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Bioactive substances for face cream: Determination of stability of face cream incorporated with goat's milk
Dostálová, Tereza ; Sovová, Šárka (referee) ; Enev, Vojtěch (advisor)
The aim of this bachelor thesis is a stability trial of a skin cream incorporated with goat milk lyophilizates prepared in usual laboratory conditions. Firstly, the goat milk was denatured, to be further analysed via FTIR, elemental analysis and thermogravimetry. To compare the denaturation effect, measurements with native goat milk sample were performed as well. Next, an emulsion was prepared. First stability tests were performed using analytical centrifuge and the cream preparation procedure and component ratio was optimized. Stability trials were carried out at specified time intervals. Rheological properties – especially yield stress values and structure strength, determined by linear viscoelastic region and complex modulus – thermal endurance measured via differential scanning calorimetry and visual validation via optical microscopy and sample observation were tested and performed. Skin cream stability of sample stored at laboratory temperature was demonstrated, showing moderate sings of structure destabilisation. Product suitability for dry skin was proved by sensory analysis. The skin feeling was pleasant, and the cream moisturized the surface area, that it was applied to, according to evaluators. Visually, the emulsion appeared to maintain its properties during the experiment time range, it did not undergo a complete degradation of separation into two original phases, nor it was degraded, for example by mold.
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Thermal and microstructure analysis of binary eutectic system
Bielková, Kateřina ; Klepárníková, Eliška (referee) ; Adam, Ondřej (advisor)
This bachelor thesis deals with the analysis and verification of binary diagram of the Sn-Bi system. The theoretical segment of the thesis describes the common phase transformations and methods of their research, especially thermal analysis. The experimental part is focused on the analysis of six samples (four alloys and two pure metals). Analyses were performed by differential scanning calorimetry (DSC) and scanning electron microscope. The measured data were compared with the given binary diagram, with which it corresponds relatively well.
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Properties comparison of two products used for skating rink based on ehtylene-propylene-dien rubber
Kostková, Jana ; Kučera, František (referee) ; Bálková, Radka (advisor)
This master thesis deals with characterization of two black and white products based on ethylene-propylene-diene rubber (EPDM) used for skating rink. Products marked with A and are different in their diameter of circular tubes trough which cooling medium passes and also in the distance of these tubes. Both of materials were characterized in order to determine whether it is the EPDM and how are they different. The characterization methods were used: differential scanning calorimetry, thermogravimetric analysis, attenuated total reflectance Fourier transform infrared spectroscopy, tensile test, swelling test, thermooxidative test. The composition of both materials, including fillers and others additives is almost the same but difference is in structure of EPDM and probably also in interaction with fillers, what exhibits different mechanical properties, thermooxidative stability and thermal capacity. These differences which have been found are essential for long-term use properties of both materials.
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DSC evaluation of homogenity of Ni-Ti alloys ingots
Kuběnová, Monika ; Zemčík, Ladislav (referee) ; Dlouhý, Antonín (advisor)
Alloy NiTi with nearequiatomic composition of nickel and titan belongs to a group of metal materials with a shape memory effect (Shape memory alloys). NiTi alloys are a guite attractive materials not only as practical shape memory alloys with hight strenght and ductility but also as those exhibiting unique physical properties. The production of these matrerials is complying with chemical composition. Final charakteristics of alloy are influenced by these bounderies and also by mechanical-heat treatment. This work deal with DSC evaluation of homogenity of ingot structure of NiTi alloy containing 50,8 at.% Ni. The alloy was melted in Y2O3 cricible. In the end the results of DSC method are compared to the microstructure of alloy obtained by SEM and TEM methods.
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Dynamic Models of Power-Generating Modules
Kopička, Marek ; Máslo, Karel (referee) ; Procházka, Karel (referee) ; Eleschová, Žaneta (referee) ; Drápela, Jiří (advisor)
The dissertation thesis deals with the design of the concept and implementation of models of electrical power system elements with regard to the potential of the use of computer programs – simulations. The solution of the thesis focuses on the compliance simulations of power-generating modules according to RfG (Requirements for Generators), as a document which setting out the requirements for the connection of power-generating facilities and also focuses on the issue of smart grids and MAS (Multi-Agent Systems) respectively. The framework of the thesis is thus defined by the area of requirements for power-generating modules according to legislative requirements (not only RfG, but also related standards incl. DSC (Distribution System Code), CSN EN 50438 and CSN EN 50549), requirements for agent functionalities and power-generating module abilities to operate in synchronous and island operation, including transitions between them, the process of synchronization (phasing) and communication between the individual elements of the power system.
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Hydration of biocolloids - calorimetric study
Šméralová, Ester ; Pekař, Miloslav (referee) ; Klučáková, Martina (advisor)
Presented master's thesis focuses on the study of hydration of selected biocolloid substances, specifically humic substances (humic acids and fulvic acids), hyaluronic acid with three different molecular weight, chitosan and dextran. Interaction of biocolloids with water was studied by different methods. The effect of solubility, structure, functional groups in molecule on sorption and hydration ability of these biocolloids was investigated. In the case of hyaluronan the influence of molecular weight was also study. Differential scanning calorimetry DSC and perfusion calorimetry give results of heat of hydration, enthalpies and temperature of crystallization and melting. Thermogravimetric analysis TGA was used to determine the original moisture content of the samples.
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Testing of polymeric materials under climatic conditions of Antarctica
Mičkal, Petr ; Sluková, Michaela (referee) ; Krmíček, Lukáš (advisor)
The bachelor's thesis generally deals with polymer materials and evaluates the possibility of testing their resistance to extreme climates of Antarctica. Described herein are various polymer materials, their characteristics, structure, properties and more thorough and detailed descriptions of selected polymers. The next section describes the basic types of degradation these polymers are exposed to, when facing the extreme conditions of the Antarctic climate. The practical part contains evaluations of tests made on the degraded polymer materials that were collected in Antarctica during the southern Antarctic season of 2013-2014 by Ing. Bc. Pavel Kapler, Ph.D, who is a superintendent at the Czech scientific station JG Mendel.
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Ansible for Windows
Klíč, Jiří ; Očenášek, Pavel (referee) ; Trchalík, Roman (advisor)
The main purpose of this bachelor thesis is dealing with possibilities of automation of the computer management and acquisition of data about computers. This thesis focuses on automation of Windows-based computers managed by Linux operating system. The automation is performed by text user interface. It presents to the reader the used tool named Ansible and its components and usages. Here are discussed both methods of collecting of required data and their meaning and interpretation. Some data which are collected in this work are static, the rest of them use to change their values by time. There are also discussed possibilities how to manage the software equipment of the computer.
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Identification of PET particles in soils and their influence on the environment
Šudomová, Lucie ; Svěrák, Tomáš (referee) ; Slovák, Václav (referee) ; Kučerík, Jiří (advisor)
This thesis is focused on several issues connected with plastics and their impact on the environment. Although plastics are produced for a relatively short time, they have taken a dominant position in almost all industries and aspects of everyday life. However, this causes significant challenges related especially to the waste management. If plastics are not handled properly, they can contaminate the environmental compartments where they are gradually defragmented and degraded, and macro and microplastics are formed. Both qualitative and quantitative analysis of microplastics in soil is a big challenge. In this work, it is introduced a new method based on mutual relationships between soil components called Soil Universal Model Method (SUMM). The method allowed to identify and quantify some types of microplastics in the untreated soil. It appeared to be effective in the analysis of PET, PVC and PP. A pilot study on the influence of PET microplastics on soil revealed negative effects, which include soil organic matter deterioration and faster desiccation. In addition, it was observed a gradual assimilation of PET into the soil matrix, and possible degradation, in particular at low pH values. To identify the origin of PET fragments occurring in nature it was developed a method based on PET thermophysical properties (determined using Differential Scanning Calorimetry, DSC) and advanced statistical methods. This method appeared to be effective also for the assessment of PET quality in recycling loop and classifies the PET into four groups. It was also found that controlled thermal degradation under laboratory conditions does not correlate with natural PET degradation (aging). A method based on spectroscopic parameters (FTIR) is also presented here, but it did not achieve such unambiguous results as using DSC, because it determines the molecular structure of the polymer, which proved to be insufficient for identifying changes during the PET recycling cycle.
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Stability of natural oils used in cosmetics and pharmaceuticals
Milerová, Helena ; Enev, Vojtěch (referee) ; Hurčíková, Andrea (advisor)
The bachelor's thesis deals with the issue of stability of selected plant oils used in the cosmetic industry. Six oils were subjected to analysis using differential scanning calorimetry (DSC), which determined the oxidation onset temperatures for all samples. The aim of the thesis is to evaluate the use of the DSC method for obtaining data on the thermo-oxidative stability of plant oils. For comparison, the samples were also measured using the Rancimat method, a commercially established procedure in which the samples were exposed to elevated temperature using air flow. The results yielded induction periods, which indicate the time until the sample starts to oxidize. After measuring the samples using both methods, the oils were ranked according to their oxidative stability from the most stable to the least stable. The resulting sequences from both methods were nearly identical. DSC has proven to be a suitable method for measuring the thermo-oxidative stability of plant oils.
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