National Repository of Grey Literature 78 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Experimental Methods to Study Aerosol Nanoparticles.
Ždímal, Vladimír ; Schwarz, Jaroslav ; Ondráčková, Lucie ; Ondráček, Jakub
During the last few decades, the experimental possibilities of studying aerosol particles have grown enormously. Not only is it possible to determine the particle size distribution in different metrics, not only can the chemical composition of the size-resolved aerosol be determined, but methods have been developed over the last two decades that allow all of these tasks to be handled in real time. These methods stem from several basic physical principles: molecular diffusion based on Brownian motion, electrostatic separation of particles with predictable charge, condensational growth of particles, gravitational settling, acceleration of particles in nozzles, inertial impaction, and light scattering on particles.\nHowever, if we are specifically interested in separating particles smaller than 100 nanometers in diameter, the choice of experimental methods would be substantially reduced. In fact, we have only four physical principles that can be utilized in this size range with reasonable degree of uncertainty: Brownian motion, electrostatics, impaction and condensation. For the determination of the chemical composition in a given size range, the most commonly used is a combination of physical / chemical ionization with mass detection, however, the range of quantifiable substances is greatly limited.\nRecently, exposure monitoring of workers in the production of engineered nanoparticles has become increasingly important. Here, the task is further complicated by the fact that it is necessary to sample directly from the vicinity of the worker's mouth to determine personal exposure. As far as the collection of nanoparticles in the respiratory zone is concerned, there is not yet a great choice of options, and experimental methods are still being developed and tested. A promising alternative is a stationary measurement, where state-of-the-art aerosol spectrometers are located close to the working space of the personnel, so that the actual exposure of the worker can be estimated. In this case, however, it is necessary to calibrate the on-line instruments by comparison with simultaneous personal collection.\n
ACTRIS IMP – participation of the Czech republic in the national research infrastructures and ACTRIS Central facilities.
Ondráček, Jakub ; Váňa, M. ; Klánová, J. ; Holoubek, Ivan ; Ždímal, Vladimír
ACTRIS (The Aerosol, Clouds and Trace Gases Research Infrastructure) is pan-european research infrastructure, having the main goals in provision of high quality scientific data and provision of information about short-lived atmospheric components and processes leading to changes in these components in natural and controlled laboratory environment. ACTRIS is a logical continuation of 15-years development of large research infrastructures being funded by member states and European Commission through the Research Infrastructure Programme (including e.g. EARLINET, EUSAAR, CREATE and CLOUDNET).
Fulltext: Download fulltextPDF
Application of Cross-Section Filtration to Detect and Correct Errors Caused by Technical Problems in SMPS.
Wagner, Zdeněk ; Kovanic, P. ; Zíková, Naděžda ; Ondráček, Jakub ; Schwarz, Jaroslav ; Ždímal, Vladimír
The aim of the work is thus development of a robust algorithm for detection of such errors and their fully automatic correction. The algorithm should be fast so that it could be applied in real time.
Fulltext: Download fulltextPDF
Nanoparticles Personal Exposure Measurement Using a Novel Active Personal Nanoparticle Sampler During Machining and Weldind of Nanomaterials.
Ondráčková, Lucie ; Vlčková, Lucia ; Ondráček, Jakub ; Schwarz, Jaroslav ; Ždímal, Vladimír
Development of nanotechnology has grown very rapidly in past decades. Therefore, it has become increasingly important to monitor the exposure of workers in nanoparticle-based manufacturing operations. In order to determine real personal exposure, it is advisable to take a sample within the worker’s breathing zone. To perform this task, there is not much of a choice yet, since experimental methods are still under development. Recently, a novel active personal nanoparticle sampler (PENS) has been developed, collecting both respirable mass fraction (RPM) and nanoparticles (NPs) simultaneously.
Fulltext: Download fulltextPDF
Indoor Particles of Outdoor Origin in Depositories.
Mašková, Ludmila ; Smolík, Jiří ; Trávníčková, Tereza ; Havlica, Jaromír ; Ondráček, Jakub ; Ondráčková, Lucie
Pollution in indoor environment can cause irreversible degradation of materials stored there. The air quality in depositories housed in historical buildings depends mainly on outdoor pollution infiltrated through the building envelope. There are several strategies to control the indoor air pollution. However, most of them including reconstruction, which is problematic in historical monuments. Thus detailed information about indoor air quality and factors influencing it is needed.
Fulltext: Download fulltextPDF
Verification of Electrical and Gravimetric Measurement of ELPI.
Ondráček, Jakub ; Roztočil, Petr ; Ondráčková, Lucie ; Vlčková, Lucia ; Benešová-Ševčíková, Irena ; Procházková, Věra ; Kugler, Josef ; Otáhal, P.
This contribution compares the gravimetric and electrical measurement of ELPI impactor with traditional and very well-established aerosol spectrometers (SMPS, APS and CPC)\non set of well-defined aerosols (different composition, sizes and morphology).
Fulltext: Download fulltextPDF
Measurement of Cloud Condensation Nuclei Concentrations at National Atmospheric Observatory Košetice.
Moravec, Pavel ; Ondráček, Jakub ; Pokorná, Petra ; Ždímal, Vladimír
In this presentation, we report first experience and results of CCN measurements using Dual Column Cloud Condensation Nuclei Counter at the National Atmospheric Observatory Košetice (NAOK), a rural background site in the Czech Republic.
Fulltext: Download fulltextPDF
Origin of Atmospheric Aerosol Based on Data with Different Time Resolution at the National Atmospheric Observatory Košetice.
Pokorná, Petra ; Zíková, Naděžda ; Lhotka, Radek ; Vodička, Petr ; Makeš, Otakar ; Mbengue, Saliou ; Holubová Šmejkalová, Adéla ; Schwarz, Jaroslav ; Ondráček, Jakub ; Ždímal, Vladimír
To improve the air quality the underlying causalities must be well understood,particularly when it comes to aspects such as PM concentration, sources and their origin. The aim of this work was to determine air pollution origin at NAOK based on atmospheric aerosol (AA) data of different time resolution measured during intensive summer campaing.
Fulltext: Download fulltextPDF
ACTRIS IMP – ÚČAST ČESKÉ REPUBLIKY V NÁRODNÍCH VÝZKUMNÝCH INFRASTRUKTURÁCH A TÉMATICKÝCH CENTRECH ACTRIS
Ondráček, Jakub ; Váňa, M. ; Klánová, J. ; Holoubek, Ivan ; Ždímal, V.
ACTRIS (The Aerosol, Clouds and Trace Gases Research Infrastructure) je panevropskou výzkumnou infrastrukturou, jejímž hlavním cílem je tvorba vysoce kvalitních dat a podávání informací o krátkodobých složkách atmosféry a o procesech vedoucích ke změnám těchto složek v přírodním a kontrolovaném laboratorním prostředí. ACTRIS je dlouhodobou aktivitou (již od roku 2012, viz. Obr. 1) více než 100 partnerských organizací po celé Evropě, jejichž cílem je integrace, harmonizace a distribuce vysoce kvalitních vědeckých výstupů poskytovaných nejlepšími pracovišti atmosférického výzkumu v (prozatím) 22 evropských zemích. ACTRIS je logickým pokračováním 15-tiletého rozvoje velkých výzkumných infrastruktur financovaného členskými státy a evropskou komisí (EC) prostřednictvím programu výzkumných infrastruktur (Research Infrastructure programme) zahrnujících např. Projekty EARLINET, EUSAAR, CREATE a CLOUDNET.
Hydroscopic Behaviours of Ammonium Sulfate/Organic Mixtures Including Dicarboxylic Acid and Oligomer.
Bouzidi, Hichem ; Zuend, A. ; Ondráček, Jakub ; Schwarz, Jaroslav ; Ždímal, Vladimír
Here, the hygroscopic behavior of submicron particles composed of ammonium sulfate (AS), dicarboxylic acids (including oxalic acid (OA), malonic acid (MA)), and oligomer Poly(ethylene glycol) (PEG-300 (-CH2OCH2-)n) is investigated with a Hygroscopicity Tandem Differential Mobility Analyzer (HTDMA), under relative humidity (RH) below 100%. The aerosol systems were varied in their complexity and ranged from single-component to more complex systems (2, 3 and 4 components). The experimental data are compared with predictions from Zdanovskii-Stokes-Robinson (ZSR) mixing rule (Stokes and Robinson, 1966) and the thermodynamic model Aerosol Inorganic-Organic Mixtures Functional groups Activity Coefficients (AIOMFAC) (Zuend et al., 2011).
Fulltext: Download fulltextPDF

National Repository of Grey Literature : 78 records found   1 - 10nextend  jump to record:
See also: similar author names
2 Ondráček, J.
9 Ondráček, Jan
1 Ondráček, Jaroslav
4 Ondráček, Jiří
Interested in being notified about new results for this query?
Subscribe to the RSS feed.