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Hydrogels of Humic Acids
Cihlář, Zdeněk ; Lehocký,, Marián (referee) ; Pospíšilová,, Lubica (referee) ; Kučerík, Jiří (advisor)
Huminové kyseliny představují hlavní součást půdní organické hmoty. Jedná se o všudypřítomné sloučeniny s komplexní chemickou a fyzikálně-chemickou strukturou. Předkládaná práce shrnuje několik způsobů modifikací huminových kyselin provedených za účelem úpravy jejich vlastností. V první části byl studován vliv vzdušné oxidace lignitu na velikost výtěžku a fyzikálně-chemický charakter produkovaných regenerovaných huminových kyselin. Druhý krok představoval snahu stabilizovat strukturu lignitických huminových kyselin a zlepšit zádrž vody. Bylo provedeno síťování pomocí formaldehydu a karbodiimidů, které předpokládá vznik nových kovalentních vazeb v různých částech struktury huminových kyselin. Produkce zesíťované struktury byla motivována snahou vytvořit systémy podobné hydrogelům, založené na huminových látkách s možností úpravy jejich reaktivity a retence vody. Chemické složení a fyzikálně-chemické vlastnosti připravených vzorků byly studovány různými metodami, mezi nejdůležitější patří DSC a NMR relaxometrie. Chemické složení bylo studováno pomocí FTIR a elementární analýzy za účelem posoudit a porovnat změny s původním neupraveným vzorkem. Stability vzorků byly stanoveny pomocí termogravimetrie. Nejdůležitějším sledovaným parametrem této práce byla změna hydratačních charakteristik. K jejich studiu jsme vyvinuli a aplikovali několik nových termoanalytických a NMR relaxometrických přístupů. Ve snaze napodobit přírodní procesy byla studována sorpce vody huminovými kyselinami z prostředí s kontrolovanou vzdušnou vlhkostí. Byly pozorovány kvalitativní a kvantitativní hlediska sorpce vody. Zesíťování za použití formaldehydu způsobilo snížení sorpční kapacity vlhkosti. Tato změna je připisována separaci funkčních skupin a menší strukturní kompaktnosti. Zesíťované huminové kyseliny dále vykazovaly rychlejší příjem vody a přibližně třikrát větší kapacitu zádrže vody než původní huminové kyseliny. V případě použití karbodiimidu (ve vodě rozpustného N-Ethyl-N-(3-dimethylaminopropyl)karbodiimidu (EDC)) obsahovaly výsledné produkty 14–40 % původních karboxylových skupin. I přesto tyto látky překonaly schopnost sorpce vlhkosti původního nemodifikovaného vzorku o 10–14 % po kondiciaci v prostřední se 100% relativní vzdušnou vlhkostí. Navzdory rigidnější struktuře vykazovaly EDC deriváty rychlejší bobtnání a dosáhly téměř stejné kapacity zádrže vody po 18 dnech jako původní vzorek. Vzorky modifikované karbodiimidy vykazovaly známky degradace již po 3–9 dnech což částečně snižuje jejich využitelnost. Získané výsledky naznačují, že kapacita zádrže vody, kinetika bobtnání a schopnost sorpce vlhkosti huminových kyselin nejsou výhradně určeny koncentrací karboxylových skupin, nebo dalších polárních fragmentů, ale také jejich vzájemným rozmístěním a distribucí velikosti pórů na povrchu a také uvnitř struktury. Získané poznatky této studie mohou sloužit například k produkci půdních kondicionérů založených na huminových kyselinách, tj. remediačních preparátů s požadovanými, ale především nastavitelnými schopnostmi poutat a následně uvolňovat vodu do okolního prostředí. V neposlední řadě přispějí uvedené závěry ke zkvalitnění základního porozumění procesu hydratace v modifikovaných a původní vzorcích, což je přínosné ve vztahu k objasnění hydratace komplexních přírodních systémů a to zejména přírodní organické hmoty.
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Added value of green roofs
Hrachovina, Vojtěch ; Žák,, Antonín (referee) ; Petříček, Tomáš (advisor)
Introduction is focused on analyze green roof like a part of buiding construction, when thesis assembly principles of right proposal green roof layers. Main part describes characteristic properties green roofs at global impact. We get some added values after comparison with classic roof types. Master thesis consists of survey of added values of green roofs in these categories: life cycle assessment, microclima, outdoor climate, water retention. End of thesis devote to psychological effect of green roofs include questionnare about relationship between czech society and green roofs.
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A Computer Game to Fight Drought in the Countryside in Unity
Petrjanoš, Dominik ; Milet, Tomáš (referee) ; Beran, Vítězslav (advisor)
The aim of this bachelor's thesis is a design and implementation of an entertaining and educational computer game. It is a simplified view of the complex issue of climate change. Nowadays we are surrounded by technology more than ever and the idea of bringing the issue of water retention in the landscape to the general public is proposed. The game consists of a map that is divided into game fields of different types and the user can take actions on them that lead to an increase in water retention. During the game the user learns more information about this issue. The Unity game engine was chosen for the implementation. The game object models were created in Blender.
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Water retention capacity of humic substances
Cihlář, Zdeněk ; Šmejkalová, Daniela (referee) ; Kučerík, Jiří (advisor)
Humic acids were extracted from South Moravian lignit. That humic sample was oxidized by either H2O2 or HNO3. In next step, oxidized humic acids were polymerized by formaldehyde in order to obtain cross-linked structures with improved water retention capacity. Affinity to water and water retention capacity of obtained products were studied by thermal analysis (DSC – differential scanning calorimetry and TGA – thermogravimetric analysis). In order to study above-mentioned parameters two different methods were used. First approach represented sorption of water to humic acids from three controlled humidities, for description of those processes TGA measurement was used. Second study was based on the DSC monitoring of water excess sorption. Results obtained from TGA measurements showed an increasing sorption ability with increasing relative humidity of the environment. DSC measurerents in hermetically sealed containers resulted in an increasing content of water bound by humic acids structures. All the modified samples of humic acids (oxidized as well as oxidized and modified by formaldehyde) gave higher retention capacity in comparion with the parental humic sample.
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Possibilities of using recycled materials for the green roofs constructions
Skalková, Markéta ; Žák, Antonín (referee) ; Žižková, Nikol (advisor)
This bachelor thesis deals with the issue of using recycled building materials in the green roofs. It studies the history, function, benefits and negative impacts, composition, division and structural layers of green roofs. The work describes the production, application and common features of recycled building materials. It determines the basic properties of selected recyclates and evaluates their partial suitability as some of the layers of a green roof.
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Effect of cellulose ethers on properties of hydraulic lime
Skoupil, Jakub ; Rovnaníková, Pavla (referee) ; Vyšvařil, Martin (advisor)
This diploma thesis deals with the study of the influence of cellulose ethers on the properties of hydraulic lime mortars. The availability and price of cellulose ethers in the industrial market is very favorable, but we can´t meet with studies using cellulose ethers in building materials, where lime is used as a binder. Cellulose ethers are commonly used as thickening agents in cement-based materials. The purpose of this diploma thesis is to review if cellulose ethers are appropriate for use in hydraulic lime mortars, either as water retention agents that contribute by water retention to better hydration of hydraulic binder components or to affect the properties of mortar in the fresh state. The theoretical part is dedicated to cellulose ethers, especially their production and how they influence the properties of building materials. In the practical part, the thesis deals with the influence of the dose of five different types of cellulose ethers on the properties of hydraulic lime. The properties in the fresh state and the physical-mechanical properties of mortars were monitored over time.
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Water analysis and combating drought in the Rokytná river basin
Říha, Tomáš ; Vrba, Jan (referee) ; Veselý, Jaroslav (advisor)
This diploma thesis focuses on water management analysis of the Rokytná River and finding suitable precautions usable by municipalities when dealing with drought and lack of water in their administrative district. The short research at the beginning of the thesis summarizes problematic of drought and lack of water in the Czech Republic, including the current state and overall context. Next part focuses on the assessment of current state of the Rokytná River basin, based on performed reconnaissance of the basin and processed analysis of a part of the basin delimited from km 0,0 to km 16,7 of the river, between towns of Ivančice and Moravský Krumlov. This analysis concentrates on finding factors, which can contribute to extent of drought impact in this area. It also contains a suspended load study of the waterway, which writes up granularity characteristics and calculation of the amount of transported material from a suspended load sample, taken from the bed of the Rokytná River. The overview of suitable proceedings and precautions follows, based on findings in previous parts of the diploma thesis. The conclusion of this thesis consists of very suggestion of suitable steps and precautions related to particular localities in the Rokytná River basin. Target is to enhance the retention ability of the region and to minimize the impact of both drought and floods. The result of these actions should be the empowerment of environmental sustainability in this particular area. Conclusions of this thesis can be used by municipalities and other administrative bodies when creating an approach of combating drought and when deciding about the implementation of relevant precautions.
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Studie možností zvýšení retence vody v povodí toku Červenka
Valchářová, Pavlína
The diploma thesis deals with the possibilities of increasing water retention in the Červenka stream basin. The literary research describes the issue of water in the forest landscape, what all has an effect on runoff and what are the ways to improve the retention capacity of the landscape. Furthermore, the natural conditions of the location are analyzed - geomorphology, geology and pedology, climate, hydrology, vegetation and fauna, and anthropogenic influences. On the basis of a field investigation, the current state of the water course, including all objects, is described. The forest road network and forest stands are evaluated. The study is based both on the informational characteristics of the area and on field research. The created design with the possibilities of water retention in the Červenka stream focuses on increasing the waterlogged site as a potential place for building ponds. But also on the forest road network, where the risk of water erosion is high and it is necessary to learn how to manage water better
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Water retention in the Úhlavka catchment area
Lukášová, Karolína ; Janský, Bohumír (advisor) ; Matějček, Tomáš (referee)
Water retention in the landscape is a very current topic these days. Thanks to a warming climate, we have to deal with hydrological extremes, erosion, or accelerated water runoff. If we choose to improve the retention capacity of the landscape, we can help transform flood waves, slow down runoff, and mitigate soil water erosion. In the agricultural landscape, we solve the mentioned problems by combining near natural measures and technical measures. This master thesis focuses on water retention in the Úhlavka basin, which is located in western Bohemia and forms a tributary of the Mže River. In the theoretical part, the physical-geographic properties of the area of interest and the rainfall-runoff process are characterized. A literature research is also carried out regarding retention, its components, and the factors influencing it. Furthermore, the individual types of measures that can be used to improve the state of retention in the landscape are also listed. The practical part offers a process of choosing a specific area for proposals in the Úhlavka basin. The Olešná basin was chosen, where the majority of the land cover is agricultural and, thanks to its geomorphological properties, it was also included in the list of critical areas. Three grassed strips, a swale, and strips of crops rotation...
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Vliv vodních nádrží v povodí na odtokové charakteristiky při srážko-odtokových událostech
HOŘEJŠÍ, Štěpán
This bachelor thesis, written as literary research, is focused on one of the most im-portant functions of water reservoirs - water retention. The aim of this bachelor thesis is to show the way water bodies are able to affect the hydrograph during rain-fall-runoff events. The first part of the thesis is focused on water categorization and the hydrological cycle. The next part comprises a detailed description of water res-ervoirs. This includes a list of their key functions and specific types. The history of water reservoirs is also mentioned. The third part is reserved for rainfall-runoff events. Finally, factors affecting water runoff are discussed, followed by an expla-nation of how water bodies affect water regimes. In the end, the influence of water reservoirs on the size and shape of the hydrograph during rainfall-runoff events is described.
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