Modelling accidental releases of dangerous gases into the lower troposphere from mobile sources

The article reports the results of different methods of modelling releases and dispersion of dangerous gases or vapours in cases of major accidents from road and rail transportation in urban zones. Transport accidents of dangerous substances are increasingly frequent and can cause serious injuries in densely inhabited areas or pollution of the environment. For quantitative risk assessment and mitigation planning, consequence modelling is necessary. The modelling of dangerous substance dispersion by standard methods does not fully represent the behaviour of toxic or flammable clouds in obstructed areas such as street canyons. Therefore the predictions from common software packages as ALOHA, EFFECTS, TerEx should be augmented with computational fluid dynamics (CFD) models or physical modelling in aerodynamic tunnels, and further studies are planned to do this. The goal of this article is to present the results of the first approach of modelling using these standard methods and to demonstrate the importance of the next development stage in the area of transport accident modelling of releases and dispersions of dangerous substances in urban zones in cases of major accident or terrorist attacks

ANALYSIS OF THE ν2\nu_2 BAND OF THE FCO2_2 RADICAL: PRELIMINARY RESULTS

Kolesnikova, Varga, Beckers, Simeckova, Zelinger, Nova Striteska, Kania, Willner, and Urban, J. Chem Phys 128, 224 (2008)Author Institution: Laboratoire Inter Universitaire des Systemes Atmospheriques; CNRS, Universites Paris 12 et 7, 61 Av du General de Gaulle, 94010 Creteil; Cedex France; VSB-Technical University of Ostrava, Faculty of; Safety Engineering, Lum\irova 13, CZ-70030, Ostrava 3 - Vyskovice, Czech Republic; Institute of Thermomechanics, v.v.i., Academy of Sciences of the Czech Republic, Dolejskova 5; CZ-18200 Prague 8, Czech Republic; Inorg. Chemistry, University of Wuppertal, D-42119 Wuppertal, GERMANY; J. Heyrovsky Institute of Physical; Chemistry, Academy of Sciences of the Czech Republic, Dolejskova 3, CZ-18223 Prague 8; Czech Republic; VSB-Technical University of Ostrava, Faculty; of Safety Engineering, Lum\irova 13, CZ-70030, Ostrava 3 - Vyskovice, Czech Republic; Institute of Thermomechanics, v.v.i, Academy of Sciences of the Czech Republic, Dolejskova 5; CZ-18200 Prague 8, Czech Republic.The unique fluoroformyloxyl radical (FCO$_2$) is assumed to participate in atmospheric processes such as the degradation of hydrofluorocarbons that have been considered as chlorofluorocarbon substitutes. Despite this atmospheric interest, the molecular and spectroscopic properties of FCO$_2$ have not yet sufficiently been explored. The high resolution FT IR gas phase spectrum of the fluoroformyloxyl (FCO$_2$) radical was recorded in the 650 - 1500~cm$^{-1}$ spectral range at the University of Wuppertal. Using this spectrum and the ground state parameters achieved recently we carried out the first high resolution study of the $\nu_2$ $A$-type band (C-F stretching mode) centered at 970.209 cm$^{-1}$. The analysis was difficult because the band is congested. In addition the spin doublets are difficult to identify except for high K$_a$ values. However, we could take advantage of the fact that only K$_a$=odd values are observable for symmetry reasons. The line position calculation accounts for the spin rotation doubling and for the Fermi-type resonances linking the 2$^1$ and 5$^2$ spin rotation energy levels