National Repository of Grey Literature 128 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
The Suggestion of Optimal Supply Process for New Orders
Adamík, Vít ; Sedláček, Petr (referee) ; Jurová, Marie (advisor)
The topic of diploma thesis was implemented in selected mechanical engineering company producing precision parts in small series. The main aim of the thesis is to create the suggestion of optimal supply process for new orders. The first part of thesis describes the company, area of its business and the processes of the order. In second part, the production analysis is carried out: production order path, production analysis for two reference parts, comparison of all time delay over two last years, find bottlenecks in the supply process. Base on analysis, theoretical approaches was described. In the last chapter there are suggestions for improvement of supply processes and thus shortening of production time of new orders.
Study on adhesion properties of hydrogels to solid surfaces
Šindelářová, Anna ; Sedláček, Petr (referee) ; Smilek, Jiří (advisor)
This bachelors thesis deals with optimization and subsequent verification of the applicability of an unconventional method for determination of adhesion properties of hydrogels and materials related to them, which will then be useful for measuring the adhesion of hydrogels to solid surfaces using rheological techniques. In the case of the presented thesis, the determination of adhesion properties by means of rheometer and simple experiments such as slipping of measured materials on inclined surface is chosen. The results of both of these methods are compared to each other and also to the knowledge gained from literature. The applicability of the methods is assessed in terms of objective results, reproducibility, and whether the measured data are quantitative expressions of adhesion properties. It has been found that rheometry is useful as a reliable quantitative method of measuring adhesion. The rheometric data was reproducible and consistent. By this method, it was found that, with increasing concentration of dispersion, the adhesion force increases, which is in agreement with the knowledge obtained from literature.
Influence of particle size on microreology experiments using fluorescence correlation spectroscopy
Pavlíková, Stela ; Sedláček, Petr (referee) ; Mravec, Filip (advisor)
This diploma thesis deals with microrheology measured via the fluorescence correlation spectroscopy. As microrheological probes, fluorescently marked nanoparticles of 5 sizes in the range of 10-100 nm, were used. The particles had been immersed in a variety of concentrated glycerol solutions and agarose gels of different concentrations, and the FCS measurement revealed a diffusion coefficient of individual particles in each environment. Based on the coefficient, the viscosity of the glycerol needed to stop the particles could be determined. Particles of 10 nm size were not stopped even by the 100 wt% glycerol. In the case of the agarose gels, a combination of higher agarose concentration and larger particles resulted in an increase in the diffusion coefficient to an unlikely high value. This was caused probably by an agarose autofluorescence and the value indicates stopping of the particles in the given agarose gel. Later, the data acquired by the FCS measurement were converted to MSD curves using MATLAB software. The thesis discusses the influence of the experimental parameters on the shape of the MSD curve. The results showed that the number of particles and autocorrelation function have the most significant effect.
Biotechnological production of sophorolipids
Šimšová, Veronika ; Sedláček, Petr (referee) ; Obruča, Stanislav (advisor)
This diploma thesis deals with the microbial production of sophorolipids by the Starmerella genus yeasts. The theoretical part of the thesis includes general characteristics of biosurfactants with the focus on sophorolipids. There are described the options of biotechnological production of sophorolipids and fields of their possible applications. Furthermore, the theoretical part deals with the describtion of Starmerella bombicola yeast, which is often used for biotechnological production of sophorolipids. Six strains of the Starmerella genus were cultured in the basic medium suitable for sophorolipid produsction. The amount of produced sophorolipids was tested by the emulsification capacity assay, solubilization of crystalline anthracene assay, measuring the surface tension by the Du-Noüy-Ring method and determination of the sophorolipid concentration by extraction with ethyl acetate. The purity of the extracted sophorolipids was inspected by the Fourier Transform infrared spectrosopy (FT-IR) Based on the results, the Starmerella bombicola CBS 6009 and the Starmerella anomalae CBS 14178 strains were studied in greater detail. They were cultured in several production media of different composition and the effect of the individual components on the ability of the sophorolipid production was monitored. Based on the results, it was evaluated that the composition of the medium has a great influence on the production ability of the strains. The highest production rate of sophorolipids was achieved in the basic production medium and so was in the medium containing molasses and Indian waste oil. The cultivation mode has great effect on the sophotolipid production rate. It has been found that when cultured in a bioreactor, the strains produced sophorolipids in a larger amount and of a different quality than in the shaker flasks.
Utilization of spectroscopy in study on stress-resistance of bacteria on the sigle-cell level
Köbölová, Klaudia ; Venerová, Tereza (referee) ; Sedláček, Petr (advisor)
This diploma thesis deals with the possibilities of stress resistance analysis of the Cupriavidus necator H16 and PHB-4 bacterial cells by spectroscopic methods and by testing the suitability of acridine orange as a viable dye. Based on research in literature, suitable analytical methods have been proposed, namely flow cytometer and fluorescence microscope. The first part of the experimental work was focused on the fluorescence microscope, which confirmed the basic character of acridine orange. Three stress factors, 50% and 70% ethanol, and acidic pH (pH = 1) were selected for viability monitoring. The bacteria fluoresced with green color after exposure to ethanol and red spots were found next to the cells, indicating their loss of integrity. In an acidic environment, the bacteria fluoresced red because of a partial DNA breakdown. The results were verified by the combination of propidium iodide with SYTO9 and the acridine orange suitability proved to be useful in this method. Image records were processed using image analysis. In the second part, acridine orange was used to monitor fluorescence using a flow cytometer. The result of the measurement was fluorescence expressed as histograms for individual channels, where fluorescence was characterized by median and mean intensity. By comparing the methods used, the acridine orange appears to be a more suitable fluorescent dye for the microscope than for a flow cytometer in which it was more difficult to obtain cell viability information. In the last part of the experimental work interesting photophysical properties of acridine orange were investigated.
Utilization of thermal analysis in the study on effects of microbial inhibitors
Bošeľová, Miriam ; Obruča, Stanislav (referee) ; Sedláček, Petr (advisor)
This diploma thesis deals with the use of thermal analysis in the study on effects of microbial inhibitors. The main aim of this work was to determine the utilization of the method, which is mainly used in different fields of science and research. Three bacterial strains: Cupriavidus necator H16, its mutant strain Cupriavidus necator PHB-4 and Halomonas halophila, were used as model microorganisms. The inhibitory effect of levulinic acid on growth and metabolic activity was monitored by microcalorimetry. It was found that bacteria were able to adapt to levulinic acid to a certain concentration - Cupriavidus necator to 5 g/l and Halomonas halophila to 2 g/l. The thermal analysis results were compared to a conventional method, which is commonly used to study the growth of microorganisms.
Insertion of polyelectrolyte additives in the hydrogel matrices - influence on the mechanical and transport properties
Dušenková, Alica ; Klučáková, Martina (referee) ; Sedláček, Petr (advisor)
The main aim of the diploma thesis is to investigate the influence of incorporated polyelecrolyte additives on the mechanical and transport properties of hydrogel. Hydrogels, based on polyvinylalcohol, were selected for these experiments. Gelation of polyvinylalcohol can be induced physically or chemically. The aim was to investigate the influence of sodium alginate, sodium polystyrene sulfonate and sodium polyglutamate. Mechanical properties were studied by rheology, through viscoelastic properties. Transport properties were analyzed by using two methods: diffusion pair and fluorescence correlation spectroscopy.
Preparation and Characterization of Mechanical Properties of Artificial Synovial Liquids
Hrochová, Eliška ; Sedláček, Petr (referee) ; Kalina, Michal (advisor)
This bachelor thesis deals with the optimization of preparation of artificial synovial liquids. The main subjects of study are the mechanical properties of real and artificial synovial fluid samples. DLS microrheology, thermogravimetric analysis (TGA) and infrared spectroscopy (FTIR) were used for characterization. The theoretical part of this thesis is represented by a literature research of a methods of preparation of artificial synovia and summary of definitions of rheological terms. The experimental part focuses on the preparation and characterization of the artificial synovial liquids originating from the published patent US 8716204. In the framework of the bachelor thesis, this preparation was optimized in several partial steps (method of dispersion of components, choice of molecular weight of hyaluronic acid, nature and ionic strength of used dispersion medium). The prepared optimized sample of synovial fluid was in following experimental characterization steps compared in terms of material characteristics and mechanical properties with the real horse synovial fluid sample. By modifying the process based on the aforementioned patent, an artificial synovial fluid could be formed. That meets the viscoelastic nature of the real matrix and that is stable over time.
Study on biotechnological potential of Pseudomonas thermotolerans
Vašířová, Kristýna ; Sedláček, Petr (referee) ; Obruča, Stanislav (advisor)
The aim of this bachelor‘s thesis was to evaluate biotechnological potential of the bacterium Pseudomonas thermotolerans. The ability of bacterium to produce polyhydroxyalkanoates (PHA) and biosurfaktants was examined. Theoretical part deals with characteristic of extremophilic bacteria, PHA and biosurfactants. In the experimental part, the bacterium was tested for the presence of gene that catalyzes the synthesis of mcl-PHA (phaC1), using molecular technique PCR. Presence of the gene was confirmed by the experiment. Based on the result, PHA production conditions were optimized, such as selection of ideal media for production, suitable cultivation temperature and precursors. However, non of the tests confirmed the ability of production. Another of the experiments was to examine the bacterium’s ability to produce biosurfactants. Testing was realized in a suitable mineral medium with different carbon sources. Demonstrable production of biosurfactants was only on mineral medium supplemented by yeast extract and fructose. The thin layer chromatography (TLC) demonstrated, that the bakterium produces a mixture of monorhamnolipids and dirhamnolipids. However, higher portion is represented by dirhamnolipids.
Utilization of spectroscopical methods in the study on interaction of natural organic matter with organic ions
Prisažný, Adam ; Smilek, Jiří (referee) ; Sedláček, Petr (advisor)
This bachelor thesis deals with the interaction of humic acids with organic ions and effect of chemical modification of humic acids on this interaction. Rhodamine 6G was used as a model organic ion. The interaction were studied by spectroscopy methods. Results showed that the bond between the reactants was not primarily dependent on carboxylic functional groups of humic acids. Fluorescence experiments indicated static quenching mechanism and differential UV-VIS spectroscopy demonstrated the existence of - interactions.

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