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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Využití dálkového průzkumu Země pro zkoumání teplotních charakteristik povrchu / Temperature characteristics of surface using remote sensing methods

Hofrajtr, Martin January 2019 (has links)
Temperature characteristics of surface using remote sensing methods Abstract The aim of this thesis is to design a methodology for refining the land surface temperature values obtained from Landsat 8 satellite data in areas with diverse land cover. The research section describes factors influencing the radiation of the Earth's surface. Also mentioned are current methods used for processing infrared thermal data and calculate land surface temperature. The practical part describes satellite and airborne data used in the analytical and verification process. All parts of the applied method leading to the subpixel value of the land surface temperature are described in detail in the method part. The results are then compared with airborne verification data with better spatial resolution and with currently used methods. Finally, the pros and cons of this method and its possible improvement in the future are mentioned. Key words: land surface temperature, land surface emissivity, satellite data, Landsat 8, airborne data, subpixel method, Czech Republic
12

SELEKTIVNÍ EMITOR PRO TERMOFOTOVOLTAICKÉ SYSTÉMY / SELECTIVE EMITOR FOR THERMOPHOTOVOLTAIC SYSTEMS

Šimonová, Lucie January 2021 (has links)
The work is focused on research and development of a suitable method for creating a selective emitter for the visible and near infrared region so that they are able to work optimally together with silicon photovoltaic cells in a thermophotovoltaic system. The aim of the work was to develop a new method of creating very fine structures outside the current standard, which will increase the emissivity of the base material to meet the needs of a selective emitter for the VID and NIR region. The methods available to us for the creation of structures were chosen, from which we eliminated all unsuitable ones and we introduced the optimal procedure and parameters for their creation for the selected method. In this work, we focused on both ceramic and metallic materials, whose heat resistance and selective properties are key to this work. Part of the development of the emitter structures was also the need for pretreatment of the substrate itself, where great emphasis was placed on the purity of materials and surface roughness. Since ceramic materials cannot achieve a surface roughness so low that the desired structures can be formed, these materials have been purposefully used primarily for the purpose of combining the base material with thin layers of other high temperature material. Their compatibility and suitability were verified in terms of adhesion and subsequent heat resistance. The main material for the formation of fine structures was purposefully chosen tungsten, for which we verified the influence of the formed structure on the emissivity as well as the thermal stability during long-term exposure to high temperatures. The work thus represents not only a new method of creating very fine structures, which are not normally formed in such subtlety, but also opens the way to new possibilities of combining more materials to achieve the required selectivity of the thermophotovoltaic emitter.
13

Výpočtové postupy příčně obtékaného svazku trubek / Calculation methods for tube banks heat exchanger

Housírek, Jiří January 2012 (has links)
This diploma thesis deals with calculation methods of heat exchanger with cross-flow tube bundle. The first part of the thesis contains summary of generally known basic calculation relations used in calculations of heat exchangers and a detailed description of a given heat exchanger.The second part of the thesis provides a description of available calculation methods of a given aparatus required for its thermal and hydraulic calculation. The final part describes application POST in 1.0 which has been formed on the basis of these calculation methods. Using this application check calculation of exchanger with cross-flow tube bundle was carried out and gained figures compared with results gained by means of professional calculation program HTRI.
14

Emisivita a její vliv na odvod tepla / Emisivity and its Impact on the Heat Conductivity

Gančev, Jan January 2016 (has links)
This work deals with the issue of emissivity and its impact on the heat dissipation.The first part describes the basics of thermal management, the issue of emissivity and its measurement. In the second, experimental part, are dedicated the emissivity values of examined specimens. These values are then used as initial conditions for the thermal simulation. In the last part are compared the measured results and the simulated results and is evaluated the impact of emissivity for the heat dissipation.
15

Metody prostorové a spektrální charakterizace světelných zdrojů používaných v automobilové technice / Methods of Space and Spectral Characterization of Light Sources used in Car Industries

Guzej, Michal January 2018 (has links)
Automotive headlamps work in very variable operating conditions during which the producer have to guarantee their primary function of seeing and being seen. During the development stage of the new headlamps the manufacturers want to eliminate defects which could led to malfunction in operation. The numerical simulations along with the test procedures are appropriate tools for detection of problematic areas. The most appropriate approach is designing of experiment with a view to the subsequent simple implementation of the measured data into numerical simulations software and carefully choosing a measuring method of the monitored physical quantities. The thesis deals with phenomenon of condensation in headlamps, which has a negative effect on the light distribution and their life expectancy. Due to this experimental defog methodology was developed based on evaporation of a specified amount of water into the headlamp and then condensation on the inside surface of the headlamp lens. Pictures are taken during the measurements and the fogged and defogged areas are automatically detected. The results from experiments are used to adjust and verify a numerical model. The next part is devoted to the thermal load of the headlamp components which are mostly heated by waste heat from light sources. This phenomena depends mainly on the type of source, emissivity and thermal conductivity. A methodology of temperature measurement, thermal conductivity measurement, non-stationary method for emissivity determination and spectral characterization of thermal source based on their thermal fluxes to the surroundings has been developed.
16

Měření teplotních polí v elektrických strojích / Measurement of thermal field in electric machines

Dostálek, Martin January 2010 (has links)
Diagnosis temperature is one of the most important disciplines. We meet it in everyday life, but it is very important for all sectors of industry. This is a measurement providing an immediate state of the measured object. Contact measurement of different temperature sensors and contactless measurement using thermal imagers. The important part is the measurement of temperature rise of induction motor. Part of the work deals with losses in the electric motor. These losses are converted into heat, which affects from various parts of the machine. Correct identification of the temperature field is important in helping to design the cooling system of the instrument. Virtually the data obtained are compared with theoretical data. We will capture part of the device and realize thermal simulations in a suitable simulation program. We propose modifying the cooling machine and the resulting data from the simulation compares.
17

IR teploměr s automatickou korekcí emisivity / IR thermometer with automatic emissivity correction

Dobesch, Aleš January 2013 (has links)
Diploma thesis deals with basic physical quantities and laws relating to non-contact temperature measurement and emissivity determination of solids. It describes the design and implementation of the IR (Infra-Red) thermometer often missed with automatic emissivity correction. The first chapter explains the concept of temperature and basic principles of temperature measuring . The second chapter focuses on the history and theory of non-contact temperature measurement. Gradually are explained the concepts related to non-contact temperature measurement and the problem of determining the emissivity of the body. Next third chapter describes the proposed hardware solution of IR thermometer. The fourth chapter describes a software written for the IR thermometer. The fifth and last chapter summarizes the findings and knowledge from the implementation of non-contact thermometer and measuring emissivity.
18

Termodiagnostika - dotykové a bezdotykové měření teploty / Thermodiagnostics – contact and contact-free temperature measurements

Mikula, Martin January 2014 (has links)
This thesis is concerned with thermodiagnostics in industrial practise, which is very important for the assessment of technical condition of object on the basis of temperature, in today's time. It includes summary of contact and contact-free methods and their principle, advantages and disadvantages for aplication in industrial practise. Because of thesis it was carried out measurement in company Daikin Device Czech republic with the use of contact thermometer and two available thermocameras for solving of topical tasks relating to production.
19

Zařízení pro měření tepelného odporu rukavic / Apparatus for measuring the thermal resistance of the gloves

Pelikán, Jakub January 2016 (has links)
This thesis deals with common problem health protection at work. Namely hand protection during the work in very cold environment. It’s an analysis of materials suitable for apparatus used for measuring the thermal resistance of the gloves. There was analysed a range of materials. Every single sample was tested for heat conductivity and afterwards was assessed the suitability of materials. Heat was generated by electricity. Ocured heat fields was assessed with thermocamera. After performed experiments of carbon fiber we haven’t reached any satisfying results which we could use for manufacturing of this device. On the other hand kapton film has given very interesting results which we would recommend eventually. Kapton film needs to be modify according to the method listed in the conlusion. This thesis gives us a clear overview and inspiration for additional research of this device. It finds it’s place in research facilities and companies manufacturing protective clothing.
20

Vytápění bytového domu / Heating of flat house

Zajíček, Václav January 2019 (has links)
The thesis is composed of three parts - theoretical, computational and a project part. The theoretical part deals with heat sharing through conduction, flow and radiation. The computational part is focused on the overall calculation of the heating system to operate smoothly and reliably. Three gas condensing boilers are designed as a source of heat. The heating of the water is solved as a reservoir. It's source of heat is one gas condensation boiler. The project part contains a technical report and the project documentation on the stage of the implementation dossier.

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