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A COMPARATIVE STUDY OF LIQUID- AND GAS-PHASE CYCLOPENTENE HYDRATION CATALYZED BY THE MCM-22 ZEOLITE
Krupka, J. ; Otmar, J. ; Pawlesa, Justyna
The study deals with technological aspects of the direct hydration of cyclopentene to cyclopentanol. The catalytic properties of the MCM 22 zeolite were studied in the case of cyclopentene hydration both in liquid and gas phases. MCM-22, unlike other solid acid catalysts, is highly selective for the formation of cyclopentanol in the liquid-phase hydration in the slurry arrangement. It suppresses completely the undesirable etherification of cyclopentanol and allows obtaining cyclopentanol with almost 99% selectivity. But the liquid-phase hydration was found to lead to rapid deactivation of the zeolite. The deactivation is caused mainly by a formation of carbon deposits in the pores of the zeolite. When hydrating in the gas phase on the fixed bed of granular catalyst, it could be easy to periodically reactivate the catalyst in situ. However, it has been found that the exceptional selectivity of MCM-22 to the cyclopentanol formation is characteristic only for the liquid-phase hydration. The reaction in the gas phase is unselective. Furthermore, the equilibrium conversion of cyclopentene to cyclopentanol in the gas-phase hydration has been found to be industrially unusable below 1 % (e.g. under atm. pressure, at 120 degrees C and with a molar ratio of cyclopentene to water 1: 5, it is as low as 0.3 %).
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Modification of the test rig for the testing the bearings for the space applications
Okál, Michal ; Křupka, Jiří (referee) ; Košťál, David (advisor)
This bachelor thesis deals with the design of a device, which allows exploration of rolling bearings properties in space conditions. The adjustment is necessary for testing of a new rolling bearing with different dimensions. Preload of the bearing must be centered and adapted for rapid heat exchange with the surroundings. The effort is made to use maximum number of existing components and torsion stiffness of the device. The thesis outputs are the accompanying report and the technical documentation allowing the production of new components.
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Development of ventilating turbines
Křupka, Jiří ; Malach, František (referee) ; Malášek, Jiří (advisor)
This Master thesis solves a construction development of alternative modular mechanical systems for ventilation turbines. A research part of the thesis deals with the issues of transported medium (air) and ventilation, as well as functions, designs of ventilation turbines, and finally it provides an overview of ventilation turbines produced by manufacturers worldwide; these are used for ventilation of residential, commercial, industrial or agricultural structures using the natural or hybrid ventilation. A construction - design part is focused on creating 3D models of selected alternative modular adjustable ventilation turbines according to the data provided by the thesis supervisor and then on establishing a system for calculating the shapes of blades relative to the airflow for additional axial fan of ventilation turbines. For this purpose, a customized software application VENTILATOR (GUI) was developed to allow a flexible change of input calculation parameters and thus a fast modification of the curve shape in the 3D model of the axial fan blade.
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The issue of pre-contractual liability in relation to the practice of negotiating and concluding commercial contracts under national law and case-law of selected EU countries
Krupka, Jiří ; Horáček, Vít (advisor) ; Eichlerová, Kateřina (referee)
The thesis deals with questions of pre-contractual liability which is seen as a very specific institute whose conception is diverse in different EU countries and also outside. The main research question is a difference between pre-contractual liability perception in the different countries and its full description in relation to the negotiations of business contracts with an emphasis on Czech law. In the first part, the author analyses historical background of pre-contractual liability in relation to Roman law and German-Austrian legal systems in which the professor Jhering developed that construction of culpa in contrahendo. In the following chapters, the author deals with the description and nature of pre-contractual liability, particularly in questions of whether they are contractual or delictual liability and enter into details the basic facts, example and extent of damages with respect to the European concept of pre-contractual liability. He concludes that the pre-contractual liability is in the European concept as delictual liability, with regard to the decision of European Court of Justice. The author simultaneously mentions that although similar facts in the legal systems, the extent of damages is very different when there is a clear dichotomy between positive and negative interesse. The...
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Magnetic separator
Křupka, Jiří ; Jonák, Martin (referee) ; Malášek, Jiří (advisor)
The aim of this bachelor thesis is to design the structural conception of magnetic separator designated to separate small-sized industrial waste. This report provides an overview of facilities of worldwide manufacturers that are used for magnetic separation of steel scrap. Furthermore, it offers an assessment of variants for technical solutions to structural nodes of magnetic separator; this is followed by a selection of specific solution. According to the input parameters, all the parameters necessary for correct machine design are computed. These computations also include the justification of selected table values, placement, surface roughness, geometric tolerances, materials and heat treatment of the individual parts and assemblies. Attachments to this technical report are documentation drawings of selected parts and assemblies.
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