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Comparison of hydrolysis of selected phytomass after thermopressure preparation.
MAROUŠEK, Josef
Presented work compares the effect of mild extrusion on starchy and cellulose phytomass at different levels of intensity of acid (H2SO4, 3, 6, 9 and 12%), alkaline (NaOH, 3, 6, 9 and 12%) and enzymatic (4 enzyme preparations to hydrolysis of starch, 6 preparations for hydrolysis of cellulose and hemicellulose) hydrolysis. To measure the depth of hydrolysis is used GE and additionally alcohol yield. The positive impact of applied 0.3 MPa and 1MPa extrusion is also investigated by absorbance values and filter coefficients.
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Evaluation of dimensional and shape accuracy of components made of plastic
Tuza, Marek ; Dobrocký, David (referee) ; Sedlák, Josef (advisor)
The aim of this thesis is to evaluate the dimensional and shape accuracy of components made of plastic. A total of 10 samples, produced by two types of production, extrusion and 3D printing using the FFF method, were used for this purpose. The semi-finished products were milled after production, which resulted in samples of the required dimensions. The samples were milled on one side without cooling emulsion and on the other side with cooling emulsion, which significantly affected the resulting shape accuracy values. Thus, a total of 20 surfaces were evaluated. Two parameters were selected to evaluate the dimensions, namely distance and parallelism. When measuring the shapes, 11 parameters were evaluated using a 2D roughness profile and a 3D surface texture. One of the most used parameters that was evaluated when measuring shapes was the arithmetic mean deviation of the roughness profile, which is denoted as Ra. The research found that the highest accuracies were measured for the material PA produced by 3D printing and milled with a cooling emulsion. At the end of the practical part, the author also makes recommendations regarding the practical use of materials.
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Effective management of plastic waste
Kostková, Kateřina ; Pavlas, Martin (referee) ; Gregor, Jiří (advisor)
The main content of the submitted diploma thesis is the implementation of analysis of separated plastic waste and examination of the issue of extrusion tests. The practical knowledge is preceded by a search of waste management in the Czech Republic and get acquainted with the issue of polymer materials. The research is about plastic waste management and preparation of polymeric materials for extrusion tests. Theoretical knowledge is then applied in the practical implementation of extrusion tests.
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Experimental comparison of recycled and non-recycled filament of ABS plastic
Grygar, Filip ; Krčma, Martin (referee) ; Koutecký, Tomáš (advisor)
Plastic waste which arises from 3D print could be recycled. One of the most used materials is ABS with which this degree work deals. During recycling of ABS mechanical qualities rapidly deteriorate which is compensated by adding non-recycled ABS. This degree work dealt with a ratio of 25% of recycled to 75% of non-recycled material which is a ratio not have been tested so far, and most likely represents a boundary ratio when recycling still makes sense. Unfortunately, it was not possible to extrude from a recycled material a filament of high-quality enough which could be used for problem-free print. It was influenced by non-homogeneity of crushed components and the construction of an extruder. For improving the characteristics a more complex extruder would be needed, with a bigger screw diameter or with two screws, and also a cooling system with more zones. Professional grinders with screens would have to be used for improving homogeneity of the material. The melt flow index of the liquid alloy and the testing of the filament itself showed that this way is practicable and such a recycling is realistic.
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Experimental comparison of filament produced from recycled and regular PET
Tomčová, Renata ; Vaverka, Ondřej (referee) ; Koutecký, Tomáš (advisor)
This bachelor thesis deals with the experimental comparison of filament made from recycled and common PET. Filament was made from commercial granulate of PET, PET-G and from recycled PET bottles. Sample pieces were printed using FDM technology from these filaments and then the sample pieces were tested using a tensile test. The sample pieces made from recycled PET filament had one third worse tensile strength than the sample pieces made from common PET and PET-G filaments. Thanks to this bachelor thesis it is possible to decide, if it is worthy producing filament from recycled PET bottles even at the cost of reducing the mechanical properties of final products.
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Technologické úpravy krmiv
ŠENKYPL, Petr
This bachelor work describes methods of animal feed processing which represent an important step in animal feed. Emphasis is put on the description of feed processing technologies and their use in animal feed. Nowadays, thermal feed processing methods play a crucial role among feed processing methods. Thermal feed processing methods can significantly influence the economy of the farming practice and quality of the feed. Furthermore, the bachelor work describes the influence of the feed processing on the quality of feed, primarily on the content of nutritional and antinutritional factors, feed palatability and its suitability for particular groups of livestock.
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Extruze a její využití v cereální technologii
Tesař, Miroslav
The aim of study was describe the extrusion and its application in cereal technology. The study contains an overview of the normally used grains and other raw materials. There is also described the principle of extrusion technology applied to specific production conditions. With that is associated manufacturing equipment, extruders, whose parameters are also included in this work. The important part is the changes of raw materials during the extrusion process. The second part about cereal extruded products. The food market offers a wide range of extruded products. Individual products require specific manufacturing processes. This work includes a qualitative assessment of extruded products expanded of my practical own sensory evaluation extruded snacks.
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Influence of Solid Solution Elements and Precipitate Formation on the Mechanical Behaviour of Magnesium Alloys
Illková, Kseniya ; Chmelík, František (advisor) ; Karlík, Miroslav (referee) ; Landa, Michal (referee)
Title: Influence of Solid Solution Elements and Precipitate Formation on the Mechanical Behaviour of Magnesium Alloys Author: Mgr. Kseniya ILLKOVÁ Department / Institute: Department of Physics of Materials, Faculty of Mathematics and Physics, Charles University in Prague Supervisor of the doctoral thesis: Doc.RNDr.František Chmelík, CSc. Department of Physics of Materials, Faculty of Mathematics and Physics, Charles University in Prague Abstract: Mg-1 wt. % Mn alloys containing about 1 wt.% of calcium (MX10), aluminium (AM11), cerium(ME11), yttrium (MW11), neodymium (MN11) and 8 wt.% of aluminium (AM81) were indirectly extruded with two different speeds. The partially recrystallised microstructures obtained in MX10, AM11, ME11 and MW11 after slow extrusion exhibited bimodal grain size distributions. Only in the case of AM81 and MN11 a fully recrystallised microstructure was found, indicating differences in the grain nucleation rate during recrystallisation. In these alloys, the weakest texture and, correspondingly, the lowest asymmetry in mechanical properties were also observed. The acoustic emission technique was used to reveal dislocation or twin controlled deformation in differently textured fractions of the microstructure during tensile and compression testing. A direct correlation between the acoustic...
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Properties of polyethylene blown-films dependent on their composition
Štaffová, Martina ; Poláček, Petr (referee) ; Tocháček, Jiří (advisor)
This work deals with the influence of quantity of recycled material on physical properties of blown-film. The task of this work is to prepare set of laboratory made films with amount of LLDPE granulate from 0 to 100 % with addition of LDPE recycled material and furthermore with addition of filler, calcite. The following methods were used for characterization of blown films: tensile test, differential scanning calorimetry, Fourier transform infrared spectroscopy, confocal laser scanning microscopy. The same measurements were performed also on industrial made blown-film.
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Fatigue endurance of extruded Mg alloy AZ91E
Sobola, Petr ; Štěpánek, Roman (referee) ; Pantělejev, Libor (advisor)
This thesis deals with fatigue behaviour of magnesium alloy AZ91E produced by extrusion. In the frame of this work, basic mechanical characteristics and data from performed fatigue tests were obtained. Further metallographic analysis of microstructure and fractographic analysis of broken specimens after fatigue tests were carried out.
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