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Thermodynamics of Solutions
Macháč, Pavel ; Münsterová, Eva (referee) ; Molliková, Eva (advisor)
This bachelor thesis deals with principles of thermodynamics of solutions. The theoretical part is initially concerned with question of solutions generally, such as for example the issue of classification of solutions, expression of solutions composition and a range of mutual solubility. The pivotal part of this document deals with solid solutions, mainly from the thermodynamic point of view. Specifically the issue of thermodynamic activity of components in these solutions is highlighted. There is a detailed description of the ways of determination of the thermodynamic activity, both experimentally and through the use of calculation. Finally there are described the possibilities of the use of the thermodynamic activity, such as for example using it to calculate the other thermodynamic quantities. The practical part of this thesis includes calculation of the thermodynamic activity of components of alloy Bi-Mg at assigned temperature, the partial molar dissolving free enthalpy of components in solution and the calculation of total dissolving free enthalpy of the solution.
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Modification of material production flow of the sewing machine needles
Změlík, Josef ; Macháč, Patrik (referee) ; Kašpárek, Jaroslav (advisor)
Main focus of this diploma thesis is the analysis and subsequent modification of production flow at a company, which is one of the world’s leading providers of industrial needles, precision parts and fine tools. Practical part of this thesis is devoted to the current flow of values and consequently describes its individual modifications. In this part the production areas are mapped, and the material handling system is described. This part also suggests a possible layout modification at the production site and simulation of proposed changes in Plant Simulation software from Siemens PLM Software. At the end of the work there are changes described that relate mainly to the philosophy 5S, kanban system or ergonomics of the workplace.
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The study of the influence of process parameters on the roughness of the cut for flame laser cutting of structural carbon steel
Macháč, Patrik ; Hála, Michal (referee) ; Mrňa, Libor (advisor)
This bachelor thesis deals with the cutting of material with laser in an oxidizing environment. It is divided into two parts, theoretical and practical. The theoretical part describes general methods for cutting materials, their advantages and disadvantages, further current industrial lasers are described, as well as the influence of parameters on cutting quality. In the experimental part has been processed the influence of process parameters on the quality of the cut and comparison with ISO 9013. Material used in the practical part is the structural carbon steel called S235JRG2, which was cut in the oxidizing environment. Based on the evaluation of surface, the price of lasser cutting of one meter was selected and then as th best option of settings process parameters for achieving good surface quality was selected. At the conclusions of the thesis there are compared changes in proces parameters and their evaluation
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High resolution digital light source design for automotive industry
Machač, Petr ; Rubeš, Ondřej (referee) ; Věchet, Stanislav (advisor)
Digital high definition light sources are a new way of communication between car and other road users. By intelligent switching of high beam or projection of various warning or information symbols on the road a lot of even tragic traffic accidents can be prevented. The purpose of this thesis is to explore contemporary automotive lighting technologies, then to choose the appropriate technology for high definition light source and design a prototype of mechatronic lighting systém.
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Design of autonomous vehicle simulator
Machač, Petr ; Králík, Jan (referee) ; Věchet, Stanislav (advisor)
Tato práce se zabývá simulačními prostředky pro vývoj algoritmů pro řízení autonomních automobilů. V zásadě lze rozdělit na dvě části, na rešeršní, teoretickou, a praktickou, vývojovou. V té prvně zmíněné je uveden přehled dostupných nástrojů pro simulaci autonomních vozidel, jedná se jak o nástroje open-sourcové tak placené. Dále se v teoretické části popisuje princip a nástroje, resp. enginy pro řešení dynamických rovnic na počítači. Důraz je kladen na fyzikální engine Box2D který je dle zadání této práce využit ve druhé části teze pro vývoj vlastního prostředí simulujícího autonomní automobil.
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Absence
Machač, Petr ; Marenčík, Michal (referee) ; Zet, Martin (advisor)
Video Absence reflects the findings of theoretical thesis named Boredom. The basic situation is described as lack of meaning, will, interest and feeling. Video is an attempt at poetic reflection of such situation, which is characterised as aimless searching without finding. The main tools are empty hands and different kinds of ground. The void has been overcome through the gesture related to problem of gift.
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Passivation of Aluminum and Aluminum Alloys in passivation baths without Cr6+ Compounds
Macháč, Pavel ; Tulka,, Jaromír (referee) ; Molliková, Eva (advisor)
This diploma thesis deals with evaluation of efficiency of protection conversion coatings created by passivation metals and alloys in passivation baths without chromium compounds. The theoretical part is initially concerned with question of electrochemical corrosion of metals, consequently there are mentioned different methods of corrosion protection. The main section of theoretical part of this thesis deals with chromate conversion coatings, description of their protective efficiency (including their unique self-healing effect) and then with account of new chromate-free conversion coatings occurring as chromate alternatives, whose usage is constrained because of their content of hexavalent chromium, which is highly toxic, oxidizing and also carcinogenic and thereby very dangerous for human body and the environment. Experimental part of this thesis is concerned with evaluation of efficiency of particular conversion coating which is quite commonly use in some applications as chromate alternative. It is chromate-free conversion coating which is created by passivation of metals or alloys in passivation bath Pragokor BP, which contains zirconium fluorocomplexes and is without any chromium or other toxic or ecologically unhealthy compounds. The influence of sealing of the coating in preparation Pragokor Seal Al and also other surface treatments such as application of conservation wax WAXENG or cold application of zinc coating were tested too. Efficiency of mentioned surface treatments was then evaluated on aluminum and steel by laboratory accelerated and atmospheric corrosion testing.
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Calculation of the network steady state on the voltage level 110 kV
Macháč, Petr ; Vaculík, Petr (referee) ; Mastný, Petr (advisor)
This thesis deals with load flow calculation of electrical network 110 kV before and after the connection to the 70MW gas supply and the 58MW steam and gas supply. This grid can be powered from two 400/110kV substations, namely Sokolnice and Otrokovice. The load flow calculation is realized for the power supply either from Otrokovice or Sokolnice. Furthermore, the calculation of the uni-phase and three phase short circuits in the substations of 110kV network is realized in this thesis. The result of the thesis is the assessment of the voltage ratio in the network, current load of the power line and short circuit resistance of the substations.
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Temporal features of Czech fricatives
Homolková, Veronika ; Machač, Pavel (advisor) ; Skarnitzl, Radek (referee)
The thesis is focused on a description of temporal features of Czech central fricatives (f, v, s, z, š, ž, ch [x], h). The duration of fricatives in the intervocalic position is investigated according to the place of articulation and the voicing contrast. These results are contrasted to the preceding comparable researches. Also other contexts that can influence the duration of fricatives are examined (the phonological quantity of the neighbouring vowels, the position of the fricative in the stress unit, the type of speech, the gender of the speaker). The possible reciprocal influences are analysed in relation to the duration of the fricative and the articulation rate. The thesis deals also with the compensation tendencies in the field of duration of sequences "vowel + fricative" or "fricative + vowel". The basis for this research is formed by adequately extensive material of two types - read speeches, acquired advisedly for this analysis, and semi-spontaneous speeches, gained thanks to the Prague Phonetic Corpus (formerly Phonetic-Acoustic Database of Czech), created at the Phonetic Department of the Faculty of Philosophy and Arts, Charles University in Prague. The methodical basis for the thesis is formed by the doctoral thesis of PhDr. Pavel Machač, Ph.D.
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