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Evaluation of water vapour permeability
Zemánek, Petr ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
The theme of this work is the knowledge of technical terminology and the laws of physics permeability materials in various industries. There are described basic properties of water vapor permeability and their meaning. This work refers to the possibility of measuring permeability in different application areas. The practical part involves the measurement and evaluation of water vapor transmission on selected samples.
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Transport of humic substances into leafs
Žáková, Michaela ; Kalina, Michal (referee) ; Klučáková, Martina (advisor)
This bachelor thesis simulates leaf foliar fertilization and describes transport processes of humic substances. Experiments were performed for two areas. The first focused on the flow through the plant cuticle as the main selective barrier. In the second one the transport of humic substances to the leaf was studied. The diffusion process was evaluated by the concentration loss of lignohumate solutions, which served as the medium of humic substances in the solution - leaf model. The results showed the effect of cuticle on nutrient penetration and its dependence on its condition. New findings are the transfer processes of humic substances into the leaves, that have proved effective in a short period of time, mainly at higher concentrations.
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Transport of drugs in humic hydrogels
Shalabodova, Kseniia ; Krouská, Jitka (referee) ; Klučáková, Martina (advisor)
Presented bachelor’s thesis focuses on the study of diffusion of drug in humic hydrogels. The aim of the work was to appraise the effect of the presence of the humic substances in the transport capacity of the diffusing compound. The main idea of experimental part was to compare the drug’s transport in samples of humic acid gels with the transport in agarose hydrogels samples. For this study diffusion couple method was used which was based on monitoring the development of diffusion profiles of drug in gels with the passage of time. As a diffusing medium sulfapyridine belonging to sulfonamide antibiotics class was used.
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Transport of metal ions in humic hydrogels
Hegr, Martin ; Smilek, Jiří (referee) ; Klučáková, Martina (advisor)
This diploma thesis is focused on the study of diffusion of metal ions in hydrogel of humic acid. The objective of this thesis was to investigate the effect of the concentration of metal ions supply source and duration of diffusion on transport through the gel using method of diffusion couple. Cupric, nickel and cobalt ions were esed like the diffusion medium. All these ions were selected thanks to their high affinity for the humic acids and because they are ideal to investigate the diffusion through the humic gel. Chloride salts of these metals, namely CuCl2, NiCl2 and CoCl2, were used like supply sources. Three different concentrations of each solution were compared, specifically 0,05M, 0,1M and 1M, and also were three different durations of diffusion, specifically 10 hours, 1 day and 3 days. Metal ions were compared with each other in order to determine which one has the best transport properties through the humic hydrogel. The data, necessary for calculation, were obtained by UV-VIS spectrophotometry. Diffusion coefficients and duffusive flux of individual metal ions were determined from measured data.
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Study on reactivity of humic acids via method of diffusion cells
Hrubá, Pavla ; Weidlich,, Tomáš (referee) ; Sedláček, Petr (advisor)
The diploma thesis focuses on utilization of diffusion cells in reactivity mapping study on humic acids. In the experimental part, samples 6 humic acids of different origin or chemical modification were studied. All the samples were characterized by basic analytical and physico-chemical methods (elemental analysis, thermogravimetry, determination of acidity, spectrometry). Methylene blue was utilized as a model reactive probe and agarose gel as an inert support medium. An effect of interactions between humic acids and methylene blue on diffusivity of the dye in the hydrogel was determined and discussed.
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Destratification of Reservoirs
Sluše, Jan ; Kozubková, Milada (referee) ; Šulc, Jan (referee) ; Pochylý, František (advisor)
This doctoral thesis is focused on design of new equipment for aeration of water surface with low depth of water column. Aeration is one of ecological preventive methods to prevent growth of cyanobacteria. Increase of dissolved oxygen content in water mass leads to support of the growth of organisms which are disadvantaged by impossibility of movement in water mass and thus also to support biodiversity. Given biodiversity has a positive effect on water quality because it avoids the outbreak of one species of aquatic organism, in particular of cyanobacteria. Designed aeration equipment uses membrane formed by hollow fibre to transport oxygen into the water. When aeration dissolution of oxygen occurs directly on the membrane surface which prevents air leak in the form of bubbles. This type of aeration has low operating costs and high efficiency of input of the oxygen into the water. Distribution in the aquatic environment is ensured by special boat. This boat is moving on the water surface and the technology is installed on the upper deck. The aeration is carried out by an aeration module situated in the water. The movement of the boat is partially ensured by autonomous control.
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Analysis of substances released from composite dental material
Fučík, Jan ; Řezáčová, Veronika (referee) ; Mravcová, Ludmila (advisor)
This master's thesis deals with a present problem of alternative dental fillings, which should replace amalgam fillings. Although there are health concerns about these alternative materials, especially resin composite fillings raise concerns, because they release potentionally harmful substances into the oral cavity. Accordingly even this medical device subjects various tests before releasing to the commercial market and one of these tests was carried out according to ČSN EN ISO 10993 and available scientific literature in the experimental part of this thesis. The amalgam controversy, substances used for manufacturing of resin dental fillings and analytical methods are described in the theoretical part of the thesis. In the experimental part of the thesis, 30 days long cumulative extraction experiments were carried out into various extraction mediums in order to assess suitability of new dental resin filling from ADM, a.s. by comparison with commercially available dental material from company GC EUROPE N.V. These samples were analysed by LC-MS and the amount of eluted substances from dental composites to extraction medium was quantified.
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Computer modeling of MOSFET transistor
Major, Jan ; Harwot, Ondřej (referee) ; Pokorný, Michal (advisor)
Work is focused on computer modeling of PN junction and MOSFET transistor in the program COMSOL Multiphysics and in program TiberCAD. The text is discussed on the drift and diffusion in semiconductors. Also shown is a method of modeling the PN junction and MOSFET transistor in the programs and compare models.
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Diffusivity of humic hydrogels
Král, Jan ; Smilek, Jiří (referee) ; Klučáková, Martina (advisor)
Presented diploma thesis focuses on the study of diffusion of cupric ions in humic acid gels. A total of fifth different standards of humic acids and one sample humic acid prepared from same source as in bachelor's thesis, on which this thesis continues, were used for preparation solutions of humic acids. Thereafter, these solutions were used for preparation of agarose hydrogels, which were necessary in following diffusion experiments. The objective of the work was to compare transport properties of humic standards between themselves and then compare standards with humic acid prepared from same source as in bachelor's thesis. Measure, which was used to determine the transport properties, was comparison of effective diffusion coefficients. Method of instantaneous planar source diffusion was used to compare them. This method was based monitoring temporal evolution of diffusion profiles of cupric ions in humic hydrogels. Copper ions were selected as diffusing medium because of their high affinity and strong bonds to humic acids.
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Study of interactions of pigments with biopolymer chitosan
Kolesa, Pavel ; Kalina, Michal (referee) ; Klučáková, Martina (advisor)
This master's thesis was focused on the study of interaction of some organic azo dyes (model diffusion probes) with cationic biopolymer chitosan. This interactions were realized via diffusion processes in hydrogel media based on thermoreversible agarose. The main aim was study of influence of pH of solution on the diffusion process. Interactions of used dyes are based on electrostatic character. The aminogroup of chitosan interacts with the functional group of chosen dyes (anionic sulfonic group) and thus affects the process of diffusion. The model diffusion compounds were chosen organic anionic dyes Chicago sky blue 6B (C.I. 24 410), Sirius red (C.I. 35 780) and Reactive blue 49 (C.I. 621 526). The important content of this diffusion method is a monitoring of the time progression of diffusion profile by UV-VIS spectrophotometry. The presented work follows the bachelor thesis and shows comprehensive view of the reactivity of chitosan and its behavior in different systems. Unsteady diffusion in cuvettes appears to be a universal method for the study of reactivity of biopolymers and for the study of transport processes in hydrogel media. The diffusion method is universal, easy and cheap.
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