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Existenční teorie pro velká data pro nestacionární proudění vazkopružných tekutin
Pušman, Jan ; Málek, Josef (advisor) ; Pokorný, Milan (referee)
In the present. work, we investiga te some evolutionary viscoelastic fluid models of Oldroyd type. The model consis of the incompressible Navier-Stokes equations coupled with transport equations for components of stress tensor. We provide a more detailed proof of the exis tence of weak solutions in case of space periodic boundary conditions following the original paper by Lion s and Masrnoudi. The proof is based on exploiting the propagation in time of the compactness of the solutions, i.e. the property that if we take a sequence of weak solution s which converges weakly and such that the corresponding initial conditions converge strongly, then the weak limit is also a solution.
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Markers of Oxidative Stress are Elevated in Workers Exposed to Nanoparticles
Pelclová, D. ; Ždímal, Vladimír ; Fenclová, Z. ; Vlčková, Š. ; Schwarz, Jaroslav ; Pušman, Jan ; Zíková, Naděžda ; Syslová, K. ; Kuzma, Marek ; Navrátil, Tomáš ; Zakharov, S. ; Kačer, P.
Health-effects of nanoparticles in humans are little understood. Pre-shift and post-shift spirometry, markers in exhaled breath condensate (EBC), and fractional exhaled nitric oxide (FeNO) were measured both in 20 workers exposed to TiO2 aerosol and 19 controls. Particle number size distributions were monitored by aerosol spectrometers SMPS and APS, covering the overall size range 15 nm-10 μm. Simultaneously, the spatial distributions of total particle number and mass concentrations were determined using a particle number concentration monitor (P-TRAK) and a monitor of particle mass concentrations (DustTRAK DRX). Total aerosol concentrations in the production plant varied greatly in both space and time; number concentrations 1x104-2x105 particles/cm3 and mass concentrations 0.1-30 mg/m3. In the workshops, 90% of the particles were smaller than 100 nm in diameter and particle concentrations were 10x higher than in the control room.
Fulltext: content.csg -  PDF
Plný tet: SKMBT_C22013111914100 - PDF
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Aerosol Dynamics – Mathematical Formulation, Numerical Solution
Pušman, Jan ; Ždímal, Vladimír
Mathematical and computer modeling of aerosols is used in a wide range of applications including atmospheric physics and chemistry, environmental protection, nuclear safety and industrial applications such as the production of nanomaterials. The aim of this work is twofold. We present a closer look at some aspects of mathematical modeling of aerosols as sub-discipline of continuum mechanics. We provide an overview of common methods and we discuss limitations on their applicability. The long-term goal of authors is to create a new solver of aerosol dynamics based on OpenFOAM platform. A mathematical formulation of the problem is given in terms of Navier-Stokes- Fourier system coupled with evolutionary equation governing aerosol size distribution. Trial numerical simulations in a 2D channel were performed under physically simplified conditions.
Fulltext: content.csg - PDF
Plný tet: SKMBT_C22012102615340 - PDF
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