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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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Evaluation of stability of selected vegetable oils
Němečková, Lenka ; Lehocký,, Marián (referee) ; Zemanová, Jana (advisor)
This diploma thesis is focused on issues concerning the stability of selected vegetable oils which are used in cosmetic industry. The stability of eight oils without additives were determined by a differential scanning calorimeter. In the first phase, the temperatures of oil degradation were determined for different rates of heating, i.e. nonisothermal stabilities. They were consequetly used to calculate isothermal stabilities alias induction periods. The calculation of induction periods was completed by using integral isoconversional methods, which applied four different temperature functions. One of the temperature functions corresponded to Arrhenius equation while the others to non-Arrhenius functions. The confrontation of induction periods under standart conditions showed that an optimal temperature function to calculate oil stabilities is one of the non-Arrhenius functions in exponential form. We can state that all oils are degraded by similar, if not the same, mechanism. The specified stabilities, in periods of months, have proved the importance of using stabilizers and other additives in the commercial and technological use of vegetable oils.
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Changes of fatty acids content in vegetable oils during their storage
Bambasová, Lenka ; Hrstka, Miroslav (referee) ; Vítová, Eva (advisor)
The aim of the diploma thesis was the identification of fatty acids contained in vegetable oils by gas chromatography. Amount of fatty acids was monitored in dependence on the duration and conditions of storage. Conditions for storage were selected at room temperature and refrigerator temperature. In total fourteen oils were analyzed - avocado oil, pumpkin seed oil, grape seed oil, jojoba oil, corn oil, linseed oil, macadamia oil, almond oil, apricot-stone oil, olive oil, castor oil, rice oil, sunflower oil and soya bean oil. Gas chromatography was applied for identification and quantification of fatty acids. Methanol esterification method using potassium hydroxide catalysis was chosen for preparing of the samples of the fatty acid methylesters. Eight fatty acids were observed in the vegetable oils : myristic, palmitic, palmitoleic, stearic, oleic, linoleic, gama-linolenic and linolenic acids.
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Study of quality of different vegetable oils
Martinů, Michaela ; Janoušková, Eva (referee) ; Zemanová, Jana (advisor)
The aim of the diploma thesis was determined the particular fatty characteristics of various vegetable oils in dependence on their storage life and storage conditions. Storage conditions were defined by room temperature and coolroom temperature. The fourteen oils were used for analyses, namely linseed oils, castor oil, grape seed oil, almond oil, olive oil, jojoba oil, avocado oil, apricot kernel oil, corn oil, rice bran oil, macadamia nut oil, soya bean oil, pumpkin seed oil and sunflower oil. All tested oils were supplied by firm M+H, Míča a Harašta s.r.o. The fatty characteristics included the saponification value, the acid value, the iodine value and the thiobarbituric value. The ester values and the percentage glycerol content were counted on the basis of the saponification value and the acid value. Time dependences of all fatty characteristics were figured to graphs and they were compared on various storage conditions. The fatty characteristics indicated lower values in storage of oil samples in coolroom than at laboratory temperature.
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Plant oils for industry
Beran, Vojtěch ; Ficza, Ildikó (referee) ; Frýza, Josef (advisor)
This bachelor thesis describes usability of plant oils as liquid greases. The beginning of thesis follow up tribology problems and process of lubrication. The main section describes plant oils from perspective of their chemical composition and its closely related properties. In this thesis, plant oils are compared with another common liquid oils together with the comparison of its properties on specific application. In the conclusion, the thesis deals with summary of plant oils issues and with prospects for the future.
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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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Possibilities for utilization of selected vegetable oils in foodstuffs.
Krátká, Milena ; Vránová, Dana (referee) ; Zemanová, Jana (advisor)
The aim of this work was to find out and compare the composition of the chosen vegetable oils with regards to both the chemical composition and the pharmacological effects as the supplementary nutrition. All the oils selected contain large amount of the essential fatty acids, which has the positive effect on human health. Evening Primrose oil, borage oil and black currant seeds oil contain the large amount of the gama-linolenoic acid (GLA), which has the positive influence on the curing of the diabetes, menstrual syndrome, cancer, cardiovascular diseases, viral infections and skin disorders. Flax and hemp oil are excellent sources of the essential fatty acids in optimal ratio and are rich in other important substances, like phytoestrogenes and phytosterols. The lipids containing the high amount of the unsaturated fatty acids are predisposed to the oxidation during the storage. The oxidized essential fatty acids have the antimetabolic effect, which is working against the positive effect of original essential fatty acid. It is thus important and recommended to accompany the consumption of the polyunsaturated fatty acids (PUFA) with the antioxidants. In this work the effects of the antioxidants were also taken into account. From the oils selected the highest amount of the antioxidants can be found in Sea buckthorn oil, which contains the antioxidants like vitamin E, carotenoids etc. This work was also aimed at the literature review of the stabilization of the unsaturated fatty acids, technological production processes, reactions taking place in oils during their storage and the analytical methods used for the characterization of the oils.
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Basic ingredients of fatty phase and their influence on stability of cosmetic emulsions
Krätschmerová, Kateřina ; Souralová Popelková, Miriam (referee) ; Zemanová, Jana (advisor)
This bachelor thesis is focused on the problem of stability cosmetic emulsion. The aim of this thesis was to elaborate a literature review focused on ingredients of fatty phase and their influence on stability of cosmetic emulsions. Emulsions are heterogeneous two-phase dispersive systems. They are formed from two immiscible liquids: one constitutes the droplets which are dispersed in the other liquid. They are classified into emulsion O/W (oil-in-water), W/O (water-in-oil) and multiple emulsions O/W/O and W/O/W (oil-in-water-in-oil, water-in-oil-in-water). In the midst of basic ingredients of fatty phase range raw material of crude petroleum, vegetable oils, animal fats, waxes and sterols. Crude petroleum materials belong to stable components of lipid phase, whereas vegetable oil and animal fats are unstable components and have to be stabilized by adding of suitable stabilizer.
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Aromatherapy as part of relaxation techniques
VANDLÍČKOVÁ, Karolína
This bachelor thesis focuses on aromatherapy as a part of relaxation technique. Theoretical part discusses the field of relaxation and regeneration. Subsequently it describes characteristics of aromatherapy, its history and its importance to humans. Further I addressed the topic of vegetal and essential oils, that are crucial part of aromatherapy and relaxation massages. Practical part describes the whole process of enquiry that used standardized POMS survey questionnaire. Research sample consisted of ten people that took eight aromatherapy massage lessons each. Outcomes of the research confirmed that aromatherapy is a suitable alternative method for relaxation massages.
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