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SMV-2023-42: Materials for thermal management
Králík, Tomáš
This contract research dealt with so-called solar white coatings with a very different ability to absorb visible radiation and emit thermal radiation. We have studied special coatings designed for the space environment with high emissivity in the field of thermal radiation and at the same time low absorption of radiation originating from the sun or reflected from cosmic bodies. This type of coating is intended for passive thermoregulation of parts of apparatus moving in the space environment. The aim was to determine the so-called total hemispheric emissivity of each of the samples at the required temperatures. For these coatings, the client's goal was also to evaluate the effect of the morphology of the sample on the resulting emission of thermal radiation. Namely, we tested the flat and pyramidal structured surface of the base material. This unique research required a special modification of the supplied samples, modification of the dedicated method for measuring emissivity and absorptivity at cryogenic temperatures, as well as a new procedure for calibration and evaluation of the received data. We used a previously developed shielding ring around the perimeter of the samples to cover the perimeter of the structured samples, which prevented part of the measured thermal radiation from escaping. The results of this research will be used in the design of the CO2M space mission for monitoring CO2 emissions.
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SMV-2023-41: Absorptive coatings for quantum computers
Králík, Tomáš
This contract research focused on the thermal analysis of absorptive layers created by anodic oxidation on aluminium alloy, which are optimized for use at extremely low temperatures. These specific layers were designed for the low-temperature parts of quantum computers, where they play a key role in eliminating the reflection of thermal radiation from the hotter areas of the computer cryostat to the ultra-low temperature areas. Other key requirements for these absorptive layers are high thermal conductivity, necessary for efficient heat transfer within a quantum computer, good mechanical stability and extremely low outgassing to ensure long-term functional behaviour of the layers in challenging low-temperature conditions. The goal of this research was not only to verify the total hemispheric emissivity of three specific types of coatings in the temperature range from 10 K to 300 K. In this case, emissivity is a suitable indicator of the thermal absorptive behaviour of the layer. A study of the emissivity of these layers in the entire spectrum of temperature conditions relevant for quantum computers was carried out. This extensive analysis was intended to provide an insight into the suitability of these absorptive layers for applications in the field of low-temperature technologies, with an emphasis on the requirements of quantum computers.
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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-2023-38: Testing of surfaces for cryogenics
Frolec, Jiří
The ordering party required an analysis of the thermal-radiative characteristics of several different metallic materials, from which several special samples were designed and manufactured in cooperation with ISI Brno. These were tested in a special low-temperature apparatus. As part of the contract research, the relative rate of thermal radiation emission, the so-called total hemispheric emissivity, was determined at temperatures ranging from -268 °C up to room temperature. By comparing the results with each other, the client will be able to determine the optimal variant for the intended application, both in terms of the material itself as well as the applied surface finish.
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Thermal radiation in real life
Kalus, Petr ; Zálešák, Martin (referee) ; Klimeš, Lubomír (advisor)
This bachelor's thesis deals with the impact of heat transfer by radiation on the life around us. The research part summarizes the fundamental laws and concepts necessary for understanding the given issue. Furthermore, it describes and analyzes phenomena in everyday life where radiation is dominant. The greatest attention has been devoted to solar radiation, followed by the greenhouse effect, along with its influence on global warming. The thesis also includes a procedure for calculating heat transfer by radiation between two surfaces, based on which a Python script was written. Subsequently, a standalone application with a graphical interface was developed. The conclusion of the thesis focuses on describing the software development process and provides examples of test cases in thermomechanics.
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SMV-2022-43: Absorptivity and emissivity of materials for use in space
Králík, Tomáš
This contractual research was aimed at verifying the thermal radiation properties of the emissivity of coatings and covering foils for space probes. Half of the experiments were focused on thermal regulation coatings, the purpose of which is to passively maintain the optimal temperature of the device, the balance between thermal radiation and absorption of visible radiation. Some foils had unique thermochromic properties, where their thermal radiative properties change sharply with their own temperature. The second part of the research was focused on the effect of contamination of a clean metal surface with dust simulating lunar regolith on the absorption of thermal radiation. As part of this research, five differently contaminated surfaces were measured. This unique data will enable the contractor to better design apparatus for work on the surface of the Moon or other planets. The contractor selected and supplied\nsamples of materials in the form of foils and coated sheets, which had to be modified into a sample suitable for the apparatus operated at the ISI Brno. A material labelled EAC‐1A was used as a lunar regolith simulant. The goal of the project was to evaluate the so‐called total hemispheric emissivity or absorptivity in the temperature range from 20 K to 300 K.
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SMV-2022-42: Emissivity of coatings for space mission ARIEL
Králík, Tomáš
This contractual research was aimed at verifying the thermal emissivity of materials planned for use in the optical system of the ARIEL infrared telescope located in orbit around the earth. The contractor selected several samples of the coating with high light absorption. However, the thermal radiation properties of this coating were not yet known. The goal of the project was to evaluate the so-called total hemispheric emissivity in the temperature range from 20 K to 300 K. The results will enable the customer to model the temperature distribution inside the optical path of the telescope.
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SMV-2022-09: Special coatings for a radio-frequency absorber
Frolec, Jiří
As part of the upcoming mission of the European Space Agency, the space-probe JUICE, the task of the Max Planck Institute for Solar System Research is to determine the thermal radiation properties of the coatings intended for the radio-frequency absorber of this probe. In frame of this project, there was an experimental verification of the relative rate of thermal radiation emission, so-called emissivity, of two different coatings deposited on the surface of the developed samples. The main output of the research is the low-temperature tests of these samples carried out using a unique measuring apparatus, cooled by a bath of liquid helium. The emissivity of thermal radiation of both surfaces was determined in the temperature range from 20 K to 300 K. As part of the project, we also assessed, in addition to the thermal-radiative properties, the mechanical stability of the sample at low temperatures. All data have been submitted to the Max Planck Institute in the form of research reports.
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SMV-2022-08: Methods of thermal radiation measurements
Frolec, Jiří
The research activity was focused on experimental methods for testing the relative rate of materials to emit or absorb thermal radiation, i. e. emissivity and absorptivity. The main output is a review of available methods, with an emphasis on those operated at low temperatures. The ordering party's goal is to build dedicated workplace capable of performing the mentioned type of measurements. For this purpose, it was necessary to create an overview of the methods and assess the optimal one for the given purpose. The required research was carried out by members of the Group of Cryogenics and Superconductivity from ISI Brno, based on the available literature as well as on theoretical and practical experience gained during two decades of experiments with their own cryogenic apparatus for measuring thermal radiation interacting with various materials.
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SMV-2022-07: Cryogenic tests of aluminium foils with low emission and absorption of thermal radiation
Frolec, Jiří
The research was focused on the heat transfer by thermal radiation, specifically the interaction of thermal radiation with several different types of aluminium foils, used mainly in the so-called multilayer insulation (MLI). From the supplied raw material, samples suitable for testing were fabricated at the ISI Brno and then examined according to the requirements of the company. We focused on the temperature dependence of the relative ability of the samples to emit or absorb thermal radiation at all wavelengths and in all directions. The experimental verification then took place in a dedicated apparatus cooled by a liquid helium bath for a temperature range from about -253 °C to room temperature, which required choosing an optimal configuration of the apparatus and verifying its calibration. After the individual measurements, the received data were processed, the temperature stability of the foils at low temperatures was evaluated and their thermal-radiation properties were compared with our own low-temperature database of cryogenic measurements. The project contributed to selection of the optimal foil for the intended application, i. e. for use in MLI.
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