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Plasmachemical deposition and characterization of hexamethyldiloxane thin layers
Blahová, Lucie ; doc. Mgr. Vít Kudrle. Ph.D. (referee) ; Krčma, František (advisor)
Thin films have been used to modify surface properties of various materials for many years. Plasma Enhanced Chemical Vapor Deposition (PECVD) is one of the possible methods for their preparation and this technique is applied in this work as well. An organosilicone – hexamethyldisiloxane – is used as precursor. Thin films are created on the surface of the substrate using mixture of precursor and oxygen in radiofrequently excited capacitively coupled plasma. The aim of the thesis is to find the optimal deposition conditions for production of transparent thin layers with good barrier capabilities, low oxygen transmission rate especially. Thin film depositions were realized for different compositions of the deposition mixture in continuous and pulsed mode of plasma with varying supplied power and duty cycle values. The deposition process itself was monitored in situ by optical emission spectroscopy. Thin film coatings were analyzed to determine their physical chemical properties (infrared spectroscopy, surface energy) and barrier properties. Using optical emission spectroscopy, important particles were identified in the deposition plasma. Vibrational, rotational and electron temperatures were determined from relative intensities of chosen fragments. Composition of thin films was studied by infrared spectroscopy. The best results of oxygen transmission rate were achieved with layers prepared from deposition mixture with high oxygen content. It was possible to improve barrier properties by performing deposition in pulsed plasma mode with 20–30% duty cycle. In this diploma thesis, optimal deposition conditions of thin films from hexamethyldisiloxane with low oxygen transmission rate were determined. It is possible to use these results in practical applications, such as corrosion inhibitors for archaeological objects. Optionally, they can be used in various industry branches where it is desirable and feasible to prevent oxygen access to the material by deposition of barrier coatings.
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Generation of metallic nanoparticles by non-thermal plasma in liquids
Čechová, Ludmila ; Blahová, Lucie (referee) ; Kozáková, Zdenka (advisor)
This thesis focuses on the process of nanoparticle generation using new source of nonthermal plasma combining corona and pin-hole discharge in liquids. The theoretical part is focused on generation of metallic nanoparticles using various types of plasma discharge, the properties of metallic nanoparticles, their preparation by other methods and methods of characterization of nanoparticles. The experimental part deals with the preparation of copper, silver and gold nanoparticles from solutions of their precursors. The influence of experimental conditions, such as the influence of voltage polarity, effect of precursor concentration, effect of added electrolyte or reducing agent were investigated. All samples were analyzed by UV-VIS spectroscopy. Dynamic light scattering was used to determine the sice of nanoparticles. To confirm the presence of nanoparticles, samples were analyzed using scanning microscope with and energy dispersion spectrometer for elemental analysis.
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Preparation and characterization of thin barrier layers
Blahová, Lucie ; Mráček, Aleš (referee) ; Buršíková, Vilma (referee) ; Krčma, František (advisor)
Combinations of different acrylic resins and microcrystalline waxes are most often used for the conservation and preservation of metallic archaeological artefacts these days. However, their properties are not sufficient and satisfactory in many ways. Therefore, the aim of this doctoral thesis is to develop a conservation system which will draw on the new knowledge gained in the field of advanced materials and technologies during last years. A conservation coating based on a thin barrier film appears the most promising. The conservation coating must fulfil particularly following rather contradictory requirements: good barrier function against oxygen, humidity and other corrosive agents; transparency because of colour appearance preservation; long term stability and easy removability; possibility to apply to more objects at the same time and reasonable financial requirements of a deposition process. Parylene C polymer was chosen as suitable material for this purpose. It was prepared via modified chemical vapour deposition. Parylene removability was ensured through the soluble interlayer made of Laksil silicone-acrylic lacquer which was applied between the protected metallic object and the parylene thin film. Initially, the deposition process of Laksil/parylene bilayer was optimized, then its physical and chemical characteristics were determined and eventually, they were compared with the conventional conservation coating composed of Paraloid B72 acrylic resin and Revax microcrystalline wax. Regarding to the demands of the conservation coating, we were interested especially in barrier properties, optical properties, surface morphology and removability of Laksil/parylene bilayer. The most useful method for description of coating barrier properties was corrosion testing in which coated metallic samples were exposed to highly corrosive environment of salt spray (made of 50 g•l–1 brine), 100% humidity and temperature of 35 °C (ISO 9227). The Laksil/parylene bilayer showed excellent barrier properties; samples treated this way sustained unchanged in the corrosion chamber for almost three months. The surface roughness measured by profilometry and surface morphology scanned by SEM illustrated the synergy between Laksil and parylene layer which leads to the exceptional barrier and anticorrosion function of bilayer. The Laksil layer is able to flatten out rough surface of a substrate. Furthermore, it can toughen the item surface which is, in case of a number of archaeological findings, created by corrosion product layers with variable mechanical strength. Thereon deposited parylene film becomes smooth and defect free and can act as a good diffusion barrier. The colouristic measurements confirmed that the Laksil/parylene bilayer does not almost change the appearance of protected item, in terms of colour. The caused colour difference (ISO 11664-4) ranged around 1 which value is defined as “perceivable only for experienced observers”. The Laksil/parylene bilayer is removable thanks to the Laksil solubility in xylene. It is necessary to carefully scratch the outer parylene film to enable access of xylene solvent to the lacquer. The successful removal of Laksil/parylene bilayer was first confirmed by the EDX on metallic iron samples. Afterwards, the possibility of bilayer complete removal even from a corroded surface of the original artefact was proved by TGA. Thus the conservation treatment can be considered fully reversible.
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Generation of ozone by photochemical processes in O2 and admixtures
Tomečková, Klára ; Blahová, Lucie (referee) ; Mazánková, Věra (advisor)
Ozone is a toxic gas with the fatal impact to living organisms at high concentrations. Therefore, this gas is useful in sterilization in many cases. The subject of this work is the generation of ozone using various methods and determination of its concentration. Then the generated ozone can be used in ozone therapy. The theoretical part deals with properties and use of ozone. In addition, information gathering connected to ozone was performed. It was about methods of ozone generation and subsequently about the diagnostics determine of ozone concentration. In the experimental part the ozone generation and determination of its concentration was performed using spectrophotometric method and iodometric titration. The ozone concentration in the air was also measured over the long term using the Schönbein method.
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Characterization of plasma during organosilicone thin film deposition using haxamethyldisiloxane monomer
Blahová, Lucie ; Mazánková, Věra (referee) ; Krčma, František (advisor)
The aim of this thesis is plasma diagnostic during deposition of thin films based on organosilicones. Hexamethyldisiloxane was used as a precursor for plasma deposition in the presence of oxygen, and the diagnosis was performed by using optical emission spectroscopy. The theoretical part summarizes the basic characteristics of plasma and processes occurred at plasma polymerization and deposition. It also deals with thin films and their use in coating materials. A relatively large part is devoted to the specification of the physical-chemical nature of the used analytical method – optical emission spectroscopy. Finally, the principles of rotational, vibrational and electron temperature calculations are described. The contemporary deposition process was carried out in continuous and pulsed mode of radiofrequently excited capacitively coupled discharge. The effects of monomer flow rate, plasma power and duty cycle on the deposition process were studied. In the individual spectra, atomic hydrogen lines of Balmer’s series as well as an atomic oxygen line were identified. Molecular bands of CO have been identified as Angstrom’s system and 3. positive system. In the case of the identified fragments, the intensity dependencies on the monomer concentration in mixture, plasma power and duty cycle were detected. Electron temperature of plasma was also calculated using the relative intensities of atomic hydrogen lines of Balmer’s series. Vibrational and rotational temperature could not have been determined because no suitable fragments for their determination were found in the spectrum. Based on findings mentioned above, partial composition of plasma and some of its properties were estimated. The subject of the further research will be determination of the exact content and structure of the thin films and investigation of other plasma characteristics. Plasma deposition is influenced by many factors, and the study of their optimal combination for the most efficient deposition process is a goal for the future research.
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Evaluation of the Enterprise Performance According to the START Model and Tips for Progress
Bláhová, Lucie ; Chalupa, Michael (referee) ; Luňáček, Jiří (advisor)
This bachelor thesis focuses on the performance evaluation of a selected company using the START Model. The theoretical part defines the basic concepts and methods related to the measurement of company performance by using multi-criteria models. The analytical part deals with the evaluation of the current situation and the subsequent identification of strengths and opportunities for improvement. Based on the outputs of the non-financial analysis, the design part proposes measures to improve the performance of the selected company.
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Developing tradition or From exposition to interpretation: Methodology of guide services in historic interiors and exteriors
Jareš, Jakub ; Hudec, Petr ; Indrová, Martina ; Ranochová, Radka ; Hnojská, Vendula ; Sládková, Kateřina ; Jordánová, Květa ; Dryáková, Kateřina ; Rezková Přibylová, Naděžda ; Bláhová, Lucie ; Wizovský, Tomáš
The methodology provides methodological support and inspiration for the presentation and interpretation of cultural heritage through guided guided tours. It takes into account both tradition and the current demands of visitors, approaches to the protection of cultural heritage and new trends in interpretation, including foreign ones. When applied in practice, the methodology also has an impact on the general public, which is represented by several million visitors to the monuments managed by the NPÚ every year.
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Many forms of interpretation: Methodology of innovative approaches to the presentation and interpretation of historic interiors and exteriors
Hudec, Petr ; Jareš, Jakub ; Indrová, Martina ; Dryáková, Kateřina ; Kassl, Nikola ; Havlůjová, Hana ; Hnojská, Vendula ; Sládková, Kateřina ; Jordánová, Květa ; Rezková Přibylová, Naděžda ; Kazlauskas, Vendula ; Bláhová, Lucie ; Staufčíková, Helena ; Kosová, Šárka ; Neprašová, Eva ; Seidler, Tomáš
The methodology is an effort to revitalize and innovate the guide service in the environment of historical monuments under the administration of the National Museum of Natural History. This publication is a follow-up to Part I of the methodology We are developing tradition or From interpretation to interpretation and its purpose is to provide ideas, inspiration and methodological procedures on how to supplement and transform established methods of presentation and interpretation of monuments, including forms that create a parallel or alternative to guided tours . It takes into account foreign experience and interdisciplinary insights.
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Recruitment and staff selection
Bláhová, Lucie ; Kocianová, Renata (advisor) ; Pivoňková, Lucie (referee)
Recruitment and staff selection is a topic which deserves attention to be given in literature. Recruitment and staff selection are areas of personnel work that are crucial for any organization because they influence its efficiency. The fundamental part of successful selection process is job analysis which is followed by recruitment. Every organization should consider choosing recruiting from internal (inner) sources or recruiting from external (outer) sources, or its combination. Another issue that an organization should consider is the method or methods of recruitment. Staff selection is not less important than recruitment and there are more methods of staff selection as well. Regarding both methods of recruitment and methods of staff selection, organization usually chooses more than one method of recruitment and more methods of staff selection at the same time. In the practical part of my thesis I concentrated on AYS and its service portfolio. I focussed my attention on ways of recruitment and the process of selection. AYS uses well-established means of recruitment such as on-line recruitment, advertisements and its own database of applicants. The whole selection process is executed according to the company's procedure and its know-how. I also tried to point out both weaknesses and strengths of AYS. There...
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Ecological validity research of Attention test
Bláhová, Lucie ; Preiss, Marek (advisor) ; Rendl, Miroslav (referee)
This bachelor thesis focuses on the issue of attention research, mainly from the neuropsychological point of view. It is an empirical study divided into two parts: The first theoretical part introduces the history of attention research, defines attention and presents the current theories of attention: Broadbent's Filter model, The Feature-Integration theory from Anne Treisman, David LaBerge's theory and Michael Posner's concept of attention. The second part of the work, the empirical part, is based on the discussed concept of attention, mainly from neuropsychologist Michael Posner. The purpose of the research study is to explore the ecological validity of Michael Posner's attention test - Attention network test (ANT). The following questionnaires were chosen as the methods for measuring the real-life attention: CFQ (Cognitive failure questionnaire), EMQ (Everyday memory questionnaire) and DEX (Dysexecutive questionnaire). The results of the study did not confirm the significant statistical correlation between results in Attention Network Test and scores in self-reported questionnaires, but the bachelor thesis' contribution's to ecological validity research can still be seen. KEYWORDS: Attention, Attention research, Ecological validity, ANT, Cognitive failure
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