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Thermal analysis of fuels
Šrámek, Zbyněk ; Hrnčířová, Michaela (referee) ; Moskalík, Jiří (advisor)
The main goal of this thesis is to introduce the field of thermal analysis as an independent scientific discipline. The first section is mostly informative and introduces into a concept of thermal analysis. The second part describes the most fundamental and essential methods of thermal analysis and the last section is focused on evaluating a real thermogravimetric experiment which deals with biomass sample.
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Characterization of humic substances isolated from natural waste treated by vermicomposting process
Marková, Kamila ; Doskočil, Leoš (referee) ; Enev, Vojtěch (advisor)
This bachelor thesis deals with the study of humic substances isolated from vermicompost natural waste through spectrometric methods. The aim of this thesis is to study physicochemical properties of the humic substances through modern instrumental techniques such as molecular absorption spectroscopy in the ultraviolet and visible regions of electromagnetic radiation (UV/Vis), infrared spectroscopy with Fourier transformationn (FTIR), elemental analysis (EA), thermogravimetric analysis (TGA) and inductively coupled plasma emission (ICP OES). A research focused on basic information about the humic substances was developed in the theoretical part. A description about their distribution or structure was made and also their utilization in medicine, industry or ecology. Then, methods, which are used for study of the humic substances, were described as well. An essential part of the thesis was isolation of humic and fulvic acid from the vermicompost natural waste. Absorption coefficients were calculated from the measured UV/VIS spectrum which served to following characterization of HK and FK. FTIR spectrum was used to determination of functional groups of studied HL. An area of biogenic elements was specified using the elementary analysis. Total amount of studied trace elements was determined with with the help of ICP-OES.
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New materials for Li-ion batteries with conversion mechanism
Petr, Jakub ; Straková Fedorková, Andrea (referee) ; Sedlaříková, Marie (advisor)
This thesis is interested in new materials for lithium – ion batteries. Two different samples were investigated, one intercalation and one conversion cathode material. The theoretical part is focused to the structure of cells, their advantages and disadvantages compared to other secondary batteries. Also other materials used in batteries are described. The practical part describes the preparation of cathode materials for subsequent testing by scanning elektron microscopy and thermogravimetric analysis. In conclusions two different materials were evaluated and compared with each other.
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Correlation of Thermoanalytical Data with Primary Properties of Humified Substrata
Kislinger, Jiří ; Šimon, Peter (referee) ; Tesařová, Marta (referee) ; Schaumann, Gabriele (referee) ; Pekař, Miloslav (advisor)
Tato dizertační práce je napsána jako termoanalytická studie humifikovaných substrátů, tj. huminových látek a půdních vzorků, získaných z několika různých zdrojů tak, aby byl pokryt co nejširší rozsah primárních charakteristik. Práce hledá lineární korelace (s využitím Pearsonova korelačního koeficientu) mezi kinetikou termo-oxidační degradace (sledovanou pomocí termogravimetrie (TGA) a vyjádřenou konverzním časem stanoveným neizotermickou izokonverzní metodou) a standardními charakteristikami, jako je množství aromatického a karboxylového uhlíku přítomného v huminových látkách stanoveného spektroskopií nukleární magnetické rezonance (NMR). Hlavním cílem této práce je objasnit proces termo-oxidační degradace humifikované části přírodní organické hmoty a hledat závislosti mezi primární a sekundární strukturou huminových látek. Dalším úkolem je nalezení korelace mezi termogravimetrickým úbytkem hmotnosti půdních vzorků a jejich mikrobiální stabilitou měřenou v laboratorních experimentech jakožto půdní respirace (tedy uvolňování oxidu uhličitého). Účelem je zjistit, zdali vzájemné propojení vůbec existuje, a objasnit jaké druhy procesů, které provázejí půdní respiraci, je možné jednoduše odhalit pomocí TGA. Výsledky práce skýtají detailnější pohled na termickou analýzu půdních vzorků a jiných humifikovaných materiálů. Hlavním přínosem této práce je prezentace vyskytujících se aplikací termické analýzy pro charakterizaci půdní organické hmoty a dále také příspěvek k rozvoji aplikací technik termické analýzy v půdní vědě.
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CHARACTERIZATION OF WRAPPAGING FILMS BASED ON POLYETHYLENE AND POLYPROPYLENE
Bělašková, Marie ; Poláček, Petr (referee) ; Bálková, Radka (advisor)
By seven kinds of coextruded and blown packing polyethylene and polypropylene based films, which are supplied by Granitol were characterized in this bachelor thesis. The following methods were used for characterization: thermogravimetric analysis, differential scanning calorimetry, Fourier transform infrared spectroscopy, confocal laser scanning microscopy , and scanning electron microscopy. The methods made possible to determine the composition of the films and to evaluate the degree of crystallinity.
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Application of thermal analysis in energetics
Skala, Šimon ; Šnajdárek, Ladislav (referee) ; Moskalík, Jiří (advisor)
This bachelor´s thesis deals with the thermal analysis. The first part contains general information about thermal analysis. The second part provides overview basic types of thermal analysis methods. In the third part there are described in detail two main thermal analysis methods. The last section is focused on realization and evaluation of thermogravimetric analysis of sample of a brown coal.
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Polyhydroxybutyrate modification by grafting of functional groups
Melčová, Veronika ; Tocháček, Jiří (referee) ; Přikryl, Radek (advisor)
Presented bachelor thesis deals with a characterization of the effect of chemical grafting on thermal and mechanical properties of poly(3-hydroxybutyrate). Two grafting methods were chosen, chlorination and fluorination of PHB. The aim of the theoretical part of the work was to create a complete literature review containing basic information about polyhydroxybutyrate and the latest scientific evidence about possibilities of chemical modification of this polymer. The experimental part describes the chemical treatment of the material itself, as well as preparation of samples for testing and performing the selected analysis. Chemically grafted polymers were subjected to thermogravimetric analysis to determine their thermal stability. Thermal behavior of materials was studied by differential scanning calorimetry. Also non-isothermal crystallization of samples was observed in order to evaluate the influence of the grafted halogen atom onto the nucleation activity of the polymer. Selected samples were also subjected to dynamic mechanical analysis and tensile test.
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Issues of stopping the hydration of alkali-activated slag using organic substances
Chadima, Jan ; Novotný, Radoslav (referee) ; Bílek, Vlastimil (advisor)
This thesis deals with the stopping of hydration of alkali activated slag by organic solvents and investigates to what extent the selected organic solvent affects the results of the analyses. The solvents used were acetone, diethyl ether, ethanol, isopropanol and methanol, and this is because these are the most commonly used organic solvents in practice. Thermogravimetric analysis along with differential thermal analysis was used to assess the degree of influence of organic solvents on the alkali activated slag and Portland cement samples. Methanol and acetone affected the samples the most and the longer the sample was stored in the solvent, the more it reacted with the organic solvent. The adverse interaction of organic solvent was greatest for the Portland cement samples. Samples that were rinsed with diethyl ether prior to analysis had lower mass losses than samples that were not rinsed. In the case of alkali activated slag, it was found that the way in which the thermogravimetric results were affected by organic solvents was highly dependent on the activator used, with the smallest effect observed for Na2CO3 activation, while the largest effect was observed for NaOH activation at temperatures below 600 °C, and for higher temperatures for water glass activation.
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Utilization of physico-chemical and spectroscopical methods in study on microbial extremofiles
Dobešová, Kateřina ; Enev, Vojtěch (referee) ; Sedláček, Petr (advisor)
The aim of this bachelor thesis is the determination od polyhydroxyalkanoates in the cells of extremophille bacterie, preformed by several methods. The chosen bacterium was Schlegelella thermodepolymerans DSM 15 344 Thermogravimetric analysis, infrared spectroscopy with Fourier transformation, and Raman spectroscopy were used in this thesis. The TGA method was used for the determination of extracellular and intracellular water in samples. The FTIR method was used in order to observe the amount od PHA, but aslo to observe the physical properties of the polymer in the sample, specifically to determine either amorphous or crystalline featuers of this polymer. Raman spectroscopy was used in oder to confirm the presence of PHA in the samples. All results e´were compared eith the results accomplished by gas chromatografy.
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Influence of the Application of Lignite on the Distribution of Organic Carbon in Soil
Širůček, David ; Záhora, Jaroslav (referee) ; Kalina, Michal (advisor)
This diploma thesis is focused on optimization of sequential chemical fractionation method to humeomics in order to be useful for determination of organic matter content and distribution and also organic elements in soil. Subsequently, the optimized method is used to assess the efect of lignite application as soil support on these soil characteristics. For these purposes, there were three source matrices of organic matter (lignite, soil and annual soil extraction after lignite application) fractionated by sequential chemical analysis. In parallel, these samples were also fractionated by classic alkaline extraction to obtain the so-called extractable fraction of organic matter (NOM). Individual fractions from sequential chemical fractionation as well as NOM samples were characterized by methods of elemental analysis (determination of organic elements), thermogravimetry (contents of ash, organic matter and moisture) and FTIR spektrometry (structural analysis). The results obtained from a large range of data from all humeomics fractions and NOM fractions showed that the method of sequential chemical fractionation gives higher yields of organic matter compared to classic alkaline extraction. Another indisputable advantage is the fact that the obtained fractions divided according to solubility and strenght of binding to soil inorganics can be better characterized by physical-chemical methods, which provides more detailed information about soil organic matter. The results of the work also show that in order for lignite as a support substance to significantly affect soil properties, a longer time, multiple sampling and repetition of individual fractionations would be needed.
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