Number of found documents: 946
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Sezónní změny stabilního izotopového složení uhlíku (Δ13C) v aerosolu a plynné fázi na předměstské stanici v Praze
Vodička, Petr; Kawamura, K.; Schwarz, Jaroslav; Ždímal, Vladimír
2022 - Czech
Izotopová frakcionace mezi plynnou a aerosolovou fází je důležitým jevem při studiu atmosférických procesů. V této práci jsme zkoumali sezónní změny poměru stabilních izotopů uhlíku (δ13C) celkového uhlíku (TC, δ13CTC) a organického uhlíku rozpustného ve vodě (WSOC, δ13CWSOC) v jemných aerosolových částicích (PM2,5) a celkového uhlíku plynné fáze (TCgas, δ13CTCgas) na příměstské lokalitě v Praze. In this work, seasonal variations in the stable carbon isotope ratio (δ13C) of total carbon (TC, δ13CTC) and water-soluble organic carbon (WSOC, δ13CWSOC) in fine aerosol\nparticles (PM2.5) as well as in the total carbon of the gas phase (TCgas, δ13CTCgas) were studied. Despite the different seasonal compositions of carbonaceous aerosols, the\nisotope differences (Δδ13C) between the analyzed bulk aerosol parts and gas phases were similar during the seasons. This shows that the fractionation of stable carbon isotopes is a predominantly physical process in which the chemical composition of individual compounds in bulk aerosols does not play a major role. Keywords: atmospheric aerosol; gas phase; δ13C, seasonal variation Available in a digital repository NRGL
Sezónní změny stabilního izotopového složení uhlíku (Δ13C) v aerosolu a plynné fázi na předměstské stanici v Praze

Izotopová frakcionace mezi plynnou a aerosolovou fází je důležitým jevem při studiu atmosférických procesů. V této práci jsme zkoumali sezónní změny poměru stabilních izotopů uhlíku (δ13C) celkového ...

Vodička, Petr; Kawamura, K.; Schwarz, Jaroslav; Ždímal, Vladimír
Ústav chemických procesů, 2022

The Impact of the IMO-2020 Shipping Regulation on the Atmospheric Deposition of Sulfur around the Western English Channel and the Use of the V/Ni ratio as a Shipping Marker.
Windell, L.; Bell, T.; White, C.; Schwarz, Jaroslav; Ussher, S.
2022 - English
Anthropogenic aerosols are shown to have a great impact on marine ecosystems and human health, with the shipping industry contributing as a significant source of these\nemissions, and annual growth on the rise. In the marine environment, shipping emissions often dominate atmospheric deposition of sulfur. With around 70% of shipping activity\nbeing carried out within 400 km of the coast, its contribution to atmospheric sulfur is of great interest. The International Maritime Organisation (IMO) introduced a regulation on\n01/01/2020 restricting global marine fuel sulfur content from 3.5% to 0.5% w/w. The vanadium/nickel (V/Ni) ratio has been widely used as a marker of shipping emissions, with the range of 2.5 to 4 indicating shipping activity. The regulation has called into question the viability of the earlier use of the V/Ni ratio. Keywords: IMO-2020 Global sulfur cap; shipping emissions; sulfur Available in a digital repository NRGL
The Impact of the IMO-2020 Shipping Regulation on the Atmospheric Deposition of Sulfur around the Western English Channel and the Use of the V/Ni ratio as a Shipping Marker.

Anthropogenic aerosols are shown to have a great impact on marine ecosystems and human health, with the shipping industry contributing as a significant source of these\nemissions, and annual growth on ...

Windell, L.; Bell, T.; White, C.; Schwarz, Jaroslav; Ussher, S.
Ústav chemických procesů, 2022

NMR Aerosolomics Study of Water-Soluble Organic Compounds in Size-Resolved Particulate Matter
Horník, Štěpán; Vodička, Petr; Pokorná, Petra; Schwarz, Jaroslav; Ždímal, Vladimír; Sýkora, Jan
2022 - English
Organic aerosols (OA) account for a significant fraction (10 – 90%) of atmospheric particulate matter (Hallquist et al., 2009). The composition of organic aerosols is very complex and is usually characterized by their water solubility. Water-soluble organic compounds (WSOC) constitute a large fraction of OA (10 – 80%) and consist of chemical species containing oxygenated functional groups such as hydroxyl, carboxyl, or carbonyl groups. NMR spectroscopy represents an alternative to commonly used techniques (gas chromatography-mass spectrometry, liquid chromatography-based techniques) for WSOC analysis. Our recently introduced method, called NMR aerosolomics, allows quantitative analysis of dozens of individual compounds from different aerosol samples. An important part of the characterization of aerosols is their classification by particle size. The analysis of individual compounds in the size-resolved fractions of the WSOC class has been performed only in a few studies that focus mainly on a particular subclass of compounds or use multiple analytical techniques. Keywords: NMR; aerosolomics; organic composition Available in a digital repository NRGL
NMR Aerosolomics Study of Water-Soluble Organic Compounds in Size-Resolved Particulate Matter

Organic aerosols (OA) account for a significant fraction (10 – 90%) of atmospheric particulate matter (Hallquist et al., 2009). The composition of organic aerosols is very complex and is usually ...

Horník, Štěpán; Vodička, Petr; Pokorná, Petra; Schwarz, Jaroslav; Ždímal, Vladimír; Sýkora, Jan
Ústav chemických procesů, 2022

Závislost aktivace aerosolu na meteorologických podmínkách
Zíková, Naděžda; Pokorná, Petra; Sedlák, Pavel; Ždímal, Vladimír
2022 - Czech
V šesté hodnotící zprávě IPCC byla nejvyšší hodnota aerosolového forcingu připsána tzv. nepřímému aerosolovému efektu, tedy interakci mezi atmosférickým aerosolem (AA) a oblačností (Arias a kol., 2021). Tato interakce závisí na množství aktivovaných oblačných jader, což je veličina, kterou je náročné měřit i modelovat. Proto byl zkoumán vliv velikostně diferencované aktivace AA na meteorologických veličinách a jevech. Four intensive in-situ campaigns focused on aerosol-cloud interactions were performed in the autumn and spring months from Nov 2018 to Apr 2020 at Milešovka Mountain in Czechia to bring more insight into size-dependent aerosol activation and dependence on its origin for a wide variety of meteorological parameters. Most activated particles were larger than 100 nm, with a mode over 200 nm. For the description of the changes in the activation, no effect of photochemistry was found, in contrast, some dependence on relative humidity, temperature, wind speed, and liquid water content (LWC) proved to be useful. The strongest connection was found between activation and LWC. For LWC below 0.1 g/m3, in the LWC-limited regime, the LWC values and variables effecting the LWC were the main factors influencing the activation, while different parameters could have played a role at LWCs over 0.1 g/m3, in the LWC-independent regime. Keywords: atmospheric aerosols; activation; meteorological phenomena Available in a digital repository NRGL
Závislost aktivace aerosolu na meteorologických podmínkách

V šesté hodnotící zprávě IPCC byla nejvyšší hodnota aerosolového forcingu připsána tzv. nepřímému aerosolovému efektu, tedy interakci mezi atmosférickým aerosolem (AA) a oblačností (Arias a kol., ...

Zíková, Naděžda; Pokorná, Petra; Sedlák, Pavel; Ždímal, Vladimír
Ústav chemických procesů, 2022

Three Years of Experience with Measurement of Cloud Condensation Nuclei Concentrations Using Cloud Condensation Nuclei Counter CCN-200
Moravec, Pavel; Lhotka, Radek; Ždímal, Vladimír
2022 - English
Aerosol particles in the atmosphere that allow water vapor to condense and form cloud droplets are called Cloud Condensation Nuclei (CCN). Elevated concentrations of \nCCN tend to increase the concentration and decrease the size of droplets. This can lead to suppression of precipitation in shallow and short-lived clouds and to greater convective \noverturning and more precipitation in deep convective clouds. The response of cloud properties and precipitation processes to increasing anthropogenic aerosol concentrations represents one of the largest uncertainties in the current understanding of climate change. One of the fundamental challenges is to determine the ability of aerosol particles to act as CCN under relevant atmospheric conditions. Knowledge of the spatial and temporal distribution in the atmosphere is essential to incorporate the effects of CCN into meteorological models of all scales, Huang et al. (2007). Long-term CCN measurements are performed at aerosol monitoring sites such as those forming ACTRIS (Aerosols, Clouds and Trace Gases Research Infrastructure) network. In this paper, we present the three-year experience of measuring CCN concentrations over the National Atmospheric Observatory Košetice (NAOK), a rural background site in the Czech Republic. The first results of these measurements were presented by Mishra et al. (2022) Keywords: atmospheric aerosols; CCN; CCN concentration measurement Available in a digital repository NRGL
Three Years of Experience with Measurement of Cloud Condensation Nuclei Concentrations Using Cloud Condensation Nuclei Counter CCN-200

Aerosol particles in the atmosphere that allow water vapor to condense and form cloud droplets are called Cloud Condensation Nuclei (CCN). Elevated concentrations of \nCCN tend to increase the ...

Moravec, Pavel; Lhotka, Radek; Ždímal, Vladimír
Ústav chemických procesů, 2022

Personal exposure measurement during dental nanocomposite grinding
Ždímal, Vladimír; Ondráčková, Lucie; Ondráček, Jakub; Schwarz, Jaroslav; Bradna, P.; Roubíčková, A.; Pelclová, D.; Rössnerová, Andrea
2022 - English
The purpose of this study was to measure the personal exposure of each participant of the study and to compare the results with those of static monitoring. Personal nanoparticle sam-plers (PENS), which can simultaneously detect both nanoparticles (PM0.1) and respirable parti-cles (PMA), were used to determine personal exposure (Tsai et al., 2012). Area monitoring in-cluded measurement of mass concentrations using the Berner Low Pressure Impactor (BLPI 25/0.018 /2, Hauke GmbH, Gmunden, Austria) and the Low Volume Sampler (LV5, Sven Leckel Ingenieurbüro GmbH, Germany). The number concentrations and their size distributions were measured with the Scanning Mobility Particle Sizer (5MP5 3936, T5I Inc., USA) and the Aerody-namic Particle Sizer (APS 3321, TSI Inc., USA). Measurements with all of the above- mentioned instruments were performed in four shifts with six participants per shift. Each participant milled for 10 minutes and then remained in the room until the group finished the session, so the total exposure lasted about 70 minutes. Due to the high content of filler nanoparticles, the nanocom-posite Filtek Ultimate (body A2, 3M ESPE, USA) was selected for these measurements. Keywords: dental treatment; personal exposure; nanocomposites Available in a digital repository NRGL
Personal exposure measurement during dental nanocomposite grinding

The purpose of this study was to measure the personal exposure of each participant of the study and to compare the results with those of static monitoring. Personal nanoparticle sam-plers (PENS), ...

Ždímal, Vladimír; Ondráčková, Lucie; Ondráček, Jakub; Schwarz, Jaroslav; Bradna, P.; Roubíčková, A.; Pelclová, D.; Rössnerová, Andrea
Ústav chemických procesů, 2022

Multiplication of urea sites—impact on binding phosphates
Salvadori, Karolína
2022 - English
In our work, we focused on the synthesis of sensory groups based on urea structural motifs, suitable for binding phosphates. These units were tested for their selectivity and binding efficiency in HB competitive solvent (DMSO).\n Keywords: urea; phosphates; concentrations Available in a digital repository NRGL
Multiplication of urea sites—impact on binding phosphates

In our work, we focused on the synthesis of sensory groups based on urea structural motifs, suitable for binding phosphates. These units were tested for their selectivity and binding efficiency in HB ...

Salvadori, Karolína
Ústav chemických procesů, 2022

A seven-years based characterization of aerosol light scattering properties at Central European rural site: Variability and source apportionment
Suchánková, Lenka
2022 - English
In addition, the sources of scattering aerosols, chemical composition, meteorological conditions, particle size distribution, and radiative forcing will be further investigated at NAOK to better understand the direct effects of aerosols on local climate. Keywords: organic aerosol; measurements; aerosol light scattering properties Available in a digital repository NRGL
A seven-years based characterization of aerosol light scattering properties at Central European rural site: Variability and source apportionment

In addition, the sources of scattering aerosols, chemical composition, meteorological conditions, particle size distribution, and radiative forcing will be further investigated at NAOK to better ...

Suchánková, Lenka
Ústav chemických procesů, 2022

Use of photoautotrophic microorganisms in bioremediation of surface waters
Mušálková, Petra
2022 - English
The aim of my thesis is to develop an alternative method of removing this overplus of nutrients from surface waterbodies in a biological way, withthe use of microalgae and cyanobacteria. \n Keywords: microalgae; cyanobacteria; water eutrophication Available in a digital repository NRGL
Use of photoautotrophic microorganisms in bioremediation of surface waters

The aim of my thesis is to develop an alternative method of removing this overplus of nutrients from surface waterbodies in a biological way, withthe use of microalgae and cyanobacteria. \n

Mušálková, Petra
Ústav chemických procesů, 2022

Experimental study of bubble dynamics in aqueous solutions of simple alcohols: CFD validation data
Crha, Jakub
2022 - English
The aim of this work was to obtain experimental values of terminal velocities and shape deformations for a wide range of bubble sizes and compare them with theoretically calculated values. These data were obtained for the whole concentration range of aqueous solutions of 1-propanol and ethanol and will be used for validation of CFD results in\nfuture work.\n Keywords: bubble dynamics; water-alcohol mictures; viscosity Available in a digital repository NRGL
Experimental study of bubble dynamics in aqueous solutions of simple alcohols: CFD validation data

The aim of this work was to obtain experimental values of terminal velocities and shape deformations for a wide range of bubble sizes and compare them with theoretically calculated values. These data ...

Crha, Jakub
Ústav chemických procesů, 2022

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