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Effect of gold coating on emissivity and absorptivity of Ti-6Al-4V alloy
Frolec, Jiří ; Králík, Tomáš ; Musilová, Věra ; Urban, Pavel
The article provides experimental analysis of total hemispherical emissivity and absorptivity of Ti-6Al-4V alloy before and after deposition of 1-2 .pí.m gold layer. We measured their dependences on the temperature of thermal radiation (varying from 20 K to 320 K) and confronted these results with mechanically polished copper, i.e. with material known for extremely low emissivity and absorptivity. Galvanic deposition of pure gold resulted in significant lowering of original emissivity of Ti-6Al-4V bare surfaces from 15.8 percent to 3.4 percent at 300 K and from 4.1 percent to 1.1 percent at 20 K. Our findings about thermal-radiative properties have practical relevance for an improvement of a low temperature part of an ultra-high vacuum scanning probe microscope\n(UHV-SPM) designed by our group and could also be useful for other applications and low temperature systems.
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SMV-2016-16: Emission and absorption of the thermal radiation of metallic materials for space crafts
Králík, Tomáš
The goal of the experimental study was verification of the radiative heat exchange by emission or absorption of the thermal radiation of materials for parts of a future meteorological satellite. The samples were coated by a protective metallic layer by a magnetron sputtering. It is supposed that this coating substantially decreases the emission of a thermal radiation in comparison with the bare alloy. Within the study were verified also the thermal radiative properties of samples made of bare sandblasted alloy, samples with the protective coating and samples treated by anodic oxidation. The thermal radiative properties were measured in high vacuum with sample temperatures in the range from 25 K to 320 K.
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SMV-2016-17: Thermal radiative properties of solar coatings and spacers for multilayer insulations
Králík, Tomáš
The experimental study was about evaluation of thermal radiation of special coatings used against excessive warming by solar radiation. A part of this study was aimed on thermal properties of spacers for multilayer insulations where the heat is transferred by combination of the thermal conduction and radiation. All the measurements were done in the vacuum and in the temperature range from 10 K and 300 K at conditions simulating real environment of the usage of the materials.
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Design of Medical Thermal Imaging Camera
Vespalec, Arnošt ; Haltof, Vladimír (referee) ; Rubínová, Dana (advisor)
The aim of this thesis bachelor is the design of the medical thermal imaging camera, which will be its solution respecting technical, ergonomic and economic requirements. Among other things, it includes an overview of the current market situation, with an emphasis on the development of new technologies, including experimental.
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SMV-2015-18: Radiative heat losses in the temperature range from 30 K to 335 K of metallic coatings with various surface treatments including simulation of cleaning on the structural materials for satellites
Králík, Tomáš
Research and development in the field of heat transfer by thermal radiation. The object of the research was verification of heat loses by the thermal radiation from surfaces of materials used for construction of satellites. The samples of the material were coated with metallic film with substantially lower emission of the thermal radiation than of the structural material. This coating was created with variation of the parameters and a cleaning process was simulated on some samples. The emission of the of the thermal radiation was measured with temperature of the sample in the range from 30 to 335 K. The measurement procedure was adapted for some samples because of the lower limit 200 K due to possible delamination of the coating. The study has verified stability of the requested thermal radiative properties of the protective metallic layer with respect to the variation of its production and subsequent cleaning process.
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SMV-2013-27: Thermal radiation absorptivity for development of multilayer insulation for alternating electromagnetic fields
Králík, Tomáš ; Hanzelka, Pavel
Super insulations composed of many layers of metalized plastic foils are one of the ways of significant heat flow reduction to low temperature parts of the apparatus. The metal layer was modified to reduce heat generation by alternating electromagnetic fields (e.g. in superconducting motors, generators or transformers). The modifications of the metallisation always worsen the thermal radiative properties of the foils and it was needed to evaluate its influence. The absorptivity of thermal radiation was evaluated in the experimental study on two foils coated with metallic film divided in segments and on the foil coated with metallic particles dispersed in a binder.
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Černé povrchy pro použití v kryotechnice
Králík, Tomáš ; Hanzelka, Pavel ; Musilová, Věra ; Srnka, Aleš
Surfaces with high absorption or emission of thermal radiation are often needed in cryogenic and space applications. It is more difficult to realize a sufficiently black surface applicable in cryogenic systems than to make highly reflective surfaces. Experimental results on black surfaces like epoxy coatings, paints and thin films concerning the thermal radiative properties (emissivity and absorptivity) in the temperature range from 20 K to 300 K of the source of the thermal radiation are presented.
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