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Thermal phenomena modeling of air electronic unit
Ančík, Zdeněk ; Toman, Jiří (referee) ; Vlach, Radek (advisor)
This thesis is focus on thermal analysis of aircraft electronic devices and their cooling possibilities. The two analytic methods of thermal analysis are applied on two particular technical objects. The laboratory experiment of non-contact temperature measurement method is applied on real unit. The results of simulation are compared with results of experiment.
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Study of influence of organic dye structure on their decomposition in the diaphragm discharge in liquids
Pajurková, Jana ; Fasurová, Naděžda (referee) ; Kozáková, Zdenka (advisor)
The main goal of presented thesis is to study the influence of organic dyes structure on its degradation in diaphragm discharge in liquids. Diaphragm discharge is a kind of non-thermal plasma that can be generated in liquids by the application of high voltage. In plasma channels (so-called streamers), many physical and chemical processes are formed. High electrical field, shock waves and last but not least emission of electromagnetic waves in the range of visible and ultra-violet radiation appear among physical processes. The most important chemical process is generation of active species. These species initiate chemical reactions and could attack molecules of organic compounds contained in water solution. The reason why organic dyes were chosen in this study is its visible destruction, because it is related to its decolouration. Further, UV-VIS spectroscopy for the determination of concentration during the experiment can be used. Organic dyes are good models of organic substance often contained in waste water and for which removal classical biological, chemical and physical methods aren’t sufficient. Selected dyes were mostly from the group of azo-dyes: Acid Red 14, Acid Red 18, Acid Yellow 23, Direct Blue 53, Direct Red 79, Direct Red 80, Direct Yellow 29, Food Yellow 3 and further, Acid Blue 74 (indigotic dye) and Direct Blue 106 (oxazine dye). Experiments were carried out in a special batch discharge reactor with the anode and the cathode spaces divided by a non-conductive barrier, where the diaphragm with a pin-hole was placed. Measurement showed different removal in the anode and cathode space. We have supposed it was caused by different streamers features and energetic conditions. Dyes were decomposed with higher efficiency in the anode space where the final concentration reached 40 % of the initial concentration while it remained about 90 % in the cathode space. In this thesis the influence of dyes structure on the dye decomposition by electrical discharge was investigated. Dyes consisted of small molecules and dyes with many substitutes bounded on aromatic ring were decomposed more easily than dyes consisted of big molecules. The shift of characteristic wavelength on both directions (to shorter as well as longer wavelength) was observed during the experiments especially when the Direct dyes were decomposed. This phenomenon was probably due to the formation of intermediate product, which have different characteristic wavelength than the primary compound. In general, colourfulness is given by long conjugated systems of double bonds with substitutes bounded on an aromatic ring. Each change in the molecule structure provides the colour change and this could be the possible reason of the shift of characteristic wavelength. The other task was the comparison of degradation process efficiency by the mean of electrolysis and diaphragm discharge. Results showed that electrolysis (30 W) was more convenient for degradation of dyes consisted of small molecules while diaphragm discharge (130170 W) suited for complex molecules. For degradation of small molecules, oxidation on the anode assumed to be the most effective process that is initiated by electrolysis. For degradation of big molecules, attack of active species produced by the discharge is necessary.
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Abstract Book URSI International Symposium Endogenous Physical Fields in Biology
Pokorný, Jiří
Book of Abstracts contains 65 abstracts of papers whose majority was presented at the symposium "Endogenous Physical Field in Biology" whose program was focused mainly on: a/ Generation of the endogenous electromagnetic filed by cellular and subcellular protein structures /e.g.microtubules/, b/ Biophysical problems of interaction of biological systems with exogenous electromagnetic fields. Some new methods used in photodynamic and hyperthermic therapy of malignant tumors are described too.
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The stability of biologically active compounds in elderberry (Sambucus nigra L.) inflorescence during processing
SUCHÁ, Renata
This thesis examines the stability of rutin in the inflorescences of the elder during processing. Elder (Sambucus nigra L.) is a medicinal plant that was used for medical purposes as early as in the Middle Ages. Both flowers (Flos Sambuci) and fruit (Fructus Sambuci) of the elder are on the list of official medicinal products of the State Institute for Drug Control. The main active phenolic substance is flavonoid rutin. Flavonoids are phenolic substances of plant origin. Among the best known properties of these substances is their antioxidant activity. They protect the low density blood lipoproteins from the oxidation modifications that cause the development of arteriosclerosis and hypertension. As a medical plant, the elder is used especially for the preparation of a medicinal drink. It is also commonly used as a material for the preparation of syrup. This product serves as a basis for a refreshing and tasty drink and lately is has also started to be sold in shops. For comparison, five single-flower syrups from the elderflower by different producers were bought. A method of preparation of the elderflower syrup was devised, based in one case on frozen elder inflorescences and in the other on dried inflorescences. The plant material came from wildly growing shrubs and it was collected in June 2013. Altogether, 8 syrups were prepared in the laboratory, 4 of them from fresh material and 4 from dried material. Two different methods were used. The first one was based on extraction using sugar solution, the second one on extraction using water solution where sugar was added afterwards. Another added substance was ethanol. The method for measuring the amount of rutin in the samples was a combination of two extraction steps. The first step was the usual exraction using aqueous methanol and the second step was extraction using a solid sorbent (SPE). The analysis of fresh and dried material concluded that dried elderflowers contain many times more rutin than fresh elder. Among the commercially produced syrups, the "Kitl Syrob Bezový" contained most rutin; a little less rutin was found in "Hamé Bylinný sirup Bezový květ". The concentration of rutin in the syrups prepared in the laboratory was much higher than in the commercial products. By using different methods of syrup preparation and their subsequent analysis, it was found that the syrups prepared from the dried inflorescences contained a higher amount of rutin than the syrups produced in the same way, but from frozen material. Addition of a small amount of ethanol had no effect on extraction of rutin from inflorescences. Free quercetin, which indicate a decomposition of rutin, wasn´t found in any of produced syrups. The produced syrups were used for the preparation of a drink and then underwent sensory analysis. The paired two-sided preference test included pairs of drinks consisting of a fresh elder drink and dried elder drink. The results showed that the evaluators preferred syrups from dried elderflowers in two of the cases, while in the other two evaluated pairs, the results were not statistically significant. In all cases, the evaluators most often found small and middle differences. The gained results show that the best method of syrup preparation uses dried plant material and sucrose solution as the extraction agent. The syrup prepared in this way contained most rutin and at the same time showed the smallest losses of this substance, which is beneficial to human health. Furthermore, it also tasted better in comparison with syrup prepared in the same way, but from fresh material.
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Hyaluronan ionocomplexes for cosmetic and farmaceutical applications
Cimalová, Jana ; Obruča, Stanislav (referee) ; Pekař, Miloslav (advisor)
This bachelor thesis is focused on the study of a system of cationic surfactant – hyaluronan. Using fluorescent spectroscopy the critical micellar concentration of Carbethopendecinium bromide (Septonex) was determined in three environments – water, 0,15 M NaCl, and buffer PBS, with three fluorescent probes – pyrene, perylene, and nile red. It was found that the physiological environments (buffer and NaCl) reduce the value of CMC about one order. During the experiments with native hyaluronan, precipitate and gel formation were observed. The following part dealt with aggregate behaviour of the new biologically acceptable amphoteric surfactant tetradecylfosfocholine (TPC) in the environment of water and NaCl according to the increasing molar molecular weight of hyaluronan. As a fluorescent probe perylene was used. These measurements showed that the molar molecular weight or a change of ionic force has no effect on the value of CMC and therefore there are no interactions with hyaluronan. The last surfactant to study was 1,2-dihexadecanoyl-3-dimetylammonium-propan (DPTAP), which is water insoluble. DPTAP is soluble in chloroform, but after evaporation of chloroform and after addition of hyaluronan, it precipitated. The results so far, have confirmed that in terms of research of aggregation by fluorescence spectroscopy the new cationic surfactants TPC and DPTAP are not suitable for complexation with hyaluronan.
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Testing of liquid fuels atomizers
Suchánek, Petr ; Skryja, Pavel (referee) ; Kermes, Vít (advisor)
This thesis is dealing with testing of two atomizers in combustion of liquid fuels and natural gas. There is a simple analysis of problems, principles and methods of atomizing liquids executed. Problem of pneumatic atomizing liquids is also described in detail. In the next chapters there is a plan and running of testing processed. Overall behavior of the atomizers and flame is evaluated from the outcome measurement and the power characteristics of atomizers and influence of GLR on the quality of combustion are determined. Overall rating of the testing is presented in conclusion this thesis.
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Cavitation assessment from flow rate drop and high-frequency pressure pulsations.
Šebek, Miloš ; Hudec, Martin (referee) ; Habán, Vladimír (advisor)
Main issue of this master´s thesis deals with high-frequency pulsations caused by cavitating hydraulic components (in this case nozzle and throttle valve). In first measurement on the nozzle was not a high-frequency sensor set in the way, so the evaluation was incorrect. After re-setting of the way was the nozzle measured again and the pulsations were evaluated correct this time. During the last measurement was the sensor located behind the throttle valve, which was with gradual opening and cavitation treatment measured. Resulting dependencies worked out on time dependence. A special mathematical method, Fourier transformation, was used. It transformed pressure amplitudes into frequency dependence. Evaluation of dependecies is the basic step for frequency band assesment, in which the cavitation on particular components happens.
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Design of polymerconcret frame of production machine
Lábus, Miroslav ; Pavlík, Jan (referee) ; Holub, Michal (advisor)
This work describes the construction of polymer - concrete frame of a machine tool. In particular it deals with the proposal of cast iron frame for the surface grinding machine BHP from the company KMS Brno, which should at all point replace the original cast iron frame of the same machine. The whole work is divided into two sections. First section consists of the research including a brief mention of the grinding technology in the reference to the construction of the frame of the grinding machine. Further the work deals with the theoretical knowledge regarding construction of frames of the machine. Finally it describes issues related to the technology of polymer – concrete and the production technology of parts from this material. Second section of the work consists of an engineering proposal of polymer – concreted frame considering the requirement of the main functional dimensions related from the structural measures. Subsequently the system approach and the principals for transition to the polymer – concrete construction of the grinding machine are made. The work concludes with the analysis and comparison of the two concepts (cast iron frame and polymer – concrete) in the terms of the Finite element method.
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