Method of Determination of Ion Temperature by the Variations of Satellite Induced Ion Trap Currents and Estimate of the Upper Limit of Ion Temperature at Altitudes of 10,000 Kilometers and Higher According to Data of AES Electron-2

Ion temperature determination by variations of satellite induced ion trap currents - Electron 2 satellite measurements of ion temperatures in ionospher

The magnetic field of Mars estimated from the data of plasma measurements by Soviet artificial satellites of Mars

The dimensions of the obstacle forming the shock wave of Mars are estimated by use of electron trap data from Mars 2, 3, and 5. The mean altitude of the obstacle at the subsolar point can be convincingly explained if the obstacle is the magnetosphere of Mars. On the assumption that Mars has its own dipole magnetic field, the magnetic moment of Mars is estimated, Mm approximately equal to 2 x 10 to the twenty second power gs x cubic cu

Plasma measurements conducted in the vincinity of Venus on the spacecraft VENERA-4

Plasma flux measurements in vicinity of Venus by charged particle traps on Venera-4 spacecraf

Sorption of volatile organic compounds and their mixtures on montmorillonite at different humidity

The vapor-phase sorption of volatile organic compounds (VOCs), i.e. n-hexane, benzene and methanol, along with sorption of their binary mixtures, i.e. benzene/n-hexane and benzene-methanol, on montmorilllonite with different water content was studied. The absolutely dry mineral did not exhibit selectivity towards the studied VOCs sorbed separately. The hydration inhibited sorption of hydrocarbons and promoted that of methanol because of intercalation of its molecules to the interlayer space of the swelling mineral and dissolution in the water films on the external mineral surface. Unlike separate sorption of benzene and n-hexane, sorption of their binary mixture on the montmorillonite, even equal by volume, was selective. The components shared the same sorption sites with benzene being more active due to its ability to form the donor-acceptor complexes with the mineral surface in addition to Van-der-Waals interactions. Opposite, in the benzene/methanol mixture the undoubted predominance of hydrophilic methanol over benzene was revealed, which increased with increasing humidity and was significantly stronger compared to the differences in sorption of methanol and benzene sorbed separately. In the binary mixtures unequal by volume, preadsorption played an important role in VOCs competition with sorption of aliphatic n-hexane being suppressed stronger than that of aromatic benzene. In the benzene/methanol mixture, methanol was predominantly sorbed at all the studied volume ratios and hydration degrees, occupying its specific sorption sites. Hydration of the montmorillonite caused the reverse impact on the sorption of benzene and methanol. As a result, at the full hydration state methanol sorption in the mixture reached that of the pure methanol. © 2014 Elsevier B.V

Effect of the Soil Dehydration Temperature on the Vapor-Phase Sorption of p-xylene

The effect of two methods for the preparation of soil samples for sorption experiments-hard (dehydration at 105°C) and mild (drying over P2O5 at 20°C in vacuum) drying-on the values of the vaporphase sorption of p-xylene was studied depending on the content of organic matter in the soil. It was shown with dark gray forest and chernozemic soils as examples that the hard drying of soil samples taken from the upper layer of the humus profile with a high content (>4%) of organic carbon decreased their sorption capacity in the range of 0-5% by 7-81%. Therefore, the method is unsuitable for these soils. It was also found that the mild method of soil preparation had obvious analytical advantages. © 2010 Pleiades Publishing, Ltd

Description of organic compound vapor-phase sorption by geosorbents: Adequacy of the isotherm approximation

The approximation of isotherms of vapor-phase sorption of organic compounds (OC) is a long-standing problem. It is especially difficult to solve in case of natural heterogeneous sorbents (soils, sediments, aquifers, etc.) since these sorbents contain sites with different sorption activity. The aim of this work was the statistical evaluation of the adequacy of the approximation of isotherms of vapor-phase sorption of OC by geosorbents in water-unsaturated conditions by employing various fitting equations. Vapor sorption isotherms were measured by the static headspace gas-chromatographic analysis method for 27 various organic sorbates (13 hydrocarbons and 5 chlorinated hydrocarbons, 7 oxygenated and 2 nitrogenated OC) on geosorbents (6 soils typical for Middle Russia regions, separate soil layers of 2 dark-gray forest soils, natural zeolite-containing material and bentonite clay, and two clay-humic complexes). The computer-assisted special sorption database with the corresponding software was created, and on the whole, 103 experimental sorption isotherms (86 isotherms measured and 17 taken from the literature) were used for the approximation. The adequacy of isotherm approximation by different sorption models was compared: Brunauer-Emmett-Teller (BET), modified BET (MBET), Pickett-Dellyes (PD), Guggenheim-Anderson-De Boer (GAB), Aranovich-Donohue (AD), Hinz (HZ) and polynomial (PN) equation. For the comparison of the adequacy of isotherm approximation by different equations, the following three criteria were used: (a) s 5% - the average probability of the location of experimental sorption values within the range of 5% of the theoretical curve; (b) two interconnected parameters: R 2 - the square of correlation coefficient and k - the slope tangent for the linear regression (V E; V T) at various sorbate activities; (c) D̄ - relative sample variance as a characteristics of the optimal ratio between numbers of parameters of the fitting equation and its approximation quality. For the description of the vapor sorption of OC by geosorbents, the new MGAB equation (the modified GAB equation) was suggested. It is characterized by the optimal ratio between the 'complexity' of an equation (MGAB is a four-parametrical equation) and its approximation quality (MGAB shows one of the best isotherm approximations). The following rank of the decrease of the adequacy (upon D̄ criterion) of examined fitting equations in relation to the OC sorption isotherm approximation in the whole isotherm range was formed: MGAB > HZ > PD > GAB > AD > PN. © 2005 Elsevier B.V. All rights reserved

Effects of Zeolite-Containing Material and Ammonium Nitrate on Biodegradation of n-Tridecane in Heavy Clay-Loam Leached Chernozem with High Organic Matter Content

Biostimulation based on usage of soil amendments is growing due to their efficiency in removing different petroleum hydrocarbons (PHC) from contaminated sand or loam-sand soils. However, the research on clay-rich soils with higher organic carbon content, in which PHC biodegradation may proceed differently and which are more difficult to clean up, has been less extensive. In a pot experiment, we studied and compared the effects of two soil amendments, natural zeolite-containing material (ZCM, 50 g kg-1) as a bulking agent and ammonium nitrate (0.3 g N kg-1) as a nitrogen fertilizer, on biodegradation of n-tridecane (1 wt.%) in a weakly acidic heavy clay loam leached chernozem with fairly high organic carbon content (3.71%). After 48 days, the nitrogen-amended contaminated soil showed enhancement of both respiratory activity (basal and substrate-induced respiration rates) and the number of n-tridecane- degraders. As a consequence, the extent of n-tridecane biodegradation (86.5%) was essentially higher in the presence of added nitrogen than that in the non-amended soil (73.7%). In contrast, due to the partial retention of n-tridecane molecules in its pores, ZCM retarded biodegradation to 56.0%, showed no significant effect on the number of n-tridecane-degraders and, moreover, enhanced the decomposition of the soil intrinsic organic matter. The obtained data indicate that more precautions should be considered when using porous sorbents such as ZCM for remedial arrangements in PHC-contaminated soils. © 2011 Copyright Taylor and Francis Group, LLC

Use of geoinformation and neurotechnology to assess and to forecast the humus content variations in the steppe soils

This paper reports the results obtained using the systemic basin approach, geoinformation, and neurotechnology for modeling and forecasting of the humus spatial inhomogeneity and content variations in the steppe and dry steppe zones (Kherson oblast, Ukraine

Effect of organic matter on the sorption activity of heavy loamy soils for volatile organic compounds under low moisture conditions

© 2014, Pleiades Publishing, Ltd. The diverse effect of the organic matter content on the sorption of vapors of aromatic and aliphatic hydrocarbons in soils under low moisture (<10.5%) has been revealed in sorption experiments using profile samples from two virgin heavy loamy dark gray forest soils characterized by relatively stable contents of finely dispersed mineral components. The decrease of the hydrocarbon sorption with increasing the content of organic matter under dry conditions (in the moisture range from 0 to 5–6%) indicates its lower sorption activity than that of the clay components and the blocking of the sorption sites on soil minerals by organic matter. At moisture contents above 5–6%, the effect of the soil composition on the sorption activity changes radically: it increases with increasing the content of organic matter. This is due to the inversion of the ratio between the activities of the soil components because of the hydrophilization of the surface of the mineral soil component. As a result, the sorption of water on the minerals reduces the mineral sorption activity to hydrocarbons to a lower level than the activity of organic matter. The maximum manifestation of the revealed blocking effect has been observed for the low-humus soils and this effect decreased with the accumulation of soil organic matter

Tolerance of cultivated and wild plants of different taxonomy to soil contamination by kerosene

In laboratory experiments on leached chernozem contaminated by kerosene (1-15wt.%), germination of 50 plants from 21 families (cultivated and wild, annual and perennial, mono- and dicotyledonous) as affected by kerosene type and concentration and plant features was determined. Tested plants formed three groups: more tolerant, less tolerant, and intolerant, in which relative germination was more than 70%, 30-70% and less than 30%, respectively. As parameters of soil phytotoxicity, effective kerosene concentrations (EC) causing germination depression of 10%, 25% and 50% were determined. EC values depended on the plant species and varied in a wide range of kerosene concentrations: 0.02-7.3% (EC 10), 0.05-8.1% (EC 25), and 0.2-12.7% (EC 50). The reported data on germination in soils contaminated by oil and petrochemicals were generalized. The comparison showed that at very high contamination levels (10 and 15%) kerosene was 1.3-1.6 times more phytotoxic than diesel fuel and 1.3-1.4 times more toxic than crude oil, and at low (1 and 2%) and medium (3 and 5%) levels the toxicity of these contaminants was close differing by a factor of 1.1-1.2. Tolerance of plants to soil contamination had a species-specific nature and, on the average, decreased in the following range of families: Fabaceae (germination decrease of 10-60% as compared to an uncontaminated control)>Brassicaceae (5-70%)>Asteraceae (25-95%)>Poaceae (10-100%). The monocotyledonous species tested were characterized as medium- and low-stable to contamination, whereas representatives of dicotyledonous plants were met in all groups of tolerance. Tested wild plants, contrary to reference data on oil toxicity, were more sensitive to kerosene than cultivated. No correlation was observed between degree of plant tolerance to kerosene and mass of seeds. The evidence indicates factors as structure and properties of testa, structure of germ, type of storage compounds, and type of seed germination (underground or aboveground) are more important. © 2012 Elsevier B.V