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Methods of Space and Spectral Characterization of Light Sources used in Car Industries
Guzej, Michal ; Černý,, Pavel (referee) ; Samek, František (referee) ; Horský, Jaroslav (advisor)
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.
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Methods of Space and Spectral Characterization of Light Sources used in Car Industries
Guzej, Michal ; Černý,, Pavel (referee) ; Samek, František (referee) ; Horský, Jaroslav (advisor)
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.
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Statistical Analysis of Temperature and Precipitation Time Series in the Czech Republic in Period 1961-2008
Helman, Karel ; Pecáková, Iva (advisor) ; Čermák, Václav (referee) ; Žák, Michal (referee)
The present dissertation deals with an analysis of monthly time series of average temperatures and precipitation sums recorded at 44 sites in the Czech Republic over the period of 1961--2008. The main research purpose is to acquire deeper knowledge of regularities in the climatic time series development, using an appropriate set of statistical methods. A secondary objective is to search and find correlations between the research outcomes and basic geographic coordinates (altitude, longitude and latitude) of particular measurement stations and comparing all the results achieved for the selected climatic elements. There are two major contributions of this work. In the first place, it presents new knowledge in the field of climatic time series, particularly in connection with the strength and development of their seasonal component, further for instance analysing the relation between the distribution of a residual component and the geographic coordinates of the measurement stations. Another contribution lies in an extensive application of statistical methods of climatic time series analysis. Several types of methods were used, having employed both widely and rarely applied statistical tools (linear trends analysis and Box-Jenkins methodology respectively) as well as those used for the very first time (moving-seasonal time series).
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