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Characterisation of alcoholic beverages by means of spectrospic methods
Fajtl, Zdeněk ; Omelka, Ladislav (referee) ; Polovka, Martin (advisor)
The bachelor’s project is focused on the problem of determination of thermo-oxidative stability of mixed Radler - type drinks with low alcohol content. The project consists of both, theoretical and practical parts. The theoretical part describes the basic technological procedures used in the production of lager-type beer and also mixed drinks of Radler type. It also deals with the issue of antioxidants and/or oxidative processes with specific focus on beer and its components. The author also pays attention to spectroscopic methods, which are recently extensively applied to characterize different qualitative and quantitative parameters of foods; predominantly UV-VIS, IR and EPR spectroscopy. These methods were chosen with respect to the topic being studied. In the experimental part, the application of EPR spectroscopy and spin traps methods for the characterization of thermo-oxidative stability of the selected group of commercially available samples of Radler-type beer is presented. The values of the induction periods which were taken as a measure of thermo-oxidative stability, are compared, both for the group of Radler-type beers under study and for the commercially available samples of typical lager-type beers of identical producers, which were taken as for reference.
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Processing stability of polyhydroxybutyrate (PHB)
Palkovský, Radim ; Figalla, Silvestr (referee) ; Tocháček, Jiří (advisor)
The aim of this thesis was to observe and to evaluate the effects of selected additives on stabilization of two poly-3-hydroxybutyrates - Biomer and Hydal. In the experimental section of the thesis,the physical properties of pure polymers, polymers with mixture of polylactid acid, boron nitride and Citroflex 4A as well as the samples with five different additives which were added to this mixture, were meassured. Whilst processing the samples, the torque inside of the kneader was recorded. Tensile strength, Young´s modulus and relative extension were evaluated using tensile tests. Next, the differential scanning calorimetry was used to determine the melting points and their changes in comparison to the pure polymers. To evaluate the thermooxidative stability, method of induction periods was used, where the amount of time needed for degradation to make the material brittle was observed and recorded. These methods determined the the Stabilizer 9000 (Raschig) as the most suitable, owing to its better thermooxidative stability and considerable relative extension. As for DHT-4A on the other hand, it was proven that within P3HB it supports degrading processes, which devaluate the processing properties of this material even more. Amongst the other additives no significant influence on the material was observed and the changes of properties were attributed to the mixture of PLA and the other substances.
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Properties comparison of two products used for skating rink based on ehtylene-propylene-dien rubber
Kostková, Jana ; Kučera, František (referee) ; Bálková, Radka (advisor)
This master thesis deals with characterization of two black and white products based on ethylene-propylene-diene rubber (EPDM) used for skating rink. Products marked with A and are different in their diameter of circular tubes trough which cooling medium passes and also in the distance of these tubes. Both of materials were characterized in order to determine whether it is the EPDM and how are they different. The characterization methods were used: differential scanning calorimetry, thermogravimetric analysis, attenuated total reflectance Fourier transform infrared spectroscopy, tensile test, swelling test, thermooxidative test. The composition of both materials, including fillers and others additives is almost the same but difference is in structure of EPDM and probably also in interaction with fillers, what exhibits different mechanical properties, thermooxidative stability and thermal capacity. These differences which have been found are essential for long-term use properties of both materials.
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Processing stability of polyhydroxybutyrate (PHB)
Palkovský, Radim ; Figalla, Silvestr (referee) ; Tocháček, Jiří (advisor)
The aim of this thesis was to observe and to evaluate the effects of selected additives on stabilization of two poly-3-hydroxybutyrates - Biomer and Hydal. In the experimental section of the thesis,the physical properties of pure polymers, polymers with mixture of polylactid acid, boron nitride and Citroflex 4A as well as the samples with five different additives which were added to this mixture, were meassured. Whilst processing the samples, the torque inside of the kneader was recorded. Tensile strength, Young´s modulus and relative extension were evaluated using tensile tests. Next, the differential scanning calorimetry was used to determine the melting points and their changes in comparison to the pure polymers. To evaluate the thermooxidative stability, method of induction periods was used, where the amount of time needed for degradation to make the material brittle was observed and recorded. These methods determined the the Stabilizer 9000 (Raschig) as the most suitable, owing to its better thermooxidative stability and considerable relative extension. As for DHT-4A on the other hand, it was proven that within P3HB it supports degrading processes, which devaluate the processing properties of this material even more. Amongst the other additives no significant influence on the material was observed and the changes of properties were attributed to the mixture of PLA and the other substances.
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Properties comparison of two products used for skating rink based on ehtylene-propylene-dien rubber
Kostková, Jana ; Kučera, František (referee) ; Bálková, Radka (advisor)
This master thesis deals with characterization of two black and white products based on ethylene-propylene-diene rubber (EPDM) used for skating rink. Products marked with A and are different in their diameter of circular tubes trough which cooling medium passes and also in the distance of these tubes. Both of materials were characterized in order to determine whether it is the EPDM and how are they different. The characterization methods were used: differential scanning calorimetry, thermogravimetric analysis, attenuated total reflectance Fourier transform infrared spectroscopy, tensile test, swelling test, thermooxidative test. The composition of both materials, including fillers and others additives is almost the same but difference is in structure of EPDM and probably also in interaction with fillers, what exhibits different mechanical properties, thermooxidative stability and thermal capacity. These differences which have been found are essential for long-term use properties of both materials.
|
|
|
Characterisation of alcoholic beverages by means of spectrospic methods
Fajtl, Zdeněk ; Omelka, Ladislav (referee) ; Polovka, Martin (advisor)
The bachelor’s project is focused on the problem of determination of thermo-oxidative stability of mixed Radler - type drinks with low alcohol content. The project consists of both, theoretical and practical parts. The theoretical part describes the basic technological procedures used in the production of lager-type beer and also mixed drinks of Radler type. It also deals with the issue of antioxidants and/or oxidative processes with specific focus on beer and its components. The author also pays attention to spectroscopic methods, which are recently extensively applied to characterize different qualitative and quantitative parameters of foods; predominantly UV-VIS, IR and EPR spectroscopy. These methods were chosen with respect to the topic being studied. In the experimental part, the application of EPR spectroscopy and spin traps methods for the characterization of thermo-oxidative stability of the selected group of commercially available samples of Radler-type beer is presented. The values of the induction periods which were taken as a measure of thermo-oxidative stability, are compared, both for the group of Radler-type beers under study and for the commercially available samples of typical lager-type beers of identical producers, which were taken as for reference.
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