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Diffusion Battery – The Renewed Aerosol Spectrometer for Nanoparticles
Holubová Šmejkalová, A. ; Ondráček, Jakub ; Zíková, Naděžda ; Ždímal, Vladimír
The aim of the experiments was to develop new control software for the diffusion battery model DB 3040, in order to optimize measurements with this device. The software allows for larger variability of key control parameters of the diffusion battery and re-opens its application beyond determination of activity size distributions. In comparison with the most widely used method of aerosol spectrometry based on electrical mobility of particles, the method of diffusion battery can be advantageous in situations where we need to measure aerosols of relatively low concentrations with size distributions peaking bellow 20 nanometers.
Fulltext: content.csg -  PDF
Plný tet: SKMBT_C22013010916340 - PDF
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First experiences with inhalation of nanoparticles by small animals
Mikuška, Pavel ; Večeřa, Zbyněk
The contribution describes an inhalation chamber constructed for long-term exposure studies of small animals to nanoparticles under strictly controlled conditions (i.e., temperature, relative humidity, illumination, pressure). Nanoparticles were synthetized on-line in a tube flow reactor using metal organic precursors. Experiments proved that the inhalation chamber is suitable for „whole body“ experiments with small animals
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Penetration of Commercial Filter Materials in Detailed Study
Ondráček, Jakub ; Zíková, Naděžda ; Ždímal, Vladimír
Testing of various filter materials proved the functionality, good precision and reproducibility of a home-made filter tester. The measurements of penetration for standard commercial filter materials might be useful for many scientists and other users working with these materials. The comparison of penetration for different types of filtration materials showed wide variety of penetration curves, MPPS and the maximum penetration. This study also confirmed our initial doubts about the standard filter efficiency testing method, regarding the used testing material, setting of MPPS and measuring only the total penetration of a polydisperse aerosol. Therefore, such a study could serve also as a basis for improvements in the filter efficiency standard method, which seems to give insufficient and in some perspectives limited or even misleading information.
Fulltext: content.csg - PDF
Plný tet: SKMBT_C22012102615351 - PDF
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Size Dependence of Reactive Uptake Coefficient in Chemical Reactions on Aerosol Nanoparticles
Levdansky, Valerij Vladimirovič ; Smolík, Jiří ; Ždímal, Vladimír ; Moravec, Pavel
Chemical reactions in aerosol systems play a significant role in formation of new aerosol particles and their growth in the atmosphere and in various areas of nanotechnology. In the case of nanoscale aerosol particle the size effects can sufficiently affect the rate of chemical reactions both inside the particle and on its surface. The size dependence of a chemical reaction occurring on the nanoparticle surface can be related to the size dependence of the intrinsic activation energy for a chemical reaction and the adsorption kinetics of reactant molecules. Here we consider some aspects of the possible influence of the mentioned effects on the reactive uptake coefficient in the Eley-Rideal mechanism of a chemical reaction.
Fulltext: content.csg - PDF
Plný tet: SKMBT_C22012102615344 - PDF
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Mass Accomodation Coefficient for Nanoscale Aerosol Particles
Levdansky, Valerij Vladimirovič ; Smolík, Jiří ; Ždímal, Vladimír ; Moravec, Pavel
The influence of size effects on physicochemical transformations and transfer processes in the heterogeneous systems with nanoobjects attracts increasing attention of researchers. These problems are of interest for nanotechnology and atmospheric physics. Size effects can influence the cohesive energy as well as the activation energies of vacancy formation and diffusion of atoms in the nanoscale particles (Vanithakumari and Nanda, 2008). Phase transitions (including nucleation) in aerosol systems with nanoscale particles (clusters) also depend on the nanoparticle size (Levdansky et al., 2010). Hear we discuss the size dependence of the mass accommodation coefficient gama in the gas–nanoparticle system.
Fulltext: content.csg - PDF
Plný tet: SKMBT_C22012102615343 - PDF
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Study of Organic Carbon with Different Volatility
Vodička, Petr ; Schwarz, Jaroslav
This work characterizes diurnal trends of OC fractions at Prague suburban site during different seasons over the whole year. Moreover, owing to the parallel measurements at suburban site together with Czech background station Košetice during heating and non-heating season we found which OC fractions are typical for urban and rural environments and their diurnal trends.
Fulltext: content.csg - PDF
Plný tet: SKMBT_C22012102615342 - PDF
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Growth of Sulfuric Acid Nanoparticles at Wet and Dry Conditions
Škrabalová, Lenka ; Brus, D. ; Ždímal, Vladimír ; Lihavainen, H.
Aerosol particles influence global radiative balance and climate directly through scattering and absorbing solar radiation and indirectly by acting as condensation cloud nuclei. The atmospheric nucleation is often followed by a rapid growth of freshly formed particles. The initial growth of aerosol is the crucial process determining the fraction of nucleated particles growing into cloud condensation nuclei sizes (~ 50 nm and larger). Many recent studies have suggested that the sulfuric acid plays a key role in the atmospheric nucleation and subsequent growth of newly formed particles. (Sipilä et al., 2010). The subject of this experimental study is growth behaviour of sulfuric acid nanoparticles produced by homogenous nucleation at wet and dry conditions.
Fulltext: content.csg - PDF
Plný tet: SKMBT_C22012102615341 - PDF
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