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Induction Machine Operation Mode Type Effect Onto The Losses
Skalka, Miroslav ; Schreier, Luděk ; Janda, M. ; Ondrůšek, Č.
This paper deals with analysis of losses behavior of Induction Machine for both operation mode types (motor/generator). The purpose of this work is the definition of eqiuvalent circuit parameters and theirs non-linear behavior depending on various factors - slip, mechanical torque, temperature. In this paper would be presented behavior of iron losses and joule losses of rotor and stator with specific parameters behavior. The whole analysis is done in ANSYS (by FEM) and MATLAB program.
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Optimal production strategy of the chosen company in the area of mechanical engineering
Brachtlová, Veronika ; Průša, Přemysl (advisor) ; Všetečková, Dana (referee)
The topic of this diploma thesis is "Optimal production strategy of the chosen company in the area of mechanical engineering" - namely the EUTECH join stock company, or more precisely its toolshop division, which deals with the manufacture of injection moulds, parts and production of special devices for aircraft industry. The aim of the paper is to evaluate, according to the defined factors, what is for the EUTECH join stock company more favourable - invest in purchase of the 5-Axis CNC machining center technology and deal with this process inside of the company or ensure this technology in cooperation with another companies. The thesis is divided into two main parts - theoretical and practical. In the theoretical part, the subjects of operation management theory and production are dealt with. The practical part deals with the production strategy of the EUTECH join stock company, or more precisely of its toolshop division in detail. The company is briefly introduced, the situational analysis of division toolshop is conducted and the production process of the company is examined. The final chapter deals with the use of cooperation in the toolshop division. The main and other factors affecting the choice of "product or sell" strategy are evaluated and consequently is decided which strategy is in case of the 5-Axis CNC machining center technology more favourable.
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Photocatalytic Decomposition of Wastewater from the Production of Explosives
Brom, Petr ; Brožek, Vlastimil ; Březina, Václav ; Hlína, Michal ; Mastný, L. ; Novák, M.
Water stabilized plasma generator WSP® H-500, operating on the principle of Gerdien arc was used for the photocatalytic decomposition of furazan- and picraminate-based explosives. The generator emits intensive radiation in the range of 300-660 nm, which allows not only to activate photocatalysts based on TiO2, but also other semiconductor oxides with a narrower band gap, such as tungsten oxide. The photocatalytic decomposition of sewage and slurries containing the potassium salt of 4-hydroxy-4,6-dihydro-5,7- dinitrobenzofurazane-3-oxide (KDNBF) or sodium picraminate (NaC6H4N3O5) was performed using the anatase paste and newly developed photocatalyst produced by the company Precheza a.s. The photocatalytic reactor was built using a quartz tube coil with an internal volume of 650 ml, with a nominal size of the irradiated area of 7.5 dm2 (value reduced by the area of the gaps between coil turns) to enable the flow the processing solution or suspension of up to 10 l / min. The centre of the coil is exposed to the plasma jet with the intensity\nof 80 kW; of which 15 kW is transformed into the light radiation. 11% of the radiation output was used for the presented experiments. The time of exposition was 45 mins and 20 l of solution were treated. In the case of KDNBF, 90% of the compound was decomposed. Moreover, 100% of sodium picraminate were decomposed after 15 minutes into low-molecular inorganic compounds. Advantage of the assembly is the ability to treat highly dangerous chemical compounds in a closed cycle and test selective catalyst
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Surface modification of glass fibers for polymer composites
Knob, Antonín ; Marek,, Aleš (referee) ; Burša, Jiří (referee) ; Čech, Vladimír (advisor)
The doctoral thesis is aimed at preparation of glass fiber reinforced polymer composites with controlled interphase formed by plasma-polymerized tetravinylsilane and tetravinylsilane/oxygen thin films. The thin polymer films of specific physico-chemical properties and thickness were deposited to improve interfacial adhesion of glass fiber/polyester composites. The fiber surface modification was performed by using plasma enhanced chemical vapor deposition in low-temperature RF plasma operating in an various effective power range and different treatment time. Test results were examined in relation to the interlayer thickness and different treatment conditions. The prepared interlayers were analyzed to evaluate physico-chemical composition and properties (XPS, RBS, ERDA, FTIR and spectroscopic elipsometry). Selected mechanical properties were evaluated by AFM. Mechanical response of plasma interlayers was evaluated by short beam shear test and direct method of testing the interfacial shear strength using microindentation. The interphase shear failure was controlled by the shear strength at the interlayer/fiber interface as follows from experimental and model data.
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Book of abstracts. International symposium on experimental methods and numerical simulation in engineering sciences 2016
Kytýř, Daniel ; Zlámal, Petr ; Jiroušek, O.
The International Symposium on Experimental Methods and Numerical Simulation in Engineering Sciences continues the tradition of the Czech-German bilateral symposium founded by prof. Karl-Hans Laermann and prof. Stanislav Holý in 1985. In the following years, the symposium was extensively developed by prof. Josef Jíra. The symposium shall bring together mainly young scientists who are actively involved in experimental solid mechanics, theoretically and practically, in order to exchange experience, to report on the present state-of-art as well as on running research projects, to discuss due questions and problems and to promote the co-operation between individuals as well as between institutions. Therefore in the symposium discussions will play a highly significant role.
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Strategic management company
Vokřálová, Markéta ; Štůsek, Jaromír (advisor) ; Ladislav , Ladislav (referee)
Diploma thesis Strategic management company deals with the issue of the strategic management of the company DNA Energie spol. s r.o. which is operates in area of reactive energy compensation. The primary objective of the diploma thesis is to design an appropriate strategy that would improve the market position and the economic result of the company.
There is literary research in the first part of diploma thesis which deals with the issue of strategic management. There are internal and external environment analysis described. These analysis are applied in the practical part of the thesis.
Practical part deals with characteristics of the company and further analysis of the internal and external environment are drawn up there. The results of these analyses were carried out in SWOT analysis which helped to design various strategic alternatives.
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Measurement and evaluation of exhaust gas production in selected pig operation and design to reduce them.
PRAŽÁK, Jakub
Limitation of emission ammonia and greenhouse gases is a main assumption in the present time for modification the relation between agriculture and environment. The agriculture influences significantly environment only from point of view of landscape creation but mainly in the three fields, i.e. air, water and soil. Agricultureactivity effects considerably all the three fields and particularly intensive breeding of livestock by it?s by ? products i.e. organic remainders and gaseous emissions also have negative impact onto environment. Agriculture produces up to 90 % of worldwide ammonia products. In European measure the amount of ammonia leakage has to be reduced. One of the perspective technologies is exploitation biotechnological products to moderate exhalation of ammonia and greenhouse gases in surrounding stable, on dump and at the application farmyard manure and slurry.
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Wi-Fi network security
Gec, Ivo ; Šimek, Pavel (advisor) ; Vasilenko, Alexandr (referee)
Bachelor thesis is thematically focused on the security of wireless networks operating on frequency bands of 2.4 GHz and 5 GHz. The theoretical part of bachelor thesis is devoted to problemacy of wireless technology. In teoretical part of bachelor thesis are contained various standards, modes of operations, possible attacks, mechanisms and security, which prevent probably attacks or threats. Practical part of bachelor thesis describes a possible design of security for this company, which deals with accounting and taxes.
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Electric Drive Diagnostics and Utilization in Agricultural Machinery
Čedík, Jakub ; Pexa, Martin (advisor) ; Kumhála, František (referee)
This doctoral dissertation thesis deals with rotary mowers, specifically with the issue of mulching.
In the theoretical part the reader is being familiar with the technology of mulching and its importance. Further, the individual types of mulchers and its advantages and disadvantages are described. The literary analysis of energy demands of rotary mowers is stated. Further, the parameters influencing energy demands of the mulcher are also analyzed.
The results of measurement of the energy demands of the mulcher with vertical axis of rotation are presented. The dependency of input power, specific energy consumption and fuel consumption on mass performance of the machine are created. Furthermore, the energy demands was determined, while mulcher was working continuously at the permanent grassland. The energy losses of the mulcher were also analyzed.
The effect of modification of operational and constructional parameters on the energy demands and quality of work of the mulcher wit vertical axis of rotation is studied. From the constructional parameters the shape of working tool, especially cloth angle and rake angle of the tool, and shape of the cover of the mulcher workspace is modified. From the operational parameters the cutting speed and mass performance according to conditions is modified.
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Strategies of Agricultural Development in Angola. Case study: Catabola municipality
Rušarová, Kristina ; Havrland, Bohumil (advisor) ; Jiří, Jiří (referee)
Catabola municipality is one of the most damaged areas of civil war in Angola. Although the climatic as well as soil conditions are favorable for intensive agriculture, small farmers in the municipality are subsistence with the main income source of dried beans, dried cassava and vegetables. Hand-tool technology prevails in the Catabola municipality as it is employed in 95.38 % of the cultivated land of small farmers. The majority of small farmers uses only power of their family members (with a mean of 1.80 kW and standard deviation of 2.37 kW), hired labour is used by 38.0 % of small farmers. In addition, high engagement of child work was found out as 63.88 % of the children age 5-14 are involved in field operations. Primary data collection was conducted in the Catabola municipality in the period July - August 2011, semi-structured questionnaires and focus group discussions were the most frequent methods used. In total, 151 small scale farmers out of 9 villages participated in the survey. 10 factors that influence the dependent variable -- type of farmer regarding technology used on field in combination with hiring of extra labour -- were defined. The factors were statistically analyzed with use of ANOVA. Out of the factors expected to influence adoption of more sophisticated technologies than the hand-tool, increasing in size of the cultivated land and enhancement of education of both parents and children are found to be the limiting factor in the adoption process for use of animal traction or mechanical power from small farmers in the Catabola municipality. Strategy was formulated with use of simplified quantified SWOT analysis separately for animal-draught and mechanical-power technologies. The result can be interpreted as 8.0% assumption of success in animal traction adoption, contrary to 10.1% assumption of failures in mechanization adoption by small farmers in the Catabola municipality. Thus, tractors are not considered as an appropriate technology for small farmers in the Catabola municipality. The most critical criteria in animal traction adoption that should be considered are support of farmers' cooperatives and associations, FFSs, education in the form of general schooling as well as trainings for farmers, blacksmiths, extension workers and animal breeders.
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