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Study of chemical processes initiated by electrical discharge in liquids
Možíšová, Aneta ; Zlámalová Gargošová, Helena (referee) ; Kozáková, Zdenka (advisor)
This Bachelor´s thesis in the first part describes the process of ignition of the plasma discharge in water solutions, the generation of the particles that are generated during the discharge and their subsequent analysis by appropriate analytical methods. The second part focuses on specific cases of the use of the plasma discharge in the environment of selected electrolyte, phosphates were selected for individual experiments and for the comparison of sodium chloride. Phosphates were chosen mainly because of their stable pH as a possible benefit in discharge. The aim is to obtain the most ideal environment for the ignition of the plasma discharge and to optimize the method, which could subsequently be used for medical purposes, especially when sterilizing tools
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Design of algorithms for a continuous steam quality measurement system
Hanák, Tomáš ; Tofel, Pavel (referee) ; Holcman, Vladimír (advisor)
This bachelor thesis deals with proposal of algorithm for continuous system of sterilizated steam. At the beginning we deal with the process of sterilization and its methods. Later on we talk over about the saturated steam and parameters of saturated steam. At the end of the bachelors thesis we discuss about current measurement of sterilization steam quality. Then, the procedure of simultaneous measurement of sterilization steam quality is described here. The last part is the evaluation of measured data and presentation of their results.
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Polymeric biocompatible materials
Matlák, Jiří ; Stránský, Lubomír (referee) ; Molliková, Eva (advisor)
The aim of the bachelor’s thesis is polymeric biocompatible materials. In the first part the problematic of the biocompatible materials is discussed and the basic terms are explained. In the next part are described polymeric materials and their chemical composition, mechanical and chemical properties and examples of applications.
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Continuous measurement of the quality of steam
Rageh, Akram ; Sedlák, Petr (referee) ; Holcman, Vladimír (advisor)
Diplomová práce se zabývá měřením, analýzou a následným nalezením vhodných fyzikálních parametrů pro analýzu kvality syté sterilizační páry. Tato práce si klade za cíl určit, kritické parametry systému vyvíječe páry pro provoz dle norem ČSN. Dílčí částí projektu je popis fyzikální sterilizace, syté páry, metod a senzorů pro kontrolu sterilizační páry.
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Study of plasma interaction with yeast Candida glabrata
Trebulová, Kristína ; Lehocký, Marián (referee) ; Krčma, František (advisor)
The main subject of this diploma thesis is the study of low temperature discharges´ effects on the yeast Candida glabrata (C. glabrata). Cold atmospheric-pressure plasma (CAPP) technology has achieved a great deal of attention in recent years, due to its positive attributes, including high efficiency against a wide range of microorganisms, ease of operation, economic simplicity and also environmental friendliness. The research of CAPP focuses mainly on the applications involving the treatment of cancer and superficial infections as well as sterilization technologies in medicine, food and agriculture. Various effects and also some mechanisms of inactivation of bacteria and tumor cells have been explained over the last decade but the effects and mechanisms of fungi inactivation have not yet been sufficiently investigated. The aim of this work is to verify the effects of chosen low-temperature discharges on the model yeast example C. glabrata, in order to establish basic plasma set-up for further studies and experiments in vivo and to expand a global knowledge about the antifungal effects of CAPP. In this study, 5 different discharges, namely: microwave (unipolar and surface wave) in the form of plasma torch, transient spark, corona discharge in the form of corona pen and dielectric barriere discharge (DBD) in the form of DBD pen were tested. All discharges were tested by direct application onto a 24-hour inoculum of C. glabrata inoculated on agar plates. The results were evaluated based on the size and stability of the inhibition zones formed in the post treatment cultivation. From the individual measurements optimal conditions for testing the inhibitory effects of low temperature discharges on the selected yeast were determined. The microwave discharges (unipolar and surface wave) were chosen to be the most effective in the inhibition of C. glabrata. The measurements were therefore pursued with these discharges under selected conditions corresponding to chosen application of sterilization of surface infections in living organisms. The unipolar microwave discharge was chosen to be the most effective discharge for the potential treatment of superficial candidiasis. The indirect effect of plasma was also investigated using plasma activated liquid (PAL) on inoculated yeast culture. PAL was prepared using 3 different discharges: Dielectric Barrier Discharge (DBD), Unipolar Microwave Discharge and Electric Discharge in Liquid. The results of this work prove significant inhibitory effects of CAPP on the yeast C. glabrata, within the limits of in vitro cultivation and the so-called flat biology. The overall inhibitory effects are directly proportional to the irradiation time, the magnitude of applied power and also the area covered by the discharge. In terms of the initial cell concentration an indirect dependency can be observed, but it can also be stated that this factor is less significant compared to the other examined factors. Observations of the effects of plasma activated liquid (PAL) indicate that a single application of PAL under selected conditions is not alone enough for successful inhibition of C. glabrata.
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Study of the sterilization effect of temperature and UV light present in dielectric barrier discharge
Kramárová, Petra ; Grossmannová, Hana (referee) ; Kozáková, Zdenka (advisor)
The main theme of this bachelor thesis is to study the effect of temperature and UV radiation to the total sterilizing effect of dielectric barrier discharge. Sterilization is a process, which can eliminate all forms of life. The presented bachelor thesis discusses plasma sterilization, which is one of the method, which are suitable for sterilization of heat and chemical sensitive materials. This sterilization method is effective on the wide spektrum of procaryotic and eucaryotic microorganisms. Basically, the main inactivation factors for cells exposed to plasma are heat, UV radiation and various reactive species. In my thesis a dielectric barrier discharge (DBD) operating at atmospheric pressure was used for the sterilization of the samples. Plasma was generated in argon and nitrogen. According to the previous measurement the best sterilization results were observed using plasma power input 2 562,96 mW•cm-3 (argon) a 2 044,44 mW•cm-3 (nitrogen), therefore the same plasma power input was applied during our measurement. Fungi spores of Aspergillus niger were used as model organisms. Whatman paper No. 1st was used as the carrying medium. Each sample series was exposed to plasma for 5, 10, 20, 40, 60, 120 and 180 s. In order to separate the effect of UV radiation generated by DBD the quartz glass transmitting UV radiation was used. During the plasma exposition one of the sample was covered with the quartz window and the other sample was directly exposed to the plasma, afterwards the results were compared. The microbial abatement observed for the samples covered by quartz window was much lower than for the the samples directly exposed to the plasma. In first case the UV radiation and temperature is the main inactivation mechanism, while in the latter one the synergistic effect of UV radiation, temperature and active species is employed. Furthermore the effect of plasma sterilization increases with increasing the plasma exposition time. While comparing results observed for the argon and nitrogen, better results were achieved in argon. Effects of UV radiation and temperature were studied separately. The temperature between the DBD electrodes was measured by means of thermocouple. Afterwards the samples were placed in an oven and exposed to the same temperature as was measured between the electrodes. By comparing the results of heat treated samples and plasma treated samples it can be assumed that the influence of the temperature during the sterilization process in DBD was negligeable. The discharge parameters were studied by means of the optical emission spectroscopy.
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Design of Hydrogen Peroxide Disinfector
Makarová, Sylvia ; Rubínová, Dana (referee) ; Fridrichová, Eva (advisor)
The aim of this bachelor thesis is to design a hydrogen peroxide disinfector with regard to all its functional and technical parameters. Emphasis is placed simultaneously on the aesthetics of the product. The work is based on the analysis of accesible products and detailed technical analysis. The final device is intended primarily for medical facilities, but it can be used in any other areas, where is disinfection needed
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Proposal for a new system of continuous quality measurement pairs
Foltová, Anežka ; Sedlák, Petr (referee) ; Holcman, Vladimír (advisor)
This paper deals with proposal of new continual system for quality measurement of sterilization steam. At the begining the process of sterilization is introduced. Then the concept of saturated streams, parameters for sterilization and sensors for measurement are described. Then the current process of measurement of steam quality is described and in the last part the proposal of the new system is introduced. After the draft was the measurement data, analysis and evalution.
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Study of sterilization effect of diaphragm discharge in liquids
Holíková, Lenka ; Slámová, Jitka (referee) ; Kozáková, Zdenka (advisor)
The main objective of this thesis is to study the sterilizing effect of diaphragm discharge in liquids. Sterilization is a process, which can eliminate all forms of life. Generally, sterilization is divided into physical and chemical methods. Plasma sterilization is ranked among physical methods although the action of chemical processes participates in the decontamination as well. Effects of UV radiation, free radicals and temperature are utilized in these methods. Fungi spores of Aspergillus niger F8189 and bacteria spores of Bacillus subtilis are selected as model organisms. Aspergillus niger microorganism is suitable for its resistance to changes in pH and it is viable in a wide range of pH values. Bacillus subtilis is chosen because of a good heat resistance. Diaphragm discharge is one of the possible types of electrical discharges in generated liquids. It is a low-temperature plasma, which is generated using a high DC voltage. In the created plasma streamers various physical and chemical processes rise. The chemical processes are mainly the generation of active species and particles that initiate subsequent chemical reactions and attack mould spores and bacteria in liquids. The physical processes include shock waves, strong electric field and ultraviolet radiation. Experiments were conducted in a reactor with separate cathode and anode space. In the dielectric barrier PET diaphragm with a pin-hole (initial diameter of 0.4 mm) was attached. Enlargement of the hole was observed as a result of degradation of material at the edge of holes due to the discharge. Degradation of spores was observed, depending on the time and on the input power. Other parameters measured were pH, conductivity and temperature. Experiments did not show any difference of discharge activity in the cathode and anode area. The main factor in the removal of spores Aspergillus niger was probably the temperature because no demonstrable effect of sterilization by the diaphragm discharge operation had been observed when heat resistant Bacillus subtilis was used. Also, it was made an attempt, which has been studied only the temperature effect of the fungi spores of Aspergillus niger. The samples were placed in a thermoregulator, where it was simulated the same temperature increase as at the discharge. The experiment had a similar course as an attempt at the discharge.
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Physical properties of steam sterilization
Kotlánová, Markéta ; Sedlák, Petr (referee) ; Holcman, Vladimír (advisor)
The master’s thesis deals with finding, measurement and evaluation of suitable physical parameters for quality analysis of saturated steam sterilization according to ČSN EN 285 + A2, which is the first step for the replacement of outdated processes of the analysis by modern automation systems. The other part of the project contains description of physical sterilization, saturated steam, methods and sensors for the monitoring of steam sterilization and the measurement and evaluation of these issues.
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