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Optimization of the experimental parameters for laser induced breakdown spectroscopy (LIBS) of selected plant samples
Prochazka, David ; Novotný, Karel (referee) ; Kaiser, Jozef (advisor)
This diploma thesis describes optimization of the experimental parameters for Laser-induced breakdown spectroscopy of plant samples. First part deals with the theoretical method of LIBS and explains the principles and terms. In the next part there is described device which was used for measurements. Main part of diploma thesis describes creation of program for measurement-automation. Main task of program was to solve the connection of autofocus on the sample with the sample automatic movement. Furthermore are described and elaborated specific measurements for optimization of the experimental parameters for Laser-induced breakdown spectroscopy of plant samples.
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Corrosion layers removal in low-pressure plasma
Kujawa, Adam ; Grossmannová, Hana (referee) ; Krčma, František (advisor)
A plasmachemical reduction of corrosion layers on copper was studied. In this case two series of copper samples were prepared and putted in two corrosive environments for one week. The first corrosive environment contained a concentrated nitric acid and the second environment contained a concentrated sulfuric acid. Samples thus prepared were ready to be plasmachemicaly treated. The plasmachemical reductions took place in low-temperature, low-pressure, non-isothermal, high-frequency-inducted hydrogen plasma on the Faculty of Chemistry in University of Technology in Brno. The discharge was generated in continual or pulse mode with changeable pulse ratio. To monitor the reduction process an optical emission spectroscopy was used. The radiation from plasma discharge was measured by an optical spectrometer in the intervals of 1 to 10 minutes. An object of our concern in collected spectrum was the radiation of OH radicals with electromagnetical wavelenght in a range of 305 – 330 nm, and which were produced in a reaction between the hydrogen radicals and the oxygen atoms, contained in the corosion layers. A rotation temperature of plasma was calculated from the spectrums of OH radicals in a dependence of discharge conditions. Gathered findings will give us a better knowing of this conservation technique, that is used for treatment of the corroded surfaces of the archeological artifacts, and will also allow more provident appliance of this method on a copper historical objects.
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Unconventional machining processes
Exnerová, Jitka ; Mouralová, Kateřina (referee) ; Kalivoda, Milan (advisor)
This thesis deals with the methods of the unconventional machining. The first part outlines the history of the machining methods, their characteristic and use follows. The second part aims at the method of the water jet, its technology, safety use, its advantages and disadvantages. Subsequently the thesis presents selected companies dealing with water jet cutting technology. At the end the thesis presents the environmental impact of the water jet cutting.
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Production of handrail holder
Ryšavý, Jan ; Varjan, Matúš (referee) ; Peterková, Eva (advisor)
Economic and technological analysis of possible methods of production real part. The basic theoretical knowledge of selected production methods and their application in practice. The division of production methods for various production series of part using economic evaluation.
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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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