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Optical determination of the state of charge of vanadium flow battery cells
Šacl, Vojtěch ; Chladil, Ladislav (referee) ; Novák, Vítězslav (advisor)
The investigated subject for this diploma thesis is getting know properties of the vanadium redox battery (VRB), especially electrolyte. Specialization is applied to the state of charge of this cell and its measurements using the optical methods. Upon different state of charge is changed oxidation number of vanadium and resultant color of the electrolyte. Using spectrofotometry method that characteristic property is undergone measurement. The basic thing was learning to handle a measurement system. The first practical measurement was executed on example foils. Upon measurement of vanadium cell there was obtained the values of absorbation, which they were used for determination of state of charge.
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Determination of selected chemical parameters of fruit of new currant varieties
Pelikánová, Blanka ; Diviš, Pavel (referee) ; Vespalcová, Milena (advisor)
Presented diploma thesis is dedicated to the determination of selected chemical parameters of fruits of new currant varieties. The theoretical part is focused on the characteristics of currant, the biologically active substances of its fruits and also the utilization of current in the food industry. Further part of the theory deals with the main chemical parameters which were examined: polyphenols, anthocyanins, ascorbic acid and antioxidant activity. In the practical part there were determined selected chemical parameters in six white, twelve red and thirteen black varieties of currant. Anthocyanins and polyphenols have been determined spectrophotometrically. The content of ascorbic acid in selected varieties of currant was determined by HPLC. As a technique for the determinationof the antioxidant activity was selected the method of free radical DPPH.
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Monitoring of the contents of phosphorus and nitrogen in wastewater
Herka, Milan ; Repková, Martina (referee) ; Vávrová, Milada (advisor)
This master´s thesis is focused on the occurrence of phosphorus and nitrogen in effluents and methods of their determination. In the theoretical part of the thesis describes methods for the determination of nitrogen and phosphorus in waste waters, their selection and optimization methods including mobile analytics. Experimental section is devoted to the abstraction of wastewater from selected wastewater treatment plants and their analysis methods including mobile analytics and comparing them with the presentation of their results. The conclusion is drawn evaluate the content of nitrogen and phosphorus in wastewater influent and effluent from wastewater treatment plants and compared the variation of these values during the one-month study and compared with published data.
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The measurement of total alkaloids in tobacco
Pipková, Renata ; Vránová, Dana (referee) ; Omelková, Jiřina (advisor)
The aim of this diploma thesis is the assay of total alkaloids in different tobacco types. To measure the content of total alkaloids are utilized types of tobacco used for preparation of tobacco blends and consecutive production of cigarettes. The samples of analyzed tobacco include various countries of cultivation and different crop years. There is described tobacco as a plant, in it contained alkaloids and the utilization of tobacco in the theoretical part. In more detail it deals with the production and construction of cigarettes which is closely related to the content monitoring of total alkaloids in tobacco. The contents of total alkaloids are determined by the continuous flow analyzer- SKALAR. On this spectrophotometer are set the contens of reducing sugars as well. The comparison of total alkaloids contents and reducing sugars from the perspective of single tobacco types, countries of cultivation and crop years is clearly summarized in the experimental part of the thesis that was performed in the company Philip Morris ČR, a.s.
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Determination of surfactants in waste waters
Švec, Pavel ; Čáslavský, Josef (referee) ; Vávrová, Milada (advisor)
Surfactants belong to surface-active compounds that have ability to restrain the surface tension; this ability is exploited to eliminate impurities. This study is focused on determination of surfactants in waste water to which these compounds can be transported from various cleaning and washing articles. In theoretical part are listed basic classifications of surfactants, their properties and requests of Czech legislative for their content in waste water. Furthermore here are described chosen analytical procedures for determination of anion-active, cation-active and non-ionic surfactants in waste water. The conclusion of the work is evaluation of measured results of surfactants concentration in inflow and outflow of waste water from waste-treatment plant in University of Veterinary and Pharmaceutical Sciences Brno and waste water from neutralizating station in FCH BUT. To determination of anionic surfactants were used two methods, arbitration method with usage of methylene blue and mobile analytics method which is based on chemical reaction between target compound and chemical agent. This reaction leads to formation of coloured compound able to spectrofotometric determination.
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Issues of boron in water
Šípková, Helena ; Nevrlá, Jana (referee) ; Komendová, Renata (advisor)
This bachelor thesis is focused on boron and its compounds. It is dedicated to properties, sources and the use of these substances and their effects on living organisms. The emphasis is put on the issue of boron in water. In this work are possible forms of this element in water, legislative rules and regulations and methods of its determination described. The experimental part is focused on azomethine-H spectrophotometric analysis to identify the stability of boron samples and their possible preservation.
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The occurence of Cadmium in environment
Bělohlávková Staffová, Petra ; Řezáčová, Veronika (referee) ; Sommer, Lumír (advisor)
Heavy metals, including cadmium, belong to the contaminants of the environment. With permanently increasing pollution, there is an increase of these metals in the water, in the air and in the soil, which are involved in the food chain and subsequently the food of human. Cadmium has received considerable attention for its toxicological properties. Similarly, monitoring of cadmium in the Czech Republic is relatively large. There is a legislative measure regarding not only the permitted level of cadmium in the air, in the water, in the soil, but also food and is also restricted its use in the industry. Further they developed methods of its determination. In this work was devoted to attention photometric determination and some electroanalytical methods, then spectrometric methods mainly atomic absorption spectrometry and atomic emission spectrometry, which is currently the most widely used.
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Study of ozone decomposition on solid surfaces
Krejsková, Eliška ; Stančík, Jiří (referee) ; Kozáková, Zdenka (advisor)
This bachelor’s thesis is focused on the study of ozone decomposition which occurs during its contact with solid surfaces. The aim is to find out which material causes the lowest ozone decomposition and that is why it is the most suitable material for pipelines used for ozone transportation from a place of production to a place of application. In the theoretical part important properties of ozone, possibilities of its production, methods of ozone determination and relation of ozone to different solid surfaces were described. In the experimental part there was investigated how much ozone is decomposed by five commonly available metal materials (stainless steel, yellow brass, copper, aluminium and iron). Measurements were realized in the glass tube (Liebig condenser). Hollow pipes made of particular material were inserted into this tube. Ozone passed through this glass tube and ozone concentration was determined on its output by two methods: the iodometric titration and spectrophotometry. Several series were measured and compared by different set-up conditions like reaction time, experimental parameters (flow rate of air, input power of the ozone generator) and two types of gas – technical and synthetic air (because moisture contained in technical air can cause ozone decomposition) were used. The most suitable materials – stainless steel and aluminium were determined according to gained results.
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