National Repository of Grey Literature 110 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Clarinet in the production of the Czech classicist composers".
HOVORKA, Jan
This diploma paper is focused on clarinet music written by Czech composers of the classicist period, including anonymous compositions, which were preserved on the Czech territory. It pays attention both to solo concertos, as well as the chamber music. It is concerned also with the historical development of clarinet and its most important moments. The aim of this thesis is to provide some less known information about various compositions in a comprehensible way.
PM2.5 concentration field in the air of Zadni Treban village during heating season
Wallenfelsová, Karolína ; Hovorka, Jan (advisor) ; Mareš, Petr (referee)
This bachelor thesis evaluates the impact of local heating on PM2,5 concentrations mo- nitored in a village Zadní Třebaň in Central Bohemia between 21. 12. 2021 and 3. 2. 2022. It also examines the effect wind speed and temperature have on the PM2,5 concentrations. The PM2,5 concentrations were measured using both stationary and mobile monitoring. For the stationary monitoring, 7 DustTrak 8520 monitors (integration time 1 min) were used. A network of these monitors was built to cover different settlement (village edge, village center) as well as geological types of locations (valley, hill). The mobile monitoring took place 31. 1. 2022 over the course of 7 walks during which PM2,5 and PNC concentration were measured. Portable monitors were used for mobile mea- surements - DustTrak DRX for measuring PM2,5 concentrations and P-Trak for measuring particle number concentrations (PNC). The integration time for both of these monitors was 1 s. The aim of the mobile monitoring was to supplement knowledge gained from the stationary monitoring. The highest average 24h PM2,5 concentrations were measured on the 22. and 23. 12. 2021. On the 22nd the US EPA limit of 35 µg · m−3 was exceeded on almost all measuring sites except Stations 4 and 7. On the 23rd the limit was exceeded on all measuring sites except...
PM2.5 field in the air of Družec village during heating season
Šmok, Dominik ; Hovorka, Jan (advisor) ; Kozáková, Jana (referee)
Residential heating by solid fuel combustion in small settlements has great potential to degrade air quality, especially PM2.5 emissions, during the winter heating season, to such an extent, that WHO and US-EPA limits for PM2.5 are frequently exceeded. There were found significant temporal variability and spatial heterogeneity of the PM2.5 concentration field. 24h limit for PM2.5 (US-EPA, 35 μg∙m-3) using a stationary network of 6 monitors measuring minute concentration of PM2.5, In the village Družec, Kladno district, during the 14-day measuring campaign. Campaign average exceeded the limit at the primary school garden. In the other sites, the limit was usually exceeded occasionally except one day, when the limit exceedance was recorded in all the sites as well at the whole area of the Czech Republic. The analysis of time course of minute values of PM2.5 shows that the residential heating increased PM2.5 concentrations on average by 61-72% (16-25 g∙m-3) or 40-49% (6-10 g∙m-3) at exposed or background sites respectively; PM2.5 values decreased exponentially with wind speed up to 2 m∙s-1, when they stabilized at 8-16 g∙m-3. At the microscale of the village, there were also found spatial and temporal heterogeneity of PM2.5 and aerosol particle concentrations PNC using by mobile measurement of PNC...
Role of aerosol in climate change
Švátora, Milan ; Hůnová, Iva (advisor) ; Hovorka, Jan (referee)
Atmospheric aerosol is a suspension of liquid or solid particles or their mixture in the atmosphere. Tropospheric aerosols can get into the air from its natural sources or from anthropogenic sources. Release of carbon dioxide from burning fossil fuels and organic and elemental carbon from biomass burning are the major anthropogenic sources of aerosols. Primary aerosols have a direct source of emissions (dust from quarries or from land, sea salt particles in the waves, volcanic ash during volcanic eruptions). Secondary aerosols are formed by chemical reactions of substances in the atmosphere, which converts the gas particles - so- called conversion of gases to particles (formation of nitrates by oxidation of nitrogen oxides and sulfates from sulfur dioxide). Atmospheric aerosol is an important component of the atmosphere and contributes to significant atmospheric events, such as precipitation formation and precipation fall, radiation balance of Earth. Aerosols can affect the radiation balance of the Earth in two ways. First, through absorption and scattering of shortwave and long wave radiation - so-called direct effect. Or serve as condensation nuclei on which water is condenses. Aerosols can affect formation, quantity, length of existence and radiation properties of clouds - so-called indirect effect. In...
The impact of building isolation on CO2 concentration in flats
Čejková, Eliška ; Hovorka, Jan (advisor) ; Holcátová, Ivana (referee)
1 ABSTRACT This diploma work investigates the influence of thermal insolation at residential buildings on the concentration of CO2 (carbon dioxide) in indoor environment. The studied area is a housing estate of panel buildings (flats) in Sezimovo Ústí city. The present work notices a positive impact of thermal insolation on energy demands of buildings and it is mainly saving consumed heat energy which is also connected with emission lowering of carbon dioxide emissions. The main problem which is soluted in the work is that total insolation is usually done without any ventilation solution. It means that it has later a negative impact on indoor environment/air quality in flats. The main part if this work presents measurements of indoor air quality - CO2 concentration, air change rate, temperature and relative humidity in an insolated (with plastic windows) and a non-insolated (with the original wooden windows) flats. The measurement lasted for three days in selected pairs of flats - with plastic and wooden windows. The measuremet took place in bedrooms because the behaviour of residents of households was very similar during their sleep. The air change rate was then caculated from CO2 concentration decay during period of 3 hours without residents. The main aim is to quantify these differences. The conclusion...
Study of aerosol properties with high time resolution
Kubelová, Lucie ; Ždímal, Vladimír (advisor) ; Hovorka, Jan (referee) ; Vojtíšek, Michal (referee)
This thesis focuses on physical and chemical characteristics of atmospheric aerosol measured with high time resolution. Size distribution, chemical composition, and volatility of submicron particles were studied in relation to meteorological conditions and other factors. To reach higher variability in ambient conditions, we considered atmospheric aerosol during two seasons of the year (summer and winter) and at two different locations (suburban site Prague Suchdol and rural site Košetice). Measurement during two different seasons enabled us to better distinguish the influence of seasonal sources such as domestic heating in winter and increased biogenic emissions in summer. Also, seasonal differences in meteorological conditions mainly in case of temperature, humidity, and solar radiation were shown to play a role in aerosol characteristics. A comparison of aerosol properties at two different measurement sites, namely a rural and suburban, enabled us to better characterize the role of background aerosol and the influence of the city. Furthermore, a transformation of aerosol particles entering indoors from outdoors was also studied within this thesis. The influence of indoor/outdoor temperature and humidity gradient as well as presence of new particle formation events on the indoor/outdoor ratio was...
Elemental carbon in highly time and size resolved atmosheric aerosol by image analysis
Voldánová, Zdeňka ; Hovorka, Jan (advisor) ; Schwarz, Jaroslav (referee)
In this study a new optical method for highly time and size resolved atmospheric elemental carbon has been described. For this purpose has been used image analysis of 3 DRUM strips with three size fractions deposited (2,5-1,15 µm; 1,15-0,34 µm; 0,34-0,1 µm). Strips were scanned by Fotoscanner HP ScanJet 8200 with optical resolution of 600 dpi. For the analysis of images Matlab program was used, in which the images are transformed to a matrix of grayscale values. The output of this program are time series of grayscale values for each transformed image. Because the time series consist of data in 5 minute intervals, for comparing with hourly PM2,5 EC data obtained from the Sunset EC/OC analyzer, it was necessary to have hourly time series. The precise method of this new approach to determine concentration of atmospheric BC is described in this thesis. In addition, it contains description of the procedures connected with calibrations and controls of sectional outputs. Using linear regression, the daily averages for black carbon are compared with daily EC data. Similarly, hour averages are compared by linear regression also. The analysis performed proved very good relation between daily EC and daily BC described by formula (EC ~ 1.0399 + 0,0117*BC). In respect to hourly averages, a very different...
Dynamics of vertical and horizontal profiles of atmospheric aerosol in planetary boundary layer
Esterlová, Jana ; Hovorka, Jan (advisor) ; Jančík, Petr (referee)
The boundary layer of the atmosphere is a layer of air with thickness about 1 km above the ground. Open-cast mining is one of activities that polutes the air in this layer. It generates particulate matter (PM) mostly in size of aerodynamic diameter 1 - 10 µm - coarse patricles. The companies that does the mining pays for their emissions due to the law. However, these emissions are not experimentraly measured, they are calculated from given equation consisting of factors like the size of mining area, etc. Some papers have shown significantly higher concentrations of Coarse particles (or PM10) in surroundings of the mine. Other papers have found out that the origin of these high concentrations didn't come from the mining activities but is caused due to the activities at the place of measuring or nearby. There aren't many papers that measure the PM concentrations in the air in the mining area. This thesis shows the results of airship measurements in the air layers of the open-cast mine and above them. The experimentral site was brown coal mine Bílina in the North of The Czech Republic in important mining area. The measurements took place in December 2017. For measuring the number and mass concentrations was used APS - Aerodynamic Particle Sizes Spektrometr by TSI which sorts out the data into...

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