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In our study we estimate relationships between quantitative parameters of relief, soil runoff regime, and spatial distribution of radioactive pollutants in the soil. The study is conducted on the test arable area located in basin of the upper Oka River (Orel region, Russia). Previously we collected rich amount of soil samples, which make it possible to investigate redistribution of the Chernobyl-origin cesium-137 in soil material and as a consequence the soil runoff magnitude at sampling points. Currently we are describing and discussing the technique applied to large-scale mapping of the soil runoff. The technique is based upon the cesium-137 radioactivity measurement in the different relief structures. Key stages are the allocation of the places for soil sampling points (we used very high resolution space imagery as a supporting data); soil samples collection and analysis; cali bration of the mathematical model (using the estimated background value of the cesium-137 radioactivity); and automated compilation of the map (predictive map) of the studied territory (digital elevation model is used for this purpose, and cesium-137 radioactivity can be predicted using quantitative parameters of the relief). The maps can be used as a support data for precision agriculture and for recultivation or melioration purposes. [ABSTRACT FROM AUTHOR]

Ageing of the mix of thermobitumen and oil (TBO) formed at low-temperature pyrolysis of kukersite in autoclaves was studied, and the effect of pyrolysis conditions on the share of fractions soluble in hexane, benzene and tetrahydrofurane was described. The results reveal a decrease in the total weight of TBO and solid residue at storage. During a month of ageing in open air the additional weight loss of the initial organic matter reaches 10- 15%. At that, the yield of TBO decreases and that of the solid residue increases. The fractions of TBO soluble in hexane (maltenes + oil) and in benzene (asphaltenes) decrease, and the fraction soluble in tetrahydrofurane (pre-asphaltenes) increases. The initial yields of hexane and benzene solubles depend on the degree of TBO secondary cracking determined by the pyrolysis conditions. The share of the fraction soluble in hexane increases with pyrolysis temperature and duration and attains 40-50% from the initial organic matter on account of decomposition of asphaltenes concurred with decrease in the total yield of TBO to 60-70% because of gas and coke formation. [ABSTRACT FROM AUTHOR]

Dissolution kinetics of the mix of thermobitumen and oil (TBO) formed at lowtemperature pyrolysis of oil shale in autoclaves was studied for the first time. The pyrolysis temperature was varied in the range of 350-370 °C and duration between 3 and 9 hours. The dissolution of TBO obtained was conducted in a thermostated stirred class reactor and evaluated by the increase in optical density of the solutions with time varying temperature (25-60 °C) and solvent type (benzene, toluene, oil shale petrol and ethanol). A mathematical model was deduced for quantitative description of dissolution kinetics by approximation of the process to the first-order parallel dissolution of two fractions. The dissolution rate coefficients for the fractions were estimated, and contribution of their partial optical densities on the current optical density was described under the conditions studied. [ABSTRACT FROM AUTHOR]