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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Využití bezmembránové elektrolytické cely pro elektrochemické generování těkavých specií přechodných kovů / Application of non-membrane electrolytic cell for electrochemical volatile species generation of transition metals

Kobrlová, Andrea January 2013 (has links)
This diploma thesis is focused on the study of electrochemical generation volatile species of gold and silver. Two non-membrane electrolytic cells were constructed for electrochemical generation volatile species. These cells differ in the volume of electrode chamber. An atomic absorption spectrometry with quartz tube atomizer was used in most experiments. The equipment was performed in flow continuous mode. Experiments confirmed, that it is possible to use an atomic absorption spectrometry with quartz tube atomizer for generate volatile species of gold and silver by using two non-membrane electrolytic cells. The main part of this thesis was to find optimal conditions for the electrochemical generation of volatile species of gold and silver. These optimized parameters were: the cathode material, the type of electrolyte, the flow rate of the carrier gas, the generation current and the electrolyte flow rate. The calibration curves for both analytes were measured for both non-membrane electrolytic cells and the basic characteristics of the measurement were observed. Detection limit for electrochemical generation of gold was 1,61mg dm 3 and repeatability 3,93 %, detection limit for electrochemical generation of silver was 0,20 mg dm 3 and repeatability 7,33 %. Thanks to the experiments with a...
42

Charakterizace a analytické využití pyridinoporfyrazinátu kobaltu jako neplatinového mediátoru v elektrokatalýze vodíku / Characterization and Analytical Application of Cobalt Pyridinoporfyrazinate as a Non-Platinum Mediator in Hydrogen Electrocatalysis

Klusáčková, Monika January 2019 (has links)
This work reports on the cobalt pyridinoporphyrazinate (CoTmtppa) as a platinum-group metal-free catalyst for hydrogen evolution and oxidation reactions with the possibility of use in hydrogen energy and hydrogen potentiometric sensing. A different interaction of CoTmtppa with various electrode substrates, highly oriented pyrolytic graphite (HOPG) and annealed gold (Au(111)), affects its electrocatalytic behaviour in hydrogen reactions. The formation of a hydride-type complex with the bonding of hydrogen atoms to cobalt centre is supposed to be the rate-determining step. In the case of hydrogen evolution, the maximum catalytic activity of mediator was reached at pH = 11,0, when the HOPG/CoTmtppa showed overpotential decrease by 300 mV and an almost 60-fold increase of current densities compared to HOPG. The electrocatalytic activity of Au(111)/CoTmtppa resulted in a further decrease of overpotential by 175 mV in comparison with HOPG/Co(I)Tmtppa. The electrochemical oxidation of hydrogen was found to depend on hydrogen source which was electrochemically generated on-site or molecular hydrogen supplied from an external source. In the case of electrochemically generated hydrogen, the maximum activity of HOPG/CoTmtppa was reached at pH = 2.1 and an additional it was observed 50 % increase in current...
43

ResPublica/Civitas Socialis – Strachotín, l. p. 2017 / ResPublica/Civitas Socialis - Strachotín

Sysel, Tomáš January 2017 (has links)
The theme of the development of the existing sports grounds was dealt with Based on a number of analyzes, visits to the site and communication with the community management, the theme of the development of the existing sports grounds was dealt with. The whole territory is up to a football field in a very maintained conditions. There are two smaller accommodation facilities, which are seasonally used mainly by schools in nature and other students, but their condition is quite unsatisfactory. The soccer field, which is the only one maintained, belongs to the existing base of soccer players - the dressing room with the clubhouse. Their condition is also somewhat aggravated. In the current spatial plan, the whole proposed area is at the interface of two areas, the first is the area of sport and individual recreation and the second is the area to be examined. Urban design is based on the location of the existing soccer field and the preservation or improvement of existing links to the surrounding area. Most of the paved areas will be overtaken. Part of the design of the development of sports activities in the village was also to find a possible solution for parking for tourists, for which there is no free space in the village. The chosen location is advantageous in that, when a parking lot will be created, it will be created near the main entrance to the village on road II. Cl. No. 420 from Hustopeče through the village. Architectonically, but also conceptually, the construction is based on the economic possibilities of the municipality, the possibilities of variability of the solution and especially of the possibilities of staging construction. The result are two buildings. One main, replacing the background of spccer players, creates the conditions for year-round training in the new gym, for going to fitness, while part of the building is a platform for the soccer field. The second building is an accommodation that replaces the existing unsatisfactory buildings. Architecturally, they are masses that are greatly affected by the modules. The building structure and the facilities of the sports hall are structurally designed from standardized modular systems, steel containers that are interconnected to create an unusual spectacle. The area of the gym is defined by a reinforced concrete skeleton. Both buildings are covered with gold anodized sheet metal, which is profiled similarly to the peripheral walls of the containers. At the same time, the object was to create year-round sports grounds that are accessible to the general public and youth.

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