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Study of the influence of additions on the durability of aerated concrete
Halešová, Adéla ; Voves, Jiří (referee) ; Hubáček, Adam (advisor)
The aim of this work is to summarise and consider the possibilities of using admixtures and their influence on the durability of aerated concrete.This bachelor's thesis is based on research findings concerning aerated concrete. Furthermore, it deals with the study of inert and active additions. The experimental part is focused on testing trial samples with the addition of admixtures. It examines what is the rate of the possible chosen physically-mechanical features such as the rate of air density, the durability of surface against the effect of water and chemical defrosting substances and achieving the required strength.
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Development of cementitious screeds of higher use properties
Kardošová, Romana ; Přikryl, Jan (referee) ; Hela, Rudolf (advisor)
The aim of this paper is to summarize and evaluate properties of polymers modified modified mortar, their durability and the possibility of surface treatment. Recently, the requirements for additional surface treatment of architectonal concrete are increased and the application of polymer-modified mortar can accelerate and simplify the realization of visible concrete. Polymer-modified mortar with the addition of powder photocatalysts can significantly reduce and thus increase the availability of photoactive concrete structures. The experimental part deals with the addition of photocatalyst to the polymer-modified mortar and the subsequent assessment of the photocatalytic properties, the possibility of modification cement mortars with anorganic pigments and the application of transparent coatings for the enhancement of color saturation and resistance.
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Production of Selected Microbial Metabolites and Energy Using Different Waste Materials
Petrik, Siniša ; Rychtera, Mojmír (referee) ; Němec, Miroslav (referee) ; Pekař, Miloslav (referee) ; Márová, Ivana (advisor)
Pro zpracování a nakládání s odpadními substráty lze použít řadu postupů a možností. Stále se rozšiřující spektrum metod a technologií umožňuje další využití materiálů a energie ve formě obnovitelných zdrojů. Jedním z řešení pro zpětné získávání některých odpadních materiálů je využití tzv. bílé (průmyslové) biotechnologie, která zahrnuje praktickou aplikaci metabolických aktivit celé řady různých mikroorganizmů včetně jejich specifických biologických drah k produkci látek s vysokou přidanou hodnotou. V předložené práci screeningového typu bylo pro zhodnocení odpadních surovin využito několik druhů mikroorganizmů kultivovaných za různých specifických podmínek včetně kultivace na odpadních materiálech získaných zejména ze zemědělství a potravinářství. Cílem bylo získání vybraných typů průmyslově cenných metabolitů, případně energie. Předložená studie byla zaměřena na srovnání růstu a produkčních vlastností několika kmenů karotenogenních kvasinek rodu Rhodotorula, Sporobolomyces a Cystofilobasidium, kultivovaných v médiích s obsahem glycerolu (technický a odpadní glycerol), dále v médiích obsahujících pšeničnou slámu, hydrolyzovanou slámu zpracovanou v hydrotermálním procesu při vysoké teplotě a zbytky po filtraci hydrolyzátu. Dalším testovaným odpadním substrátem byla syrovátka. Všechny testované kvasinky byly schopny využít glycerol jako jediný zdroj uhlíku. Produkce biomasy při kultivaci na technickém glycerolu se více či méně přibližovala kontrole (cca 7 - 10 gl-1), zatímco při kultivaci na odpadním glycerolu byla produkce vyšší (10.9 - 14.5 gl-1). Produkce karotenoidů a ergosterolu byla vyšší v glukózovém médiu než v médiu s obsahem glycerolu. Všechny testované kvasinky byly rovněž schopny produkovat neutrální lipidy, a to v rozmezí 11 - 15 %, s výjimkou C. capitatum, kde produkce dosahovala více než 22 % obsahu neutrálních lipidů. Pšeničná sláma a produkty z ní připravené se ukázaly být využitelnými substráty s vysokým potenciálem pro produkci biomasy i metabolitů, a to zejména u kmene S. roseus. Syrovátka, jako odpadní produkt mlékarenství, byla účinně využita jako substrát pro kokultivaci karotenogenních kvasinek a bakterií mléčného kvašení. Kokultivační proces může vyvolat nadprodukci pigmentů a ergosterolu, přičemž získaná biomasa díky obohacení o bakterie L. casei dosahovala vyšší kvality. Za účelem energetického využití mikrobiálního metabolismu formou mikrobiálních palivových článků, tzv. „Microbial Fuel Cell“ byla aplikována směsná kultura bakterií získaných z čistírny odpadních vod. Tyto mikroorganizmy hrají významnou roli při výrobě elektrické energie a současně také při čištění odpadních vod. Elektřina je generována přímo z organických látek přítomných v kultivačním médiu a lze ji použít pro provoz čistírny samotné a případně i pro další aplikace.
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Biochemical changes accompanying the aging of red wine
Vacková, Tereza ; Hudeček, Jiří (advisor) ; Entlicher, Gustav (referee)
Flavonoids are plant secondary metabolites, which belong to several groups varying in their chemical structure. Anthocyanins and tannins are important flavonoid components of wine that are responsible for its color, taste and other sensory properties. The concentration of anthocyanins in wine is affected by grape variety, processing technology, and climatic conditions. In this Thesis, we studied the changes in color and in related chemical composition, using three non-commercial samples of red wine: Svatovavřinecké (year 2010 and 2012), and home-made wine (prepared without addition of SO2). These changes in color were determined using standard colorimetric method (CIELab) and also a simplified two-parametric spectrophotometric method (tint/color density). The content of anthocyanins was followed using analytical RP-HPLC method. In paralel, simplified oenologic methods for estimation of phenolic compounds were used. Generally the wine samples changed color to darker tint. Chemically, this was caused by polymerisation reactions between anthocyanins and phenolic compounds. This led to the formation of stable pigments characterised by a higher absorption maximum at longetr wavelength, hence a darker tint. Key words: anthocyanins, color, red wine, phenolic compounds, malvidin-3-glucosid, polymeric reactions,...
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Identification of microbial pigments in evaporites using Raman spectroscopy: implications for astrobiology
Vítek, Petr ; Jehlička, Jan (advisor) ; Marshall, Craig P. (referee) ; Vandenabeele, Peter (referee)
Raman spectroscopy is a powerful tool for identification both inorganic and organic compounds including microbial biomolecules. Together with the fact, that it is considered to be the important nondestructive instrument for use on Mars within future robotic missions, it is necessary to assess its capabilities in scenarios relevant for both Martian and terrestrial conditions. In this work, the potential of Raman spectrometry was tested - including both bench-top laboratory systems as well as portable counterparts - to detect traces of life within evaporitic matrices through biomolecular identification. Due to their chemical and physical nature resulting in optical properties, pigments are important organic compounds in Raman spectroscopic analysis using visible excitation. Hence in this work we have focused on the Raman spectroscopic identification of pigments as biomarkers with relevance for investigation of life in both extreme terrestrial and potentially extraterrestrial environments. Results of methodical work are presented in Appendices I to III, dealing particularly with β-carotene as a model carotenoid pigment. The concentration limits of this biomarker in three different evaporitic matrices (halite, gypsum and epsomite) have been determined for artificially prepared powdered mixtures alone...
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Study on metabolism of polyhydroxyalkanoates in bacterium Rhodospirillum rubrum
Pacasová, Viktorie-Alexandra ; Byrtusová, Dana (referee) ; Slaninová, Eva (advisor)
The present thesis focuses on polyhydroxyalkanoate (PHA) production in Rhodospirillum rubrum, comparing wild-type PHA-producing (R. rubrum) and mutant PHA-non-producing strains in terms of cell morphology. These bacterial strains were also subjected to selected stresses and the effect of PHA on the stress response was determined using advanced analytical techniques. The two strains used were first cultured under different conditions differing in light access, oxygen, culture time and substrate. The effect of culture conditions and PHA content on resistance to selected stressors - elevated temperature, osmotic stress and repeated freezing cycles - was then investigated. First, strains were cultured under aerobic conditions in the dark for 48 and 72 h. Viability of these samples was examined using a fluorescent probe (propidium iodide) by flow cytometry, while cell disruption was examined by electron microscopy. Furthermore, a similar experiment was performed in which the wild-type and mutant strains were cultured under microaerobic conditions in the light for 120 h to produce pigments (bacteriochlorophyll a and carotenoids). UV-VIS spectroscopy was used to determine the extracted pigments. The effect of culture time and conditions on the stress response was also determined for both bacterial strains by flow cytometry and electron microscopy. In the experimental part of the work, the ability to produce the copolymer P(3HB-co-3HV) was confirmed in a wild-type strain of R. rubrum. The hypothesis of the protective property of PHA granules when exposed to freezing cycles was also confirmed. In contrast, the protective function of PHA was not proven when exposed to osmotic stress.
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Extreme environment of the Atacama Desert: Geology, Extremophiles, and its connection to Exobiology
Jíra, Stanislav ; Culka, Adam (advisor) ; Vítek, Petr (referee)
Because of the position in the subtropical climate belt, high altitudes, cold Humboldt Current, Andean rain-shadow, and a few other factors, the Atacama Desert is known for its hyper-arid conditions which are persisting here for a few tens of millions of years. That is why this place is called the driest non-polar place in the world. Aridity is present here since Mesozoic. Because of these conditions, Atacama was thought to be completely inhabitable and inappropriate for any life forms. Despite all the limiting factors, microbial life here exists. Microorganisms have created adaptations in the forms of specialized metabolisms, proteins, and most importantly in form of photoprotective pigments. Except for the structural mechanisms, extremophiles can choose a strategy of living evaporitic minerals, which are quite common in Atacama. For understanding these forms of life many scientific methods are used, for example Raman spectroscopy. Methods that are used here are often used also in extraterrestrial conditions, mainly on the planet Mars, which shares with Atacama few similarities (e.g., some evaporitic minerals). The study of adaptations and capabilities of extremophilic microorganisms can help to broaden the knowledge and understanding of how incredibly resilient life is. Keywords: The Atacama...
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Biochemical Aspects of Artwork Restoring
Boledovičová, Petra ; Hudeček, Jiří (advisor) ; Kubíčková, Božena (referee)
The following bachelor thesis is focussed on findings on the field of art restoring in connection with its biochemical aspects. In itroduction is resumed brief history of art restoring and generally defined terms of preservation, restoring, art and paint. For better understanding basic paint techniques (aquarelle, gouache, tempera and oil painting), strata sequence and instruments and materials commonly used for art work are mentioned. Most frequently used organic and inorganic pigments are briefly mentioned, however this thesis is mainly focussed on applied organic compounds - lipids, proteins, polysacharides and terpenoids - its composition, characteristics, usagea nd possible interactions. The following thesis is written in czech. Key words: restoring, art work, paint, organic binders, lipids, proteins, polysacharides, terpenoids
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