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Al-alloy die-castings-trends in industrial
Rýdel, David ; Pacal, Bohumil (referee) ; Čech, Jaroslav (advisor)
The objective of this diploma thesis is to state the influence of porosity, DAS and shape factor on mechanical characteristics for the cast transmission cover made in Kovolit Modrice a.s.Which was molten from AlSi9Cu3. It was used an imaging software (Olympus Five) for classification of metallographical structures.
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Study of the main factors affecting quality in technological processes
Talanda, Ivan ; Nová, Iva (referee) ; Čech, Jaroslav (advisor)
The aim of this bachelor’s thesis is to theoretically describe porosity problems of casts of aluminium alloys that are made via die casting technology. The thesis is focused on influence of porosity on mechanical properties of casts. Theoretical dependencies were verified in experiment, which is based on new measured data and data witch were taken from diploma theses and science articles written by other students of the University of Technology in Brno. The samples used in experiment come from engine blocks, which were made by technology of die casting or die casting with local squeeze casting.
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Design of synchronous linear motor thermal network
Čech, Jan ; Toman, Marek (referee) ; Knebl, Ladislav (advisor)
The first part of this thesis deals with the study of linear motors. The introduction of the thesis deals with the brief description of the linear motor, including its accessories. This part explains principle of linear motors, their general advantages and disadvantages. The next section contains an overview and division of the currently used linear motors. The second part deals with the theoretical description of forms of heat transfer. The third part of the thesis deals with the design of an equivalent thermal circuit model of a linear iron-core linear motor with permanent magnet. Hereafter, the proposed design will be used to calculate the temperatures of the individual motor units. The temperatures are later compared with the results obtained with finite element method.
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Analysis and design of the use of brownfields in Pardubice
Pechánek, David ; Hlavinková, Vítězslava (referee) ; Čech, Josef (advisor)
This diploma thesis is focused on analysis and design of new use of brownfields. The solved brownfield is located on the territory of the statutory city of Pardubice. The thesis first describes the current state of knowledge concerning the issue of brownfields, including examples of already solved, similar projects. Furthermore, the methods that will be used in the creation of the design are presented and the initial data related to the solved brownfield are given. The proposal part of this diploma thesis presents a proposal for a new use of one of the brownfield subsectors and describes the phasing of construction. Then, the individual variants of the design are introduced, differing in the different trading of the building after its construction. These variants are then analyzed and compared. Using the analysis of HAB, the best possible solution variant is selected and a procedure for its implementation is proposed.
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Influence of insulation of a house in Slavice on expenses related to the operation of the property
Pokorná, Jana ; Čech, Josef (referee) ; Nykodýmová, Veronika (advisor)
This master´s thesis deals with insulation of the house and it's costs. First part describes the energy performance of building, different methods of thermal insulation and types of thermal isolation. This thesis evaluates the influence of thermal insulation of residential building design for expenses associated with operating the property. This thesis uncludes thermal technical assessment of the condition of the house and then heat the assessment of the options for the thermal insulation on its economic return. In conclusion, the assessment of individual variants insulation is calculated as a simple payback period and the effect on price of this house.
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Contribution to the construction of cost and energy efficient family houses
Čech, Josef ; Mohelníková, Jitka (referee) ; Gašparik,, Jozef (referee) ; MBA, Pavel Slováček, (referee) ; Hrazdil, Václav (advisor)
Dissertation focuses on the verification of construction family houses made of concrete shell block with internal thermal insulation system. The construction technology is transferred to the Czech Republic from France. The work focuses on building envelope. The suitability of implementation is assessed on the basis of verification selected thermal technical requirements placed on building envelope. Requirements are specified by legislation in force in the ČR. The verification was performed by using software simulations and measurements on realized buildings. Critical areas of construction technology were identified on the basis software simulations and measurements on site. It was suggested solution, in which critical areas comply the thermal technical requirements. The building envelope was checked also using the thermography imaging on site. Continuous measurement of interior temperature was used to evaluate thermal comfort in the room. In the completed buildings was tested airtightness of the building envelope, which revealed other critical areas of the building envelope. Critical areas are necessary to solve with sufficient care. The economic cost of implementing each variants of exterior walls made of concrete shell block with internal thermal insulation were compared with the economic costs of implementing external walls made of burnt clay hollow blocks and made of burnt clay hollow blocks with external thermal insulation system ETICS. Subsequently, the economic return was calculated for individual variants of external walls made of concrete shell blocks with internal thermal insulation. From the environmental viewpoint was made comparison of production greenhouse gas CO2 and SO2 (cause acid rains) during the life cycle of the individual variations of exterior walls made of concrete shell blocks with system of internal thermal insulation, exterior walls made of burnt clay hollow blocks and burnt clay hollow blocks with external thermal insulation syst
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Mg-alloy die-castings - trends in industrial
Svoboda, Rostislav ; Juřička, Ivo (referee) ; Čech, Jaroslav (advisor)
The aim of this thesis is to determine influence of porosity and shape-factor over mechanical properties, performed on cast samples from Aalen foundry (Germany), that were high pressure die casted from AZ91 D Alloy. Evaluation of these quantities was done using computer software Olympus Five. Measured values were subjected to statistical analysis in order to eliminate gross errors and determine linear dependence between mechanical properties and porosity eventually voids shape factor.
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Steam boiler with grate firing , burning coal or wood biomas 200 t/ h, 9,3 MPa 520°C
Čech, Jaroslav ; Hudeček, Mirko (referee) ; Skála, Zdeněk (advisor)
The aim of the work is the design of a grate boiler of 200 t . h-1 output, which will burn brown coal or wood chips. The work is divided into several parts. First, stoichiometric calculation and the calculations enthalpy of flue gases and air are performed. After calculating the heat balance and loss of the boiler was counted boiler efficiency. The design of individual heating surfaces is proposed and at the end are controlled the overall heat balance of the boiler. The calculation is supplemented by drawings.
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Segregation during solidification in austenitic-ferritic stainless steels
Kejha, Richard ; Čech, Jan (referee) ; Pernica, Vítězslav (advisor)
The master thesis deals with processes of segregation in austenitic-ferritic stainless steels. The introductory part consists of characteristics features of austenitic-ferritic steels and theoretical analysis of segregation processes. The second part shows practical measurements of segregation in experimental casting. Macrosegregation was measured on a spectrometric analyzer and simultaneously solved in the simulation program MAGMA. The aim of this thesis is to verify the effect of solidification time and dwell time between liquidus and solidus temperature on the chemical heterogeneity of duplex stainless steel casting of about 500 [mm]. Chemical heterogeneity was solved for selected alloying and accompanying elements such as C, Mo, Ni, Mn, Cr. The microsegregation was not addressed. Comparison of the mechanical properties of cast and heat treated duplex steel was done by tensile testing of samples cut from the center of the casting.
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