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Application of superabsorbents in soil and its influence on plant growth
Závodská, Petra ; Kalina, Michal (referee) ; Klučáková, Martina (advisor)
This thesis is focused on description of superabsorbents with controlled released of nutrients, specifically macronutrients nitrogen, phosphorus and kalium. Superabsorbents are polymers, mostly acrylic acid polymers, that can absorb huge amount of water without dissolving in it. In its structure they can hold water and thanks to this they are very perspective materials for agricultural usage. Experimental part was focused on growing corn with use of superabsorbents and control samples without use of superabsorbents. Plants were growth for 3 time periods, specifically 46, 60 and 74 days. During the experiments, plats were growth without water stress and in controlled conditions in growing box under UV lamp that simulated day and night by turning on and off after 12 hours. At the end, an image analysis was performed in HARFA program, from which we got information about branching of the roots. Results were supplemented by soil and plants analysis.
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Preparation of magnetorheological fluids with high sedimentation stability
Oharek, Lukáš ; Kalina, Michal (referee) ; Smilek, Jiří (advisor)
The introduced bachelor thesis focuses on the current issue of stability of magnetorheological fluids in the gravitation field. To prepare stable magnetorheological fluid, influence of additives, particles modification and different carrier fluid are investigated. Regarding the increased viscosity of the carrier fluids, which negatively affect the magnetorheological effect, a magnetorheological fluid containing carbonyl iron particles, which were chemisorbed with non-ionic surfactant Tween 20 was prepared. Mineral oil and water emulsions were used as a carrier fluid, emulsifier Span 80 was used to stabilize the water-in-oil emulsion. Sedimentation stability is improved, at the same time the viscosity of the carrier fluid is increased.
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Influence of pH on Extraction of Matter from Biochar-Soil Complex
Jakubčeková, Kristína ; Enev, Vojtěch (referee) ; Kalina, Michal (advisor)
Biochar is one of the possible solutions to improve the soil fertility, therefore it is necessary to investigate both its composition and the impact on the soil under various conditions. The aim of this bachelor thesis is to focus on the description of the influence of pH on the amount and type of substances (molecules, ions) that are leached from the biochar into the soil and thus consequently influence its properties. As a soil model it was chosen cambisol which is the most widespread soil in the Czech Republic. The selected pH values have been defined in such a way to cover the pH range that is common for various soil types in natural conditions. In the experimental part of this thesis the extracts from the used sample of biochar and soil were characterized first. These characteristics obtained in this way were subsequently compared with the data obtained for the biochar-soil complex extracts that was obtained after a defined period of cultivation of the mixture. For the characterization of extracts the basic physico-chemical methods (pH, conductivity, elemental and thermogravimetric analysis, UV-VIS) and also the analysis of leached ions and molecules by means of ICP/OES, GC-MS were used. Evaluated experimental data show that under the condition of cultivation experiments, the influence of biochar was observed only on the basic physico-chemical characteristics of the soil (mainly pH). On the other hand, there was no significant tendency of the impact of biochar on the representation of selected elements and on the content of organic matter in the soil. Long-term biochar-soil cultivation experiments could be a suitable solution.
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Utilization of interfacial rheology to study of biological systems
Kachlířová, Helena ; Kalina, Michal (referee) ; Smilek, Jiří (advisor)
The aim of this bachalor thesis is to implement and optimization a relatively new method of interfacial rheology. The optimization of this method was realized on two types of interfaces, specifically liquid-liquid using immiscible systems water-chloroform and water-toluene, and water-air. The applicability of this method was tested by using real samples in form of surfactant septonex and biological system represented by protein (bovine serum albumin). The interfacial layers formed by septonex were purely viscous, where the rigidity of the layer increased slightly with concentration until reaching critical micellar concentration and then the rigidity decreased. In comparison with septonex, the interfacial film made of bovine serum albumin showed predominantly elastic behaviour.
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The Study of Biopolymers Stability Using Light Scattering Techniques
Kratochvíl, Zdeněk ; Sedláček, Petr (referee) ; Kalina, Michal (advisor)
The stability of chosen biopolymers (or simple carbohydrates and amino acids) was in-vestigated using light scattering methods. Samples were prepared by dissolving the sub-stance in deionised water or in diluted acetic acid. Firstly, the effect of increasing concen-tration on zeta potential was observed and the optimal concentration for the next measure-ments was determined. Afterwards, the stability and the molecular weight of used sub-stances were studied during long-time storage in different time intervals. It was found out that chitosan, CMC, hyaluronate and sodium alginate were subjected to degradation whereas increase of the molecular weight and the zeta potential was observed in case of BSA. In the end, the samples were exposed to several different external effects, namely the influence of different temperatures, UV radiation and increasing ionic strength. The results showed that rather higher temperature has a significant impact on biopolymers stability. However, used biopolymers were hardly affected by UV radiation except BSA whose molecular weight increased considerably. Decrease of the zeta potential absolute values and the molecular size usually occurred with increasing ionic strength. The change of molecular weight was not detected.
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Mobile robot control system
Kalina, Michal ; Veselý, Libor (referee) ; Hynčica, Ondřej (advisor)
This thesis deals with building of two-wheeled mobile robot and consecutive creation of drivers and control for sensors, engines and controller design. The control is based on Arduino platform using ATmega328 processor. Firstly there is in this thesis recherche. Part of this thesis is modelling one where simulation model of our system is created, its linearization and then controller design. Further it contains description of the building robots body, description and functionallity of used engines, description of all sensors and detailed description of available printed circuit board. In the end there is software part where the engines control is described, operation of the sensors and functionallity of the controller. Result of this thesis is function application of controlling and operating of two-wheeled unstable mobile robot.
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SEC-MALLS study on hyaluronan-albumin interactions
Sereda, Alena ; Kalina, Michal (referee) ; Chytil, Martin (advisor)
This work is focused on interactions of hyaluronan (HA) and bovine serum albumin (BSA). These interactions were studied by SEC-MALLS method, where molar mass, root mean square (rms) radii, hydronamic radius and intrinsic viscosity of particles of the system were defined. Additionally, interactions were examined by measurement of DLS and zeta potential, where hydrodynamic radius and a value of the zeta potential were defined. The interactions were confirmed at any of the used media, but with different efficiency. Furthermore it was found out, that the high ionic strength minimizes the range of the interactions, magnifies the radii of the complexes, their intrinsic viscosity and zeta potential. It was proved that complexes become smaller in their radii and viscosity with growing BSA concentraton.
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The utilization of atomic force microscopy for study on hydrogels
Lišková, Kateřina ; Kalina, Michal (referee) ; Smilek, Jiří (advisor)
The presented bachelor thesis deals with the study of atomic force microscopy (AFM), especially the optimization of the measuring procedure for imaging the surface of variously crosslinked hydrogels in the hydrated state. The most attention was given to the physically crosslinked polysaccharide hydrogel (termoreversible agarose) in hydrated state, where the surface of the samples with mass concentration of 4, 2, 1, 0,75 and 0,5 % was measured. Subsequently, the surface of the ionically crosslinked 2 % alginate gel with calcium ions was measured. Based on a literature research, measurements were performed in water using the method of quantitative imaging (QITM Advanced Imaging), which is especially suitable for soft samples with uneven surfaces. Multiple cantilever were tested for measurement, finally the SNL-10 cantilever was selected, which showed versatility for imaging samples in any measuring environment, especially aqueous. The pore sizes of the agarose hydrogels were monitored by image analysis ImageJ. For the measurement of hydrogels in the swollen state, the procedure of measuring their surface using atomic force microscopy has been optimized, but for different types of hydrogels, individual optimization of both preparation and instrument setup will be required.
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Transport processes in hydrogels
Sárová, Michaela ; Kalina, Michal (referee) ; Klučáková, Martina (advisor)
This master's thesis is focused on study of transport processes in hydrogels based on humic acids. For this purpose is used methods unsteady diffusion in cuvettes, which was studied the transport of organic dyes, specifically methylene blue and rhodamine 6G, in agarose hydrogel without the addition and with the addition of individual standards humic acids (Leonardite, Elliott Soil, Suwannee River II and Pahokee Peat). This method is based on spectrophotometric monitoring of concentration changes of dyes depending on space of the cuvette and on time. The aim of this thesis was to investigate the effects of interactions between diffusing dye and the particular type of gel to the resultant effective diffusion coefficient of dye. The experiments indicate that the presence of humic acid in the hydrogel greatly affects the transport of selected dyes.
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