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Analysis of the rheological properties of vegetable oils and their components
Divílek, Petr ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
This Master’s thesis is dealing with theoretical analysis of vegetable, mineral oils and synthetic fluids, and with measuring of density and viscosity of selected samples of electric insulating fluids. The main part of the thesis is focused on vegetable oils and their elements called fatty acids. Those are more detail described in separate capitols. In those capitols is described their utilization in engineering practice with focus on energetics, where vegetable oils are used in larger scale. In experimental part of the work is measurement of density and dynamic viscosity. Viscosity was measured on two different machines, first the Hoppler viscometer and on vibrating viscometer. Results of these measurement are evaluated in tables and graphs.
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Thermal degradation of alternative electrical insulating liquids
Vodička, Tomáš ; Kazelle, Jiří (referee) ; Frk, Martin (advisor)
This thesis deals with alternative thermal degradation of electrical insulating liquids. The theoretical part describes the current state of the problem, electrical insulating liquids, their classification and types. There are described properties of electrical insulating liquids, their models of aging and diagnostic methods in accordance with the appropriate standards. In the practical part are chosen by representatives of alternative electrical insulating liquids and there are determined their dielectric characteristics in the initial state. According to the measured values is chosen five candidates for which it is designed and implemented an accelerated degradation test. During the test are measured dielectric parameters of the selected oils. Measured dependencies are mathematically approximated. In conclusion, the results are compared and physically interpreted in view of oxidation stability.
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Dynamic viscosity of electroinsulating liquids
Míka, Petr ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
This work deals with persepective environmentally friendly electroinsulating liquids. Important properties of currently used electroinsulating liquids are listed. Physical nature of viscosity of liquids and its temperature dependance are described and methods of its measuring are listed. Also temperature dependance of density is described from physical point of view. Measurement of density and of temperature dependance of viscosity of chosen vegetable and mineral oils was performed. On the basis of this measurement was calulated the activation energy of these samples. Two methods of dynamic viscosity measurement were used for some samples.
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Study of rheological properties of alternative electro insulating fluids
Botlová, Simona ; Jirák, Josef (referee) ; Frk, Martin (advisor)
This master thesis deals with clasification of electrical insulating liquids and analysis their reological properties. Theoretical part describes viscosity and possibilities of its measurement, electrical and non-electricl properties of electrical insulating liquids and themselves electrical insulating liquids. Practical part describes measurement of viscosity and density of chosen vegetable oils, their components and transformer oils in wide temperature range. At the conclusion of the thesis, analysis of measurement results is done.
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Modern vegetable oils useful in food and cosmetics
Plachtová, Kateřina ; Mravcová, Ludmila (referee) ; Zemanová, Jana (advisor)
The aim of this Bachelor’s thesis was to make a literary research of currently most used vegetable oils in food technology, cosmetics and pharmaceuticals focusing on health benefits, possibilities of use. Two selected modern vegetable oils were specified that are currently a subject of research in respektive fields. The selected modern oils were carrot seed oil and raspberry seed oil. A literary recherche was drawn up dealing with these oils from the perspective of their composition, charakteristics, properties and use in food technology, cosmetics and pharmaceuticals. In the experimental part of the thesis the fatty characteristics of carrot seed oil and raspberry seed oil were determined: acid value, saponification value, ester number, iodine value, peroxide value. Also fatty acids present in the oils were identified and quantified using gas chromatography with flame ionization detector. Fatty acids were analysed as their methylesters. Derivatization was was performer by alkalic esterification using methanolic solution of potassium hydroxide. In conclusion, selected oils were compared in terms of fatty characteristics and fatty acid profiles. Fatty acid composition was also compared to fatty acid composition found in literature sources.
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Study of macerates of selected plant materials in oily bases
Masár, Martin ; Pořízka, Jaromír (referee) ; Zemanová, Jana (advisor)
The aim of this thesis was in terms of literary research describe the composition, production, impact on human health and diverse uses of vegetable oils and their herbal macerates in human life. Herbal oil macerates are actually a blend of oils and herbs, created to produce a product that combines the beneficial effects of oils with therapeutic effects of herbs. Avocado and almond oil were used in combination with herbs such as black elder, chinese tea tree and ginger. Each herb also affects to some extent the quality of oil, which was observed in the time dependence of acid number in herbal macerates compared to pure oils. The acidity of the oil is also significantly influenced by temperature and therefore one set of samples was macerated at room temperature and the other in a thermostate at 35°C. The time dependencies of the acidity number of the individual oils and macerates were plotted into graphs and compared. In most cases, the thermostate-stored oils and macerates obtained higher acidity than those stored at room temperature. The effect of the herbs on the acidity of the oil varied in the different types of macerates, with the highest acidity values being taken by macerates with black elder flowers and the lowest, most similar to pure oils, by macerates with black elder fruits. At the end of the experiment, total and free fatty acids from the last sampling (after 77 days of extraction) of macerates and oils at room temperature were analysed by gas chromatography. Again, there were some differences in the composition of total and free fatty acids in herbal macerates compared to pure oils. Some herbs affect the composition of individual fatty acids more, others do not affect it almost at all.
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Study of alternative electroinsulating liquids properties
Bannert, Tomáš ; Hylský, Josef (referee) ; Frk, Martin (advisor)
This bachelor´s thesis is dealing with the study of alternative electrical insulating properties of the materials used in the electronics industry, particularly liquids based on natural esters and especially their constituents in the form of higher fatty acids and esters. The work is divided into theoretical and practical part. The theoretical part deals with the characterization of vegetable oils, their constituents and mineral oils, their comparison in terms of electrical and non-electrical properties and current state of the use of vegetable oils and their constituents in the electronics industry. Further it’s dealing with analysis of diagnostic methods for these characteristics. In the experimental part were analyzed electrical and non-electrical properties of selected samples of vegetable oils, their constituents and mineral oils such as the density, the dynamic viscosity and the complex permittivity and its parts as relative permittivity and loss number. Evaluations of the results of each group are compared with each other.
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Production and characterization of cheese analogues with the addition of vegetable oil
Babištová, Lucie ; Zemanová, Jana (referee) ; Vítová, Eva (advisor)
This thesis deals with the production and characterization of cheese analogues, ie products in which some of the dairy components are mutually or completely replaced by a non-dairy component. Model samples of fresh cheese and analogues of fresh cheese (standard) with the addition of linseed and rapeseed oil were produced by a standard technological procedure in MENDELU Brno. The content of bound and free fatty acids, volatile (aroma) substances and sensory quality was monitored in the samples. The main focus was to evaluate the effect of added vegetable oil on the monitored parameters. The fats from the sample were extracted with a mixture of diethyl ether and petroleum ether. Fatty acids were converted to methyl esters by boron trifluoride-catalyzed acid esterification and subsequently identified by GC-FID. The analysis found a higher content of fatty acids in cheese analogues in comparison with the control sample, also the content of unsaturated fatty acids increased. The HS-SPME-GC-MS method was used for the identification and semi-quantification of volatile substances (aromatic substances). 56 volatile compounds were identified in the samples; The percentage of individual chemical groups differed significantly, the highest content was found in the control sample. Sensory evaluation was performed using a scale and a serial test. In all of monitored indicators (apparence, color, consistency, smell and taste) the control sample was evaluated as best. As for the analogues the taste and smell of used oils were detected, which was unpleasant for the evaluators. The obtained results show that the addition of vegetable oils increases the nutritional value of cheeses (higher content of unsaturated fatty acids), but reduces their sensory quality and overall consumer acceptability.
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Alternative Fuel Engines
Bilík, Michal ; Ramík, Pavel (referee) ; Dundálek, Radim (advisor)
This thesis deals with an overview of alternative fuels for road vehicles and their effect on ecology. This work also describes the specific characteristics and peculiarities of power units which run on alternative fuels, their advantages, disadvantages and shows examples of some vehicles.
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Studium vlivu lněného, konopného, mandlového, sezamového a arganového oleje na buněčné linie
Sisrová, Jitka
The diploma thesis deals with the influence of linseed, hemp, almond, sesame and argan oil on MDA-MB-231 and HaCaT cell lines. The results of the analyses show that the application of oils to cell lines can, to a certain level, inhibit the processes characteristic for tumour cells. Cytotoxic effects investigated by the MTT assay were demonstrated by all selected types of oils, except for almond. The degree of migration examined by the Scratch test in MDA-MB-231 cells was also inhibited by all types of oils, except for almond oil and, in the case of HaCaT, argan oil was the exception. The morphology of MDA-MB-231 cells was changed only by linseed and hemp oils, for the HaCaT cell line by all types of oils. In the inhibition of the formation of cell clones, examined by the clonogenic assay, all types of oils were successful in both cell lines. Haemolytic test showed the activity of hemp and sesame oil.
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