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Power measurement in ultrasound fields
Škůrek, Pavel ; Čížek, Martin (referee) ; Rozman, Jiří (advisor)
This work is focused on the developement of a sensor, which enables to measure the ultrasonic power by heat effect of the mechanical Wales. The princip of two basic kinds of thermoacoustic sensor is descibed here – one level and two level sensor. This work also contains a proposition of these sensors with description of each parts and a trial to find suitable absorber. Achieved results, which support the function of the sensors are presented here by form of graphs and tables. Measuring by thermoacoustic sensors is confronted here with measuring of ultrasonic by hydrophone, which is used as reference measuring.
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Power measurement in ultrasound fields
Škůrek, Pavel ; Čížek, Martin (referee) ; Rozman, Jiří (advisor)
This work is focused on the developement of a sensor, which enables to measure the ultrasonic power by heat effect of the mechanical Wales. The princip of two basic kinds of thermoacoustic sensor is descibed here – one level and two level sensor. This work also contains a proposition of these sensors with description of each parts and a trial to find suitable absorber. Achieved results, which support the function of the sensors are presented here by form of graphs and tables. Measuring by thermoacoustic sensors is confronted here with measuring of ultrasonic by hydrophone, which is used as reference measuring.
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The increase of the air temperatures observed in different European localities during 1951-2010
Střeštík, Jaroslav
Uninterrupted series of annual mean temperatures from 72 European observatories have been processed. The temperature at these stations increased in general more than global temperature, but with considerable fluctuations. The increase at the individual stations is very different. It depends very slightly on the geographic longitude. Stations where lower temperature increase has been observed are located mainly at the Atlantic coast, those with higher increase being mainly in inland. There are, however, many exceptions from this rule, but the gross character of the distribution of stations with different temperature increase seems to be clear.
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The change of mean air temperatures i the town and outside the town during the last 65 years
Střeštík, Jaroslav
The climate in the town differs from that in the nearest surroundings in many respects: in the town higher air temperature. lower air humidity, much higher air pollution et. takes place. The town can be considered as an island with a different environment. Due to the increase of towns all mentioned differences between the town and its surroundings increase too. In this contribution the change of mean annual, and seasonal air temperature in the Prgue center (Klementinum) and on its boundary (airport Ruzyně) during 1946-2009, partly on airports Tuřany and Mošnov during 1951-2009, will be presented. Mean air temperatures on all stations display, besides a considerable fluctuation, a stable increase given by the global warming.
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