the limited range, the thesis does not take into account the influences caused by the presence of the impure and alloying elements. The illustrations of the microstructure of the particular alloys or their schematic illustration. In conclusion, there is included transformation diagrams of the particular steel.
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Preparation of 2D heterostructures
Ředina, Dalibor ; Hrabovský, Miloš (referee) ; Bartoš, Miroslav (advisor)
This bachelor's thesis refers about preparation of 2D hetestructures here at the IPE, BUT. The first theoretical part deals with properties of graphene, molybdenum disulfide and 2D heterostructures in general. Comprehensive overview is provided by basic facts about properties and allotropic modifications of carbon. Next part of this thesis outlines methods used in the fabrication of heterostructures and highlights presumably the best one. Experimental part deals with optimization of this method. Successive steps of this method are improved by various adjustments in order to achieve the highest success rate in the fabrication of these heterostructures. Result of this approach is stated in this thesis.
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Carbon Fibre Composite Materials
Mikula, Martin ; Molliková, Eva (referee) ; Němec, Karel (advisor)
In the first part of a Bachelor's work there is a general introduction with composite materials. These materials are seperated on the basis of matrix kind. The production of composite materials is described as well. The second part is focused on the carbon fibre materials in more detail. The application of composite materials in aviation industry is in the third part of the Bachelor's work.
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Carbon Based Materials
Hrazdíra, Matěj ; Čelko, Ladislav (referee) ; Klakurková, Lenka (advisor)
The proposed bachelor thesis deals with carbon based materials. First of all, an overview of its allotropic modifications including newly discovered forms, conditions of their existence and also their basic properties is shown. Further the extraction of carbon materials is briefly introduced. In the next chapters, forms of carbon are classified and particularly described individually with respect to manufacturing technologies and further applications. Individual chapters are dedicated to synthetic carbon and graphite, carbon fibers and carbon fiber reinforced composites. Manufacturing processes of synthetic carbon and graphite, involving possible precursors, are described in detail together with their use in various engineering applications. The following part is dedicated to carbon fibers, in particular to the manufacturing process based on the precursor used including surface treatment and sizing. Additionally the use of virgin carbon fibers is also described. The last part is focused on carbon fiber reinforced composites. Firstly possible distributions of carbon fibers in a matrix are described. Then the technology of manufacturing, properties and use of single composites according to the matrix material are expounded.
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Model bilance uhlíku ("Carbon footprint") na malé a velké farmě
Johaníková, Alena
This thesis deals with load of carbon dioxide on large and small farm, which is subsequently converted by digestibility coefficients of nutrients to the equivalent carbon dioxide. The objects of the calculation are two given farms, located in the Zlín Region. Small farm entertain with 15 pieces of pig sows in a closed herd turnover and large farm breeding cattle herds with a turnover of 100 dairy cows. From the sales of the pig herds on a small farm, I found a total feed consumption, which is 133.5 tons per year, which I calculated the carbon content received from the compound feed, which is 50.35 tons and 3.08 tons of nitrogen per calendar year. Pigs in the feces excrete 8.12 tons of carbon and 0.52 tons of nitrogen. Pigs consume 0.36 tons of carbon and 0.44 tons of nitrogen per ton of edible particles in the meat. To produce 1 kg of meat consumes 0.246 kg of carbon. On a dairy farm income in total 1,645.29 tons of compound feed per year in which they adopt 609.61 tons of carbon and 31.23 tons of nitrogen. In feces they excrete 156.84 tons of carbon and 8.05 tons of nitrogen. In the milk is eliminated 42.78 tons 2.51 tons of carbon and nitrogen. The herd turnover of 31 bulls with the increments 1.4 kg / day 210.53 tons annually consume feed mixtures from which bulls take 71.70 tons, and 3.21 tons of carbon. In feces they excrete 18.09 tons and 1.10 tons of carbon and nitrogen in the meat, at the slaughterhouse is excluded 4.49 tons 0.35 tons of carbon and nitrogen. At the turn of the herd of bulls with the increments of 33.7 1.7 kg / day annually consumes 265.49 tons of feed mixtures from which the bulls take 71.70 tons and 3.21 tons of carbon nitrogen. In feces they excrete 21.35 tons and 1.35 tons of carbon and nitrogen in the meat, at the slaughterhouse is excluded 4.88 tons 0.38 tons of carbon and nitrogen. To produce 1 kg of meat bulls consume 0.248 kg of carbon. In conclusion are recommendations to reduce emissions at the farm which is needed.
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Why we identify term ?humus? with ?soil organic matter? in pedology, if it directs us to wrong deductios?
DVOŘÁK, Miroslav
To this day are terminological inaccuracies in subject publications, which direct us to wrong deductions. Therefore I devote oneself to literature search about soil organic matter, in my theses. Separately is split primary organic matter, levels of it´s lability and stable humus. I clarify the term stability and the difference in humus and primary soil organic matter. In this theses were effected analyses acid cambi soil in region Czech Budejovice and acid cambi soil in range of Bohemian Forest ? Kubova Huť. Was quantificated content HK, FK, Cox, humification degree SH, mineralized carbon Cminer, speed constant of biochemical oxidation C, fraction of labile organic substance Ccws, Chws, a CPM. I had compared this data with data, which we keep at one´s disposal from analyses effected twelve years ago. By comparing the real quality of humus in samples A (Kubova Huť) and B (České Budějovice) it stands to reason, that the B sample is superior in quality than sample A. Practice and media very often consider as ?humus? total content of Cox. If this thought should be the true, I would have to consider sample A (with content 9,3% Cox) as a soil with high level of humus and I would expect record returns in it. This conclusion would be real absurd. We can not talk about humus according to Cox content only. It is also necessary to take the primary claims (that the content Chws is an indicator of soil fertility) of some big men in field of pedology (for example Haynes) with a grain of salt. This applies only if soil micro ? edaphon is not decimated somehow. I came to the conclusions, that the final result of the analyses, effected by my thesis supervisor (Kolář) twelve years ago, on practically identical soil samples, are almost exactly the same with my results.
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Kinetics and temperature dependance of cellulose degrading enzymes in the Arctic soils
VAZAČ, Jan
Kinetics and temperature dependance of ?-glucosidase and cellobiosidase was investigated in Arctic soil. These enzymes are key in cellulose degradation, while ?-glucosidase produces the final product of cellulose degradation, the glucose, which si readily available to soil microbes and can influence the CO2 production. The enzymes activities was measured using fluorogenic substrates.
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Species palatability, life history traits and litter decomposition rate
PÁLKOVÁ, Kateřina
Palatability of 20 meadow plant species was assessed in the slug grazing experiment conducted. Monocots exhibited significantly lower palatability than dicots. Litter decomposition rate was assessed in the field litter-bag test. Linear regression analysis was performed to answer the main question whether species palatability is related to litter decomposition rate and whether it is determined by the carbon or nitrogen content. Phylogenetically independent contrasts were used to eliminate correlated phylogeny effect. Regression trees were used to detect the effect of species traits on species palatability and litter decomposition rate.
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