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Monitoring the properties of phase change materials (PCMs) over time
Šikutová, Eva ; Doležalová Weissmannová, Helena (referee) ; Řezáčová, Veronika (advisor)
The bachelor's thesis deals with monitoring the properties of phase change materials (PCMs, Phase Change Materials) over time. The theoretical block is divided into two parts. The first part focuses on the characteristics of these materials, their preparation and use in various industries. The second part presents methods for measuring the properties of PCMs samples. In the experimental part of this work, PCMs with a known defined history were analyzed by the method of differential scanning calorimetry (DSC) and the obtained results were then processed and evaluated.
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Analysis of perfluorinated alkyl compounds in environmental matrices
Šimáková, Anna Marie ; Řezáčová, Veronika (referee) ; Mravcová, Ludmila (advisor)
The bachelor thesis deals with the still topical issue of perfluorinated and polyfluorinated substances in the aquatic environment. In the theoretical part, the production and use of PFASs, which has led to the spread of these pollutants into the environment, is first addressed. Then, their behaviour in the environment is presented, which, due to their properties, results in their persistence in the environment, their ability to accumulate in living organisms and, in the case of decomposition, the possibility of even worse impacts. Exposure can result in carcinogens, hormonal changes and various types of toxicity in living organisms. The theoretical part concludes with methods for possible extraction from different matrices and detection by a suitable analytical method. The experimental part deals with the optimization of parameters for the method of determination and extraction of perfluorinated and polyfluorinated substances from water. All parameters were optimized to achieve the highest possible recoveries with acceptable repeatability and to achieve the lowest possible limits of detection and quantification.
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The separation of microplastics from environmental matrices
Pařízková, Mia Victoria ; Řezáčová, Veronika (referee) ; Doležalová Weissmannová, Helena (advisor)
This bachelor’s thesis deals with methods of separation microplastics from soil and the follow up application of quantitative methods of gravimetry, ATR-FTIR and Py-GC/MS. Samples containing model soil and PET or PLA microplastics of different concentrations were prepared. These samples were separated using potassium carbonate solution of known density. The effectivity of separation was measured by gravimetry. The samples were also analysed using ATR-FTIR and Py-GC/MS methods the results of which were compared by correlation coefficients. It was found that ATR-FTIR is a more suitable method, thus it was used for analysis of prepared samples of ten different real soils and PET or PLA microplastics.
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Detached house in Opatovice
Řezáčová, Veronika ; Jelínek, Petr (referee) ; Dohnal, Jakub (advisor)
The aim of this bachelor’s thesis is to develop a documentation for building permit of a new-build single-family house. First part of this thesis focuses on architectural and structural design of detached house with separate garage. This part also contains building physics assessment and fire safety assessment. The house has a rectangular shape, two-storeys and it is roofed with a gable roof. On the ground floor, there is a wind lobby, a utility room, a hall with a staircase, a study, a small storage, a living room connected with a kitchen, a bathroom and a toilet. On the first floor, there is one master bedroom with a walk-in wardrobe, a bathroom and three children’s bedrooms. The structural system is designed as masonry composed of sand-lime blocks, external walls are insulated with EPS. Foundations and floor structure are designed as the cast-in-place reinforced concrete slabs and the roof structure is made of prefabricated elements. Second part contains the concepts of building services design and a documentation for building permit for the heating system. The main source of heat is an air-water heat pump. Domestic hot water is also heated by solar panels and the house is heated by floor heating. Ventilation is ensured by a mechanical ventilation unit with heat recovery. Rainwater will be collected in a storage tank and used for watering the garden. An energy performance certificate of the building is also included.
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Thermal properties of bio-materials for heat accumulation during phase transformations
Dvorská, Adéla ; Mravcová, Ludmila (referee) ; Řezáčová, Veronika (advisor)
This bachelor's thesis focuses on the study of the thermal properties of natural substances that may exhibit phase change material (bio-PCMs) characteristics and could be used in construction. The aim of this thesis is to conduct literature research on materials with the potential for heat accumulation during phase changes, analyse selected bio-materials using differential scanning calorimetry (DSC), and comprehensively process and evaluate the obtained results. In the experimental part of this thesis, a total of 23 substances were analysed. Based on the DSC analysis results, potentially suitable bio-PCMs were selected. These materials were further studied in terms of their response to changes in temperature conditions and their short-term stability.
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Study of the content of heavy metals in the tissues of wild animals
Stoček, Michal ; Řezáčová, Veronika (referee) ; Komendová, Renata (advisor)
In the Ženklava hunting ground, tissues of roe deer (Capreolus capreolus L.), wild boar (Sus scrofa) and European mouflon (Ovis aries musimon) were analysed. Samples were taken from liver, kidney and muscle. The samples were digested in a mixture of nitric acid and hydrogen peroxide by microwave irradiation and subsequently analysed by ET-AAS techniques (Pb, Cd, Cu), F-AAS (Zn) and AMA (Hg). The concentrations found by the analysis of each element were
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Environmental monitoring for production quality assurance
Minářová, Klára ; Köbölová, Klaudia (referee) ; Řezáčová, Veronika (advisor)
This bachelor's thesis deals with the topic of environmental monitoring to ensure production quality. Specifically, the attention was paid to the monitoring of the presence and development of the number of microorganisms in the air and on work surfaces in specific production areas at regular intervals. The number of microorganisms in the air was determined by the method for determining the microbiological burden of the air, and the concentration of microorganisms on the surface was determined by the method of imprinting the tested area on an agar plate with subsequent cultivation and counting the bacterial colonies according to the internal regulations. Monitoring is carried out by the control microbiological laboratory, which falls under the quality department of the given manufacturing company. The basis for the preparation of this bachelor's thesis was obtained during my intership in the control microbiology laboratory.
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Analysis of hazardous metals in rPET granulate
Souček, Elena ; Řezáčová, Veronika (referee) ; Komendová, Renata (advisor)
Production of polymer products has increased rapidly in recent decades. Especially in food industry as a packaging it gained a dominant position when it replaced previously used materials. Due to the direct risk for human health it is necessary to be careful and pay attention to their composition. It is also necessary to develop methods to properly recycle and reuse already used material, not only produce new products. This thesis deals with the study of the content of risk elements in PET regranulate. The samples were completely decomposed by microwave radiation in an environment of concentrated sulfuric and nitric acid. They were subsequently analyzed by atomic absorption spectrometry (AAS). Flame atomization technique (FAAS) was used to determine Sb and Zn and electrothermal atomization (ETAAS) to determine Cd, Cr, Pb, Cu and Ni. This method was also used to study migration of antimony from samples to food simulant under different conditions (temperature, pH). This thesis follows up on the thesis of Mrs. Kryštofová who studied recycled PET flakes.
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