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Design of plasma cutting machine
Vejrosta, Pavel ; Tůma, Zdeněk (referee) ; Pavlík, Jan (advisor)
This bachelor´s thesis is focused on the design of plasma cutting machine. The work begins with an introduction to plasma itself, covering the theory related to topics important for understanding the issues of plasma cutting and the operation of plasma cutting machines. This section is followed by review and market research in field of plasma cutting machines. Furthermore, the thesis establishes specific requirements and characteristics that are necessary for the actual design of the machine. The next section proposes various solution concepts and selects the optimal variants of the main parts of the machine, including supporting structure, type of drive, linear guides, electric drive, plasma torch, power source, safety and other elements. The selected parts are verified using design calculations. The actual design of the machine and the drawing documentation are created in Solidworks 2023. The conclusion of the thesis presents the final design, proposes possible improvements, compares the results with the set goals, and gives a final evaluation of the designed plasma cutting machine.
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VUV spectrometer for vacuum interaction chamber
Drobil, Tomáš ; Šerý, Mojmír (referee) ; Novotný, Jan (advisor)
This thesis deals with the design of a VUV spectrometer for the Laser-induced breakdown spectroscopy (LIBS) method. A prototype using commercially available components was designed and tested. In addition to the actual development of the optical and mechanical design and the selection of the detector, a thorough research of elements emitting in the VUV region was carried out.
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Study of electrical discharge initiated chemical processes in Titan like atmosphere in stationary regime
Zbytek, Filip ; Chudják, Stanislav (referee) ; Krčma, František (advisor)
The aim of the presented bachelor's thesis was the study of chemical processes initiated by electric discharge in an atmosphere similar to that of Titan. This bachelor's thesis focuses on simulating Titan's atmosphere at normal laboratory temperature and atmospheric pressure. Titan's atmosphere is mainly composed of nitrogen, which constitutes 98 % of the atmosphere. For the simulation, spark and glow electric discharges generated in a special reactor were used. Measurements were conducted with varying CH4 flow rates of 0, 1, 2, 3, and 4 sccm. The first part of the measurements was conducted for the spark discharge and the second part for the glow discharge, both under the same conditions. The synthesized gaseous products were analyzed using proton transfer reaction time-of-flight mass spectrometry (PTR-ToF-MS). Mainly simple nitrogenous aliphatic hydrocarbons were detected, but with increasing CH4 flow, the formation of more complex aromatic hydrocarbons occurred for both discharges. The composition of the plasma and its diagnostics were investigated using optical emission spectrometry (OES). Measurements using proton transfer reaction mass spectrometry and optical emission spectrometry were conducted simultaneously.
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Influence of plasma activated water on seed germination and quality of corn
Kovařík, Martin ; Zlámalová Gargošová, Helena (referee) ; Kozáková, Zdenka (advisor)
The bachelor's thesis deals with the effect of plasma-activated water on corn germination. After water comes into contact with plasma, the water changes its chemical composition and thus, it acquires new properties that can be used in agriculture. The theoretical part is divided into two basic parts. At the beginning of the first part, plasma is briefly characterized, and then this part deals with plasma-activated water, its formation, physical and chemical properties, and at the end of this part, its use. The second part of the theoretical part is devoted to the germination of plants, external influences affecting germination and statistical evaluation of germination. At the end of the theoretical part, this thesis deals with the ecotoxicity of plants. The content of the experimental part was the preparation of PAW, its subsequent application to corn seeds and the study of its effect on germination and plant quality. PAW was created from distilled or tap water using three different plasma systems and the effect of each PAW on the seeds was compared with that of each control sample. The obtained results indicate a positive effect of PAW on seed germination, but the final hypothesis would require more extensive experiments in different environments, especially in soil.
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Studz of direct and indirect plasma application on onion seeding bulbs
Krejsová, Lenka ; Enev, Vojtěch (referee) ; Krčma, František (advisor)
Nowadays, agriculture is based on conventional methods that involve the application of pesticides, agricultural chemicals and fertilizers. These substances have a negative impact on nature and human health, so more environmentally friendly methods are being sought. This thesis deals with the analysis of fragrances in onions treated with plasma before planting. The treatment was carried out to see if it would improve onion growth while maintaining or increasing the fragrance content. The theoretical part deals with the soil and it is characterization methods, plasma, quantitative and qualitative methods for the determination of volatile substances. It contains the principles of UV-VIS spectrometry, atomic absorption spectrometry (AAS), mass spectrometry (MS) as well as tandem connection of gas chromatography with mass spectrometry (GC–MS). The experimental part was carried out over a period of three years at 22 sites. The preparation and analysis of soil samples are described, which was also evaluated. Furthermore, the procedures for treating the bulbs with corona discharge and plasma-activated water before planting were described. In total, four treatment variants were carried out and bulbs from the fifth variant were not additionally treated. Each treatment variant was planted in four replications of ten bulbs each. Twenty selected grown onions from one site were individually converted to liquid samples and the saturated vapor was analysed by proton transfer reaction time of flight mass spectrometry (PTR–TOF–MS). Thanks to this analysis, the concentrations of volatile substances were determined. Some samples were analyzed by gas chromatography with mass spectrometer as detector to identify the compounds. Subsequently, the data were processed and evaluated. From the results obtained, it is evident that plasma treatment can be useful for the treatment of onions in agriculture, because it confirmed harvest increase without decrease of fragrances concentrations. Thus, it is necessary to carry out experiments on a larger scale in the future.
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Influence of plasma and plasma activated water on fungi Aspergillus niger
Žitný, Michal ; Čechová, Ludmila (referee) ; Kozáková, Zdenka (advisor)
The thesis deals with the issue of decontamination of Aspergillus niger mold using plasma, plasma-activated water and their combination. The theoretical part concerns the effects on the general properties of plasma, its generation, effects on microorganisms known so far and its use in industry with a special focus on medicine. It also focuses on the generation and characterization of plasma-activated water, its effects on bacteria, yeasts and fungi and its use. It also deals with the description of fungi, their occurrence and their sterilization. Part of the theory was aimed directly at the fungus Aspergillus niger. Its cultivation and its industrial uses, such as its use for the cultivation of citric acid, were described here. The experimental part deals with the characterization of plasma-activated water generated using a torch jet. The influence of the supplied power on the formation of particles in plasma-activated water was monitored. The decontamination effect of the plasma, generated by the torch jet, alone and in combination with plasma-activated water generated by alternating and direct current is monitored. The characterization of plasma activated water was performed with 20 ml of distilled water at a carrier gas rate of 2 l/min and a power of a microwave source of 9 and 12 W. The decontamination effect of plasma and its combination with plasma-activated water was observed by inoculating 100 l of a ten-fold and a hundred-fold diluted treated mold culture on Petri dishes with malt agar. The evaluation of the effect was carried out by counting the grown fungal colonies and subsequent comparison with control samples. All measured and obtained data were processed in the results. Plasma activated water generated by the torch jet has been found to contain higher concentrations of nitrogenous substances and lower concentrations of hydrogen peroxide, with the generated nitrate concentrations being higher at lower output than at higher output. DC-generated plasma activated water containing low concentrations of nitrogenous species and a very high concentration of hydrogen peroxide compared to PAW generated by a torch jet. Furthermore, plasma-activated water generated using a high frequency source contains minimal concentrations of nitrogenous substances and slightly elevated concentration of hydrogen peroxide in regard to torch jet PAW. The highest decontamination effect of all the methods used was the combination of plasma and plasma activated water, prepared by a plasma nozzle using direct voltage, when the plasma was applied first. On the contrary, the least effective method was the application of plasma and plasma activated water, generated by high frequency voltage. Limiting oxygen access had almost no effect on direct plasma treatment, but other methods were significantly affected by it. The greatest difference in decontamination effect was observed for the combination of plasma and plasma activated water, generated by high frequency current, where the difference was up to 30 %, but all methods had a significant decontamination effect compared to the control.
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Biomedical applications of polycaprolactone nanofibrous mats
Dvořák, Pavel ; Přibyl,, Jan (referee) ; Zajíčková, Lenka (advisor)
The diploma thesis deals with the treatment of polycaprolactone (PCL) nanofibers. PCL fibers were subjected to the deposition of plasma amine polymers in a low pressure pulsed radiofrequency capacitively coupled discharge using cyclopropylamine monomer (CPA). Collagen as an extracellular matrix (ECM) protein was immobilized and cell proliferation on the modified nanofiber surface was monitored. Untreated PCL fibers were also subjected to the deposition of an antibacterial copper layer, and the fibers were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and energy dispersive spectroscopy (EDX).
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Temporally and spatially resolved diagnostics of an electric arc
Holcner, Oldřich ; Šimek, David (referee) ; Kloc, Petr (advisor)
This batchelor thesis "Temporally and spatially resolved diagnostics of an electric arc" deals with the investigation of plasma temperature in an arc formed by evaporation of copper wire. It is an optical method based on determination of temperature from intensity of spectral lines. In this batchelor thesis we explain how spectral lines are formed and how to determine the temperature. In the practical part we process discharge and show the time evolution of temperature at the measured points.
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Enhancement of optical diagnostics of the switching arc
Samohejl, Matěj ; Kloc, Petr (referee) ; Valenta, Jiří (advisor)
This master´s thesis si focused on determinig methodology of optical diagnostics of the switching arc using the high-speed camera Photron SA-X2. The thesis contains basic rules for proper setup of the measurement system and the rules to adjust the camera exposure. The experiments were performed on the prototype of a parametric switching chambre, while the majority of source materials was derived from the requirements of another study which was aimed on the movement of the electode spots. The process of the first adjustment of the camera, a record edit options for the presentation purposes and the process of the 3D model design of the switching arc in SketchUp software was stated. Paper contains a comparsion of the spectral filter effect and neutral density filter effect on the final record as well. The part of the work outputs are the 3D model of the switching arc and the supporting record editing software. The paper results show a degree of the inaccuracies in a optical diagnostics made from only one direction caused by the lack of the information about third dimension.
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