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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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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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Processes of Nanoparticle Formation in Low Temperature Plasma
Brožek, V. ; Mastný, L. ; Moravec, Pavel ; Neufuss, Karel ; Ondráček, Jakub ; Ždímal, Vladimír
This work describes the synthesis of nanoparticles during interaction of several different metals (Ag) or their respective oxides (TiO2, Cr2O3) with oxygen-hydrogen plasma having temperatures above 25000 K. Resulting nanoparticles and/or their aggregates in the size range of 25-300 nm were deposited on metallic targets and/or trapped in the water filters and separated using ultra-centrifugal apparatus. The aerosol spectrometer SMPS 3936 (scanning mobility particle sizer) was used to study the particle size distribution of generated nanoparticles in the size range 14 – 700 nm. In order to extend the measured particle size range towards larger sizes, the APS 3321 spectrometer (aerodynamic particle sizer) with the size range 500-20000 nm was used simultaneously. Both spectrometers were set-up to sample with three minute time resolution. Process conditions and production of inorganic nanoparticles of defined composition are discussed in this work.
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Deposition of Aerosol Particles on Filter Surfaces
Smolík, Jiří ; Mašková, Ludmila ; Zíková, Naděžda ; Ondráček, Jakub
The simple model showed that the particle penetration and deposition depend on particle size and width of the gap, with the depth of the penetration limited by parallel diffusional deposition on filter surfaces. Smaller particles penetrate faster and deeper resulting in higher particle number concentration of deposited particles but higher mass is transported by larger particles. The results of modelling have been qualitatively confirmed by Ion Chromatography using sulphate as marker for deposited particles.
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Aerosol Particles in the Indoor Environment of the National Library in Prague
Andělová, Ludmila ; Smolík, Jiří ; Džumbová, Lucie ; Ondráček, Jakub ; Součková, M. ; Stankiewicz, J. ; López-Aparicio, S. ; Grontoft, T.
Particulate matter in the indoor air in exhibition rooms is a serious risk to works of art stored there. In the Baroque Library Hall of the National Library we examined concentrations and compositions of aerosol particles during 4 intensive campaigns in different seasons of year. Time variation of fine particles concentration indicated outdoor origin with traffic as the most probable source. The concentration of coarse particles revealed periodic increase and decrease, corresponding to beginning and end of visiting hours, indicating visitors as a source of these particles. The major water-soluble inorganic components of the fine particle mode were ammonium sulphate and nitrate, with indoor nitrate concentrations decreasing to zero. It was apparently caused by evaporation of ammonium nitrate after penetration indoors. Crustal elements in both indoor and outdoor samples were predominantly associated with coarse particles.
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