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Way of assign of stereoregularity of polypropylene
Hoza, Adam ; Tocháček, Jiří (referee) ; Kratochvíla, Jan (advisor)
The purpose of this work is to evaluate and compare isotactic index value determination of polypropylene homopolymer using extraction and solubility methods. A series of nine PP samples in a powder form specified by molecular weights in the range from 29 to 154 kg/mol was investigated. The methods afforded separation of polypropylene into two portions, the soluble fraction, and the insoluble one. Extractions were carried out in a modified Kumagawa extractor. Polypropylene extracts were obtained using several organic solvents (pentane, hexane, heptane, and octane) at their boiling points. Soluble fractions were obtained by dissolving the PP sample in high boiling point solvents (xylene, decahydronaphthalene, and 1,2,3,4-tetrahydronaphthalene) and cooling the polymer solution to 23°C. All the fractions were characterized using 13C-NMR, SEC, and DSC methods. Comparison of the extraction and solubility methods showed significant differences in the amount, stereochemical structure, molecular weight, and crystallinity of soluble, and insoluble fractions.
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Keyword Extraction from Scientific Articles
Kyjovský, Marek ; Schmidt, Marek (referee) ; Smrž, Pavel (advisor)
The main goal of this thesis is to explore basic methods which is using for extraction of important words from articles. After that try to understand character of using keywords from the available set of testing English articles. Based on these findings, try to design and to implement a system which is using this methods. Then created system testing on the real English articles and after that try to analyse results.
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Multiresidual methods for the determination of pesticides in waters
Matušková, Monika ; Kubíčková, Kristýna (referee) ; Vávrová, Milada (advisor)
This bachelor´s work of theoretical character deals with multiresidual determination of pesticides in water. It is especially focused on pesticides generating residues in surface water, which - due to their toxicity and persistence in environment - require goal-directed monitoring. The division of pesticides is stated, and their properties, toxicity and elimination process are described in the work. Furthermore, possibilities of analytical determination, especially the methods of gas and liquid chromatography are introduced here. In the last chapter, the complete analytic procedure for determination of organochlorine pesticides is described.
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Main Text Extraction from Web Documents
Mrózek, Daniel ; Burget, Radek (referee) ; Bartík, Vladimír (advisor)
This thesis deals with the main text extraction from the web documents in HTML format. It describes some methods that are already used and their separation. The goal of the practical part is to propose an algorithm for main text detection in HTML pages using primarily text features in combination with position features. Block classification is solved by multilayer perceptron. It also describes implementation of the proposed algorithm, the testing procedure and presentation of the obtained results.
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Acoustic signal classification
Pospíšil, Aleš ; Balík, Miroslav (referee) ; Atassi, Hicham (advisor)
Bachelor's thesis is focused on automatic music genre classication. First part of work evaluates present situation and refer to published studies. Gained knowledge from there is applied in this work. In terms of nding solution for problem the work summarize and describe suitable music features and classication techniques like neural networks and k-nearest neighbor. Four selected classication classes were classical, electro, jazz and rock music. Result of work is user-friendly system that provides automatic music genre recognition. Achieved classication performance is more less comparable to human music genres recognition.
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Preparation of hydrogels with the addition of grape pomace extract
Mojžíšek, Jan ; Veselá, Mária (referee) ; Kovalčík, Adriána (advisor)
The scope of this bachelor thesis is the preparation of hydrogels with antioxidant properties. These properties are achieved by the addition of grape pomace extract. The theoretical part of the thesis briefly summarizes the basic characteristics of the gels and describes the basic quantities in rheology. Furthermore, the classification, preparation and use of hydrogels are described. Attention is paid in particular to gels falling into the category of edible hydrogels. Information on antioxidants and matolins is also given. In the experimental part, extracts from grape pomace are characterized in terms of carbohydrate content, phenolic compounds and antioxidant properties. The extraction itself was carried out in different concentrated aqueous ethanol solutions. The extract with the highest total antioxidant activity, as determined by the ABTS method, was used for the preparation of the hydrogels. Agarose is used for the preparation of hydrogels. The change in the rheological properties of the hydrogels due to the addition of the prepared extracts was observed. The specific structures in the hydrogels were determined by FTIR.
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Influence of the temperature on the preparing of asphalt mixtures with higher amount of RAP
Škrobáček, Petr ; Koudelka, Tomáš (referee) ; Varaus, Michal (advisor)
This bachelor thesis is focused on the preparation of the reclaimed asphalt pavement for production of asphalt mixtures. In the thesis there is investigated the effect of the temperature of preparation the reclaimed asphalt pavement on the characteristic of the bitumen content. In the theoretical part there is described bitumen as such and reclaimed asphalt pavement. In the practical part there is described the preparation of the material for laboratory tests. The next step is the extraction and distillation of bitumen. These bitumens are tested according to depredescribed tests: ‘Determination of needle penetration (ČSN EN 1426)’, ‘The softening point (ČSN EN 1427)’ and ‘Dynamic shear rheometer’. In the last section of this bachelor thesis there is a comparison of the individual properties of the rendered bitumen of the asphalt mixtures of reclaimed asphalt pavement, with the aim of evaluating temperatures of preheating and degradation of the bitumen on the final characteristic of the asphalt mixtures witch higher quantity reclaimed asphalt pavement. The measured values of the temperature for preparation of reclaimed asphalt pavement shows that the temperature of the asphalt mixture before production has a significant effect on the characteristics of the bitumen, which is included in the reclaimed asphalt pavement. There is evident the difference between specimen of the asphalt mixture of reclaimed asphalt pavement and the reclaimed asphalt pavement. It is visible only from the bottom layer too.
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Extraction Detoxification of Sensitive Components
Andrle, Marek ; Vávrová, Milada (referee) ; Mika, Otakar Jiří (referee) ; Skoumal, Miroslav (referee) ; Čáslavský, Josef (advisor)
Solvent extraction is one of the methods available for the decontamination of sensitive equipments that are contaminated with chemical warfare agents. The efficiency of extraction method have been verified on the samples, (steel or rubber) that have been contaminated with drops of mustard gas. These samples have been inserted into the extraction flow cell through which solvent (ethoxynonafluorobutane - HFE-7200) flowed. The solvent was sampled in the time intervals. These samples of solvent were analysed for the concentration of mustard gas. Process of extraction was monitored for the three operational factors (the solvent flow rate, temperature and the ultrasound power) and for three different situations (dissolution of drops of mustard gas, mustard gas desorption from the structure of the sample and dissolve drops of mustard gas with the subsequent desorption from the sample). The development of the decontamination process in time was found to consist of two stages. In the first stage the rapid dissolution of the liquid part of mustard gas in a solvent and in the second phase was such as mustard desorption from the structure of the sample and this phase was considerably slower. Extraction is to accelerate increasing the value of the flow of the solvent, the temperature and the performance of the ultrasound. These operational fac-tors have a significant impact on the thickness of the laminar layer of solvent, the solvent replacement coefficient in a cell, diffusion parameters in the process, the viscosity, the solubility of mustard gas in a solvent and the maximum achievable concentration of mustard gas in the rubber sample. The values of adjustable parameters was obtained by mathematical analysis of mathematical model. The progress of extraction under different operational conditions can be predicted by these parameters. The effect of solvents and ultrasound was experimentally verified for selected equipments of computing and communication technology. The possibility of separation of chemical warfare agents from the solvent was verified too.
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Determination of organic tin compounds in the environment
Fojt, Jakub ; Mravcová, Ludmila (referee) ; Řezáčová, Veronika (advisor)
Organotin compounds are one of the most produced and most used organometallic compounds. Some of these substances are endocrine disruptors, persistent organic polutants and their high toxic effects are observed. That’s why their presence in the environment caused by human activity could endanger many organisms. The aim of this thesis is summarize their properties and their occurrence in the environment. Then the quick, easy and relatively cheap method for determination of trialkyltin compounds in heavily poluted aquatic sediments using capillary zone electrophoresis is developed.
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