|
|
Microplasma Noise as a Diagnostic Tool for PN Junctions of High-Voltage Rectifier Diodes
Raška, Michal ; Chobola, Zdeněk (referee) ; Hájek, Karel (referee) ; Koktavý, Pavel (advisor)
The doctoral thesis deals with diagnostics of local defects in PN junctions and brings new information about microplasma noise behaviour and its usage for the temperature changes detection inside PN junctions. Defects in PN junctions are the source of microplasma noise. There were deviations observed in microplasma noise from the common known rectangle shape pulses during the measurements. These deviations were correlated with the temperature change directly in the defect area and in the defect area surroundings. Generation and recombination coefficients are commonly thought to be constant. However, these coefficients were observed to be not stable with time and this effect is explained in this work. The doctoral thesis then focuses on the PN junction parameters determination in the case when it is not possible to define unambiguously whether it is abrupt or linearly graded PN junction. The most significant parameters which are to be determined are barrier capacity, diffusion voltage and depleted area width in dependence on the voltage. The correlation between local avalanche discharge in PN junction and negative differential resistance appearance on VA characteristics of reverse-biased diode was qualitatively verified. The last important point in the work is computer modelling of temperature behaviour in the defect area and its surroundings during local avalanche breakdown. Thus the method of real diodes heating area parameters determination was introduced.
|
|
|
Thermodynamic method for assessing hydraulic machine efficiency
Mizera, Ladislav ; Ševčík, Petr (referee) ; Habán, Vladimír (advisor)
The master´s thesis contained basic information about the method of thermodynamic efficiency of hydraulic machines. The first part briefly mentioned our opinion on the most widely used method for determining the efficiency of hydraulic machines. Another section of thesis is characterization and measurement procedure using the thermodynamic method. Another section describes measurements of water plants and laboratory measurements, which took place in the past. The final part describes the results of laboratory measurements, which took place in the lab of VUT FSI Brno, and evaluating and comparing the results.
|
|
|
Mixing and kneading machine
Kopáček, Petr ; Anderle, Martin (referee) ; Prokeš, František (advisor)
This diploma work deals with design of the mixing and kneading machine which works with heated mixed components. The components consist of PET, HDPE, silica sand and additives. First, there is introduced knowledge from accessible sources, which are concerned with the theme. Then follows projection of variants and selection of suitable solution. With the help of obtained konwledge and the chosen variant is performed design proces. In the end is created a concept assemble of the machine. The design proces includes projecting of the individual parts, strength verification of the basic elements and design of heating device.
|
|
| |
|
|
Production of support by forming
Palán, Robert ; Novotný, Karel (referee) ; Kopřiva, Miloslav (advisor)
PALÁN Robert, Production of support forming.A graduation thesis of master´s studies, Mechanical engineering, Department M2307 Metal forging technology, Specialization 02 Forming, Welding, 2. graduate, 2. year, school – year 2007/2008. FSI VUT Brno, ÚST Department of Metal Forging Technology, May 2008, page NO 66, picture NO 36, chart NO 8, suplement NO 12 The graduation thesis, drew up with in the frame of engeneering studies department M2307, submits a concept of a production by forming. A materiál of a forget piece is steel ČSN 12 050, provided as a semi – finished product in a form of a bar 210 mm, lenght 4 000 mm. The particular dimension stocks with be cut from it to forge out a part. Production work is 100 000 pcs. Based on studies of technologies, suitable for producing the part a specific two stage technology of a drop forging was chozen on a vertical forging press LMZ 6 500, with induction heating of the semi – finished product and a product – trim of fin and pellicle or a trimming press LDO 315 A/S. For this alternate all the required calculations are realized of swages and all the necessary machines for the production of are quested enganget part.
|
|
|
Analysis of the economic efficiency of a solar system
Mikl, Antonín ; Pithart, Jan (referee) ; Macháček, Jan (advisor)
The Master’s thesis deals with the processing of solar thermal systems for heating hot water, outdoor swimming pool and heating selected house. Introduces us how we can use the sun for the production of thermal energy through solar collectors. Furthermore, the basic components of the solar system and the types of collectors used. After this summary on the present state be the calculation of the system and fixing the price of the investment. The economic part of the evaluate if this system to invest, eventually appoint a return on investment.
|
|
|
Heat pumps for heating and hot service water preparation
Valášek, Martin ; Hrnčířová, Michaela (referee) ; Kracík, Petr (advisor)
This bachelor’s thesis is aimed to describe heating and water warming in the detached houses by basic technical devices and there are suggested various types of heat pumps for a particular object. These heat pumps are compared technically and economically. In the beginning of the thesis there is a summary of the possible ways of the house heating and water warming systems, such as heating by electric power, by gas, by solid fuel or the centrally distributed heating. Then the thesis concentrates on heat pumps. There are described various types of heat pumps, also their advantages and disadvantages. There were chosen four main types of heat pumps – air/water, air/air, water/water and earth/water – and with each type there’s constructed a plan for a low-energy house heating. This house is located in Vyškov and there’s thermal loss of 6 kWh and water-warming of a capacity of 260 l per day. At last there were used economical calculations, which shown, that the water/water heat pump has the shortest return rate in comparison with a gas-using heating system – 5 years. Considering the lifespan of the heat pumps – 10-20 years – all the heat pumps are profitable except for the air/air heat pump. The investment in this heat pump doesn’t return.
|
|
|
Solar heating tap water
Kracík, Petr ; Baláš, Marek (referee) ; Fiedler, Jan (advisor)
This bachelor thesis deals with the heating of hot service water by means of solar energy through solar collectors. At the beginning the author describes the most frequent methods for heating of service water in Czech houses with the help of electrical energy, fossil fuel, gas and central heat supply, including the input expenses for buying equipment. The author describes a solar system and his basic elements and suggests two variants with supplement heating by means of electrical energy, which compares with electrical heating of service water. The overall thesis is conceived as a review of possibilities of heating hot service water in households with economical budget at the end of the work.
|
|
| |
|
|
Mikrovlnná plastifikace dřeva
Malík, Tomáš
The bachelor thesis concerns wood processing using microwave radiation, which represents a special case of dielectric heating. The nature of the thesis is to compile theoretical information about microwave wood processing. Introduction to the thoery of dieletric and it's properties in wood. Model application of microwave technology in wood processing industry. Advanteges over other common production technologies.
|
guest ::
