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Technology of Production Frame of Case
Tvarůžek, Martin ; Kalivoda, Milan (referee) ; Osička, Karel (advisor)
The bachelor Thesis compares and evaluates the most advanced production technology of components frame of case. These cases are used for induction heating of material. The thesis compares technological features of the material division by means of plasma jet, water jet and laser. It also evaluates the using of the given technology from economic point of view.
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Electrical characteristics of gliding discharge for VOC decomposition
Jeřábek, Martin ; Sysel, Petr (referee) ; Bartlová, Milada (advisor)
The subject of this bachelor's thesis was to get familiar with the characteristics of plasma, its divisinon and diagnostics. In physics and chemismy plasma is considered to be, an ionized gas composed of ions, electrons (and possibly neutral atoms and molecules), which is produced by detachement of electrons from the atomic shell, or by dissociation and ionization of molecules. The plasma is often referred as the fourth state of matter. Attention was given to the description of various types of electric discharge, its characteristics and occurrence. One of the most idey known electrical discharges occurring in nature is lightning, a spark discharge, which occurs in the storm. Lightning is an electric discharge between centres of positive and negative charge of one or more clouds, between cloud and earth, or rarely between the cloud and the stratosphere. The greatest attention is paid mainly to gliding electric arc discharge, called Glide-Arc; it is a representative of on-thermal plasma formed by weakly ionized gas. It has many industrial applications, especially for its high energy efficiency, specific productivity and high selectivity of chemical reactions. Under low and atmospheric pressure, Glide-Arc represents a simple and non-expensive way of non-thermal plasma generation. The discharge is excited between two electrodes of different materials in the pressure range from very low pressures up to the pressures of the order of units of MPa. The gliding arc system consist of horn-gaps electrodes diverging in the direction of the working gas flow. After the application of DC or AC voltage, a breakdown occurs at the smallest distance between the electrodes, and a spark plasma channel drifts (“glides“) in the direction of the flowing gas. The final experimental part deals with the measurement of VA characteristics and oscillation characteristics of the current, and with the determinativ of gliding arc ignitron for selected of nitrogen and methane gases at various flow rates. The values of ignition voltage for variol mixtures of gases have been compared. Furthermore, the properties various combinations of gases at different gas flow rates have been evaluated. Measurements were carried out in the plasma laboratory of the Faculty of Chemistry BUT in the plasma reactor at the atmospheric pressure.
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Production of sample of the plasma cutting machines
Klepárník, Ivo ; Slaný, Martin (referee) ; Kalivoda, Milan (advisor)
The main focus of this thesis is on plasma cutting. In this thesis are considered the pros and the cons of plasma cutting technology. Furthermore it focuses on the construction of a plasma cutting machine and the selection of appropriate components for positioning as well as cutting. It concludes with the general problematic of construction of such a machine and also a detailed technological process of manufacturing two components.
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Thin films prepared in RF glow discharge and their physico-chemical properties
Bránecký, Martin ; Boušek, Jaroslav (referee) ; Čech, Vladimír (advisor)
Theoretical part of this master thesis was focused on literature recherché dealing with the formation of thin films, plasma, plasma analyses using mass spectrometry and plasma polymerization. Further, this section describes the analysis of thin films using optical methods such as spectroscopic ellipsometry and FT-IR spectrometry. Experimental part describes the materials which are used for the preparation of thin films as well as a description of the equipment for preparation of thin films using a technology of plasma-enhanced chemical vapor deposition (PE-CVD). Control of deposition conditions and monitoring of plasma with its products result in high reproducibility of thin films. The last part of the thesis describes the results of measurement of the first group of samples and their ellipsometric, mass spectrometry and FT-IR evaluation with respect to the deposition conditions.
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Study of plasma species by mass spectroscopy
Bureš, Michal ; Čáslavský, Josef (referee) ; Čech, Vladimír (advisor)
Plasma polymer films of tetravinylsilane and mixture of tetravinylsilane and oxygen gas were deposited on silicon wafers. Oxygen gas was mixed in tetravinylsilane to improve the compatibility of thin films on glass substrates. Mass spectroscopy was employed during the cleaning of the deposition chamber to check residual gases and process gases, during plasma deposition to monitor neutral plasma species and to follow plasma stability.
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Electrical features of barrier discharge for microorganism sterilization
Bernát, Jan ; Pfeifer, Václav (referee) ; Bartlová, Milada (advisor)
This thesis deals with barrier discharge through gases from the point of view of electrical attributes and processes that, which are going on in a discharge. The research of a discharge itself is preceded by theoretical discourse about plasma and its attributes and basic information about barrier discharge. Second part deals with processing measured data on an experimental device and is followed by making deduction. The main role is relating instantaneous power P[W] and power drain Pel[W] to supply voltage. Nitrogen and argon gases were used and the experimental measuring device was set in different configuration of gas flow velocity, distance between electrodes, used frequency of a supply voltage and its different level. An algorithm decribing proceding with another data measuring is described in this thesis. The scope of the thesis does not allow for thorough examining of each aspect, which was measured or deduced from data analysis. However the the thesis addresses these aspects and suggests further research.
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Creating a knowledge base for the diagnosing of diseases
Macháček, Daniel ; Steinerová, Kateřina (referee) ; Jirsík, Václav (advisor)
This bachelor thesis is focused on problematic of creation knowledge base. It is describing basics of expert systems, their function and possible usage in modern world. In result of this thesis is knowlenge base in web aplication NPS able to diagnose diseases of hematology-oncology and that is proving possibility for use in real life. Knowledge base was created in cooperation with experts in the medical field and contains real data.
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Theoretical - practical view of the levitation of the lifter
Buday, Matej ; Bartlová, Milada (referee) ; Zdražil, Vladimír (advisor)
Levitation and its effects becomes a huge trend of modern physics. It is very important to be accurate and patient in the research. Representative of the theory, which we are examining, is a lifter and its levitation in electrostatic field. Air ionization is produced by high voltage connected to the lifter’s electrodes and a beam of plasma will surround a thin wire electrode. The levitation effect will appear, if there is right magnitude of electric field intensity and right method of lifter construction.
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Fibre reinforcement with plasma in cement composites
Žižková, Lucie ; Hela,, Rudofl (referee) ; Bodnárová, Lenka (advisor)
The usage of polymer fibres can be increased by the new progressive method of the plasma treatment. This thesis is focused on verification of the influence of the low-temperature treatment on polymer fibres´ surface used in concrete. The treatment of polypropylene fibres in low-temperature plasma is described in the theoretical part. The impact of the treatment on the volume differences of cement composites is also evaluated. The influence of the addition of commercially available fibres and plasma treated fibres on the volume differences of cement composites is also experimentally verified.
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Preparation and characterization of plasma activated water for bio applications
Lemonová, Hana ; Matěj,, Klas (referee) ; Krčma, František (advisor)
The aim of this master thesis is the preparation and characterization of plasma activated water (PAW) prepared by dielectric barrier discharge at atmospheric pressure in air for the future applications in agriculture and medicine. The theoretical part is focused on plasma activated water and its effects on seeds and plants. The work also deals with the preparation and application of PAW in the world. Various types of plasma discharge configurations suitable for its preparation are described here. In the experimental part of the master thesis, distilled and tap water were chosen for activation. The concentrations of active particles in PAW generated by DBD such as nitrites, nitrates and hydrogen peroxide were determined. The value of the concentration of active particles changes probably due to mutual interactions when nitrites are oxidized by hydrogen peroxide to nitrates. Physical properties of PAW such as conductivity and pH were also characterized. After the preparation of PAW, the conductivity increases due to the increase in the concentration of active particles formed by dissociation and ionization of water molecules by plasma. The particles presented in the air, which are dissociated and ionized by plasma, also diffuse into the liquid, and contribute to this increase. The decrease in pH also corresponds to an increase in the concentration of hydrogen ions and the formation of nitric acids. Another aspect of this work was to study plasma activated water during the first eight hours after its preparation and to determine its properties. We have found that PAW prepared from tap water retains its characteristic properties for at least 8 hours and distilled water for 6 hours. In the master thesis, the analysis of plasma discharge was performed using optical emission spectroscopy. OES measurements were performed in the wavelength range 300 to 800 nm. The second positive nitrogen system (N2 (C 3u) N2 (B 3g)) and the first positive nitrogen system (N2 (B 3g) N2 (A 3+u)) were identified in the overview spectrum. Molecular nitrogen ions, OH· radicals, atomic oxygen and atomic hydrogen can be observed in the spectrum, too. The dielectric barrier discharge was also captured using a high-speed camera, and the recording shows the occurrence of multiple discharges that are spatially as well as temporary unstable.
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