Analysis of the hydrogeological conditions in Bulgaria in connection with the radon potential

Natural radon (222Rn) is a radioactive noble gas that occurs in every rock or soil due to the content of radium (226Ra), part of the 238U family, in the lithosphere. Different types of rocks and soils possess different 226Ra content and different permeability. Radon has high mobility and is driven by diffusion and convection with the soil gas throughout connected and water-unsaturated pores and/or cracks in permeable rocks and soils. Therefore, the radon potential of the area could depend on hydrogeology and its particular settings. The study deals with the general characteristics of the groundwater depths in Bulgaria based on the published since 1960’s sources. After analysis of the collected data several distinct regions have been elaborated based on different depth of the groundwater table regarding lithological, tectonic and geomorphological conditions. In addition, zones for screening assessment of groundwater table influence of radon potential have been precised.

Molecular and Thermal Diffusion Coefficients Of n-Dodecane, Isobutylbenzene and Tetrahydronaphtalene Hydrocarbon Mixtures in Porous Media

The thermal diffusion phenomenon was studied in detail by utilizing mixtures consisting of normal alkenes and two aromatics (n-Dodecane, Isobutylbenzene and 1,2,3,4-Tetrahydronaphtalene) based on comparison with available experimental data. This study presents the first report of a comparison of thermal diffusion coefficients of a ternary hydrocarbon mixture with experimental data in the literature. In addition to thermal diffusion coefficients, molecular diffusion coefficients are also measured and compared with Benchmark experimental values for three binary mixtures. Furthermore, molecular and thermal diffusion coefficients for three binary mixtures are used to correlate and estimate the thermal diffusion coefficients in the ternary hydrocarbon mixture. The thermo-solutal convection in porous media was simulated numerically using the Firoozabadi model in order to investigate the composition variation due to the processes of thermal diffusion and convection. Finally, a multi-porosity/multi-permeability model was utilized to further analyze the processes of thermal diffusion and convection in fractured porous media.

Molecular and Thermal Diffusion Coefficients Of n-Dodecane, Isobutylbenzene and Tetrahydronaphtalene Hydrocarbon Mixtures in Porous Media

The thermal diffusion phenomenon was studied in detail by utilizing mixtures consisting of normal alkenes and two aromatics (n-Dodecane, Isobutylbenzene and 1,2,3,4-Tetrahydronaphtalene) based on comparison with available experimental data. This study presents the first report of a comparison of thermal diffusion coefficients of a ternary hydrocarbon mixture with experimental data in the literature. In addition to thermal diffusion coefficients, molecular diffusion coefficients are also measured and compared with Benchmark experimental values for three binary mixtures. Furthermore, molecular and thermal diffusion coefficients for three binary mixtures are used to correlate and estimate the thermal diffusion coefficients in the ternary hydrocarbon mixture. The thermo-solutal convection in porous media was simulated numerically using the Firoozabadi model in order to investigate the composition variation due to the processes of thermal diffusion and convection. Finally, a multi-porosity/multi-permeability model was utilized to further analyze the processes of thermal diffusion and convection in fractured porous media.