Solar activity and spatial variations of the middle troposphere at the middle and high latitudes of the Northern Hemisphere in winter

Long-term trends are observed in the spatial variability of atmospheric circulation in the 18th–23rd solar cycles in the middle troposphere at the middle and high latitudes of the Northern Hemisphere. The intensification of solar activity in the cycle chronologically coincides with the formation of the extensive anomalies of geopotential at the level of 500 hPa over the northern parts of the Atlantic and Pacific oceans. Upper-level troughs gradually move from middle to high latitudes and, having reached the Arctic Ocean, start moving back to the south. The certain synchronization in the manifestation of natural processes on the Sun and Earth enables considering the features of the spatial distribution of natural anomalies for several solar cycles as a kind of the “marker” of natural long-term fluctuations.     

Dust evolution in the dwarf galaxy Holmberg II

A detailed photometric study of star-forming regions (SFRs) in the galaxy Holmberg II has been carried out using the archival observational data from the far infrared to the ultraviolet obtained with the GALEX, Spitzer, and Herschel telescopes. Spectroscopic observations with the 6-m BTA telescope (Special Astrophysical Observatory of the Russian Academy of Sciences) are used to estimate the ages and metallicities of SFRs. The ages of SFRs have been correlated for the first time with their emission parameters in a wide spectral range and with the physical parameters determined by fitting the observed spectra. It is shown that the fluxes at 8 and 24 µm characterizing the emission from polycyclic aromatic hydrocarbons (PAHs) and hot dust grains decrease with age, but their ratio increases. This implies that the relative contribution from PAHs to the total infrared flux increases with age. It is hypothesized that the detected increase in the ratio of the fluxes at 8 and 24 µm is related to the increase in the relative PAH fraction due to the destruction of larger grains.     

Microwave radiometry of Mars from the Mars 2 and 3 orbiters (preliminary results)

A 3.4-cm wavelength radiometer aboard the Mars 2 and 3 orbiters observed the brightness temperature due to planetary thermal emission in two orthogonal polarizations as a function of position on Mars. Preliminary results for two orbits of Mars 3 show a correlation between subsurface temperature and dielectric constant, interpreted as an effect of porosity.     

Breakup of deep-water methane bubbles

During the Russian Academy of Sciences “MIRI na Baikale. 2008–2009” expedition, deep-water experiments on methane bubbles emerging from the lake bottom at depth of 1400 and 860 meters were carried out. Bubbles escaping the seabed were caught by a trap, which was an inverted glass. Entering in the trap, bubbles became covered by a gas hydrate envelope and then after a time period collapsed into a number of gas hydrate solid fragments. Due to positive buoyancy, fragments remained in the top part of a trap, exhibiting properties of a powder. The glass’s bottom was replaced with a 1 mm mesh grid, allowing the finest gas hydrate particles to sift through the grid, rising upwards. It is proposed that bubble collapse into fragments is related to the pressure drop in the bubble in the course of formation of the gas hydrate envelope. No visible changes in the gas hydrate powder were observed in the course of lifting it to a depth of 380 meters. Shallower than 380 meters, i.e., outside the zone of gas hydrate stability, decomposition of the gas hydrate powder into methane gas was observed.     

西部干旱地区节水钻探的新思路及其配套技术

钻探过程需要消耗大量的地表水.为解决干旱地区工程型缺水的问题,提出了基于孔内地层水局部循环的节水钻探新思路;论述了以脉动器和潜水柱塞泵为主的节水钻探关键技术及其结构设计和参数设计;研讨了开发配套技术的必要性,提出了解决管线刚度和气泡问题、提高吸水效率、对反向行程水击的补偿等6项配套技术.中国属于严重缺水国家,利用地层水实现孔内局部循环钻进是经济、环保的好方法,生产试验表明借助中俄合作开发的节水钻探新思路,达到了既节水5～20倍,又不扰动地层,还能提高钻探效率的目的.     

Density-dependent dispersion in heterogeneous porous media Part II: Comparison with nonlinear models

The results of a series of high-resolution numerical experiments are used to test and compare three nonlinear models for high-concentration-gradient dispersion. Gravity stable miscible displacement is considered. The first model, introduced by Hassanizadeh, is a modification of Fick’s law which involves a second-order term in the dispersive flux equation and an additional dispersion parameter β. The numerical experiments confirm the dependency of β on the flow rate. In addition, a dependency on travelled distance is observed. The model can successfully be applied to nearly homogeneous media (σ² = 0.1), but additional fitting is required for more heterogeneous media.The second and third models are based on homogenization of the local scale equations describing density-dependent transport. Egorov considers media that are heterogeneous on the Darcy scale, whereas Demidov starts at the pore-scale level. Both approaches result in a macroscopic balance equation in which the dispersion coefficient is a function of the dimensionless density gradient. In addition, an expression for the concentration variance is derived. For small σ², Egorov’s model predictions are in satisfactory agreement with the numerical experiments without the introduction of any new parameters. Demidov’s model involves an additional fitting parameter, but can be applied to more heterogeneous media as well.     

Electromagnetic induction in the moon

Electromagnetic induction in a stratified Moon with a trailing cavity is discussed. The influence of the Moon wake is studied by using a two-layer lunar model with a perfectly conductive core. The magnetic field is shown to be independent of the wake length when that quantity is greater than 3 lunar radii. Regions on the sunlit and dark sides where the magnetic field may be described in terms of its first spatial harmonic have been distinguished, together with the corresponding errors admitted. It is in these regions that the electrical conductivity of the Moon can be found with very high accuracy, by simultaneous observations on the lunar surface and in the undisturbed solar wind. Results of these observations can be conveniently related to values of the apparent resistivity. Translated by Miss Eva Vokálová of the Astronomical Institute, Charles University, Prague, Czechoslovakia.     

Gold deposits in dikes of the Yana-Kolyma belt

The ore-bearing dikes widespread in the Yana-Kolyma metallogenic belt vary in composition from granite porphyry to lamprophyres, gabbromonzonite, and dolerite. The dikes make up suites tens of kilometers in extent and up to 8–10 km wide or fields a few thousand square kilometers in area. Previously, the ore mineralization was traditionally referred to the gold-quartz type superimposed on dikes. However, isotopic and thermobarogeochemical data indicate that the mineralization is close to an intrusion-related gold deposit. A deep magma chamber could have been a source of sulfur in sulfides from beresites and quartz veins hosted in the Kolyma dikes. The deposits considered in the paper are permissive for large economic reserves with low and medium Au grades.     

Multistage Alterations of Pre-Vendian Oil-Bearing Rocks of the Baikit Anteclise (Siberian Platform) Based on Rb–Sr and K–Ar Data

Riphean carbonate rocks of the Baikit Anteclise with hydrocarbon raw material reserves exhibit a complicated block structure. Therefore, correlation of sections of even adjacent wells and general understanding of the geological structure of the territory are extremely hampered. The problem becomes more complicated because of multiple epigenetic reworking of Riphean rocks. Study of Rb–Sr and K–Ar systems based on materials from three boreholes drilled on the Baikit Anteclise reveal at least three stages of such reworking dated at about 1400, 1000, and 700 Ma, respectively. Rocks of the whole penetrated pre-Vendian section are assumed to be Early Riphean or even pre-Riphean. Brines saturating them are likely to be related to Vendian–Cambrian saliferous rocks.