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Nonequilibrium condensation processes in steam turbines in the light of new measurements of heterogeneous particles
Hrubý, Jan ; Kolovratník, M. ; Ždímal, Vladimír ; Bartoš, Ondřej ; Moravec, Pavel ; Jiříček, I.
In a steam turbine, droplets are formed either homogeneously or via heterogeneous nucleation on pre-existing heterogeneous particles. In a pioneering work, the present team developed a system to measure the number and size of heterogeneous particles down to diameter of 3 nm. This work reports on measurements at Power Plant Prunéřov II. For the first time, the data is at higher parameters (0.27 MPa, 250°C), and the diffusion battery was used to determine the size distribuition of the particles, showing count-mean diameter of about 13 nm.
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Porovnání ultrajemných atmosférických aerosolů v Praze a Budapešti
Matějková, Daniela ; Borsós, T. ; Ždímal, Vladimír ; Salma, I. ; Schwarz, Jaroslav ; Smolík, Jiří
Data measured in Prague suburbs and Budapest city center have been compared in the time period from November 1, 2008 until August 31, 2009 in the size range from 10 nm to 1 µm. Total average particle number concentrations were calculated, 6.8×103 particles/cm3 in Prague, and 1.3×104 particles/cm3 in Budapest. The size distributions were mostly bimodal with the mode located either in the Aitken (25–100 nm) or in the accumulation mode range (> 100 nm). When new particle formation started in the atmosphere, the nucleation mode (< 25 nm) appeared growing from the lowest detectable sizes upwards.
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Deposition of Inhalants in the Human Respiratory Tract
Kovářová, E. ; Ždímal, Vladimír
Size distributions were determined of particles generated by two types of aerosol inhalers, using three different dosage forms, each of them containing another active substance. It was found that only 6% of inhaled particles deposit in the target region even though 90% of them reach this region. When holding the breath after dose aplication, the deposition efficiency may increase a little. Despite some differences between the individual dosage forms none of them proved to be too beneficial in terms of particle deposition efficiency in the target region. Measurements under various temperatures and relative humidities showed that all studied inhalants are hydrophobic; the measured size distributions essentially did not change even at high relative humidities simulating conditions in the real respiratory tract.
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