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Application of different fractionation techniques for structure determination of ICP
Dostálová, Dagmar ; Kratochvíla,, Jan (referee) ; Buráň,, Zdeněk (advisor)
Impact E/P copolymer (ICP) is produced using gas-phase polymerization catalysed by Ziegler-Natta catalysts. This material with its excellent mechanical properties is used in many industries, for example in automotive industry to produce bumpers or instrument panels. Its properties depend on chemical structure which was analysed using DSC, 13C NMR and GPC. It was used 6 different samples of ICP for studies, the chosen samples have different ratio between ethylene and propylene in their copolymer phase. The samples were fractionated using preparative TREF and solvent extraction to obtain fractions, which composition depends on elution temperature. Obtained fractions and original samples were subsequently analysed using above-mentioned methods.
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Fractionation of humic acids isolated from lignite
Moťka, Pavel ; Barančíková, Gabriela (referee) ; Klučáková, Martina (advisor)
The diploma thesis deals with lignitic humic acids. Bibliographic search can be divided into three parts. The aim of the first part is characterization of humic substances, presence, composition, structure and exploitation especially of humic acids. The second part describes a division of heterogeneous mixture of humic acids into closed fractions with more specific properties. The final part is a study of solubility of humic acids. The experimental part of the diploma thesis is structured similarly. In this work, a gradual fractionation with pH is used. Obtained fractions were characterized by UV/VIS and FT-IR spectroscopy. We assessed the portion of ash and carboxyl groups have been identified. Subsequently, all fractions extracted by gradual fractionation as well as some soluble fractions obtained by direct fractionation have been analyzed in view of solubility and their behaviour in water environment. Both used methods were compared.
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Influence of E/P copolymer composition on impact copolymer properties
Dostálová, Dagmar ; Kučera, František (referee) ; Buráň, Zdeněk (advisor)
Houževnatý E/P kopolymer se vyrábí polymerací v plynné fázi, která je katalyzovaná Ziegler–Nattovými katalyzátory. Tento materiál s výbornými mechanickými vlastnostmi je používán v mnoha průmyslových odvětvích, např. v automobilovém průmyslu na výrobu nárazníků aut a palubních desek. Jeho vlastnosti závisí na chemické struktuře, která byla zkoumána pomocí metod DSC, SSA, 13C NMR, ATREF a FTIR. Výsledky analýz byly porovnány s mechanickými vlastnostmi vzorků - modulem pružnosti v ohybu a nízkoteplotní vrubovou houževnatostí dle Charpyho. Pro studium vlivu složení na mechanické vlastnosti bylo použito 5 různých vybraných vzorků houževnatého kopolymeru E/P s různým poměrem ethylenu a propylenu v kopolymerní fázi, které byly frakcionovány pomocí o-xylenové extrakce za účelem rozdělení materiálu na krystalickou část, složenou z krystalického E/P kopolymeru a PP, a amorfní část, tvořenou E/P kaučukem. Získané frakce i původní vzorky byly následně analyzovány výše uvedenými metodami.
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Speciation and fractionation analysis of metals in agricultural soils
Lepař, Petr ; Mládková, Zuzana (referee) ; Diviš, Pavel (advisor)
This bachelor thesis deals with the procedures and analytical techniques associated with speciation analysis and fractionation of metals in agricultural soils. The first part defines the basic concepts related to speciation, fractionation, soils and elements contained within it. The following chapters describe procedures of samples withdrawal and its adjustment including a description of some methods used for the purpose of extraction, fractionation and speciation analysis. The last chapter is devoted to listing of some separation techniques and instrumental methods used for the purposes of speciation and fractionation.
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Determination of eutrophication potential of particles in rivers and waterbody sediments
JAN, Jiří
Extraction solutions were assessed to find the most appropriate method for characterisation of particles in the context of release or uptake phosphorus in non-calcareous regions. Advantages and limitations of methods for determination of different phosphorus (P) forms and its important binding components iron and aluminium (hydr)oxides, were pointed out. Characterisations of these forms, that show highly different behaviour under changing environmental conditions, were used for the assessment of particles saturation with respect to P. Sorption/desorption behaviour of soil particles susceptible to erosion and their content of plant available P was tested. Strong correlation, which is dependent on P saturation ratio, was used to propose a method for the determination of soil erosion impact to supply dissolved P in stream waters of variable dissolved P concentration.
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What can we say about sediments, evaluation of reservoir sediments and their link to eutrophication
Jan, Jiří ; Borovec, Jakub ; Hubáček, Tomáš
This work is focused on a detailed sediment evaluation and potential sediment impact on the eutrophication of reservoirs. Two methods for this purpose are presented: i) fractionation for sediment particles characterization and ii) an application of gel minipeepers (DET probes) for sediment pore water sampling. By combining these methods we are able to determine the potential of P release from selected sediment. Examples of using/nthis approach on various sediment types are given to highlight the importance of determining not only the concentrations of total P in the sediment, but also, especially, the following: i) P concentrations in different forms, ii) concentrations of main binding partners for P in noncalcareous sediments – Fe and Al (hydr)oxides, iii) concentrations of dissolved P and Fe in sediment pore water, iv) concentrations of ions influencing redox/nconditions (NO3-) both in the water above the sediment and especially in the sediment pore water.
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Effect of spruce swamp forest drainage and restoration on soil organic matter quality
MASTNÝ, Jiří
The aim of the study was to determine the effect of spruce swamp forest drainage and water regime restoration on soil organic matter (SOM) quality. Six localities of spruce swamp forests in Šumava Mountains were studied (2 drained, 2 restored and 2 pristine). SOM quality was affected by long-term drainage. Spruce swamp forest restoration (3-7 years) did not have significant effect on SOM quality although other parameters (pH, bulk density, water level, plant coverage) changed.
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