Seasonal, interannual and long-term variability of precipitation and snow depth in the region of the Barents and Kara seas     

Yevgeniy I. Aleksandrov  Nikolay N. Bryazgin  Eirik J. Førland  Vladimir F. Radionov  Pavel N. Svyashchennikov 《Polar research》2005,24(1-2):69-85

Observation data of temperature, precipitation and snow depth have been compiled and generalized climatologically for a network of 38 stations in and around the Barents and Kara seas, for the period 1951–1992. The monthly precipitation totals were corrected for measuring errors, and the correction method is described in detail. The corrected precipitation values show that the annual precipitation in the region ranges from more than 500 mm along the coast of the Kola Peninsula to less than 200 mm in parts of the north-eastern Kara Sea. The solid fraction of the annual precipitation ranges from 70% in northern parts to 35% in southern parts. For the period 1951–1992 the analysis indicates decreasing trends in annual values of temperature, precipitation and snow depths in the north-eastern parts of the region.  相似文献   

The cycling of Ni,Zn, Cu in the system “mine tailings–ground water–plants”: A case study     

Nikolay V. Sidenko  Elena I. KhozhinaBarbara L. Sherriff 《Applied Geochemistry》2007

The comparative behaviour of Ni, Cu and Zn in the system “mine tailings–ground water–plants” has been investigated at the Ni–Cu mine site operated by INCO Ltd. Thompson Operations, Thompson, Manitoba. Oxidation of sulphide minerals causes the release of metals from exposed tailings containing Ni ∼2000 ppm, Cu ∼150 ppm and Zn ∼100 ppm to the ground water, which contains 350 mg/L Ni, 0.007 mg/L Cu, and 1.6 mg/L Zn. The metal concentration in the ground water is affected by the relative proportions of sulfide minerals, the rate of oxidation of sulphide minerals (Ni-bearing pyrrhotite > sphalerite > chalcopyrite), and the affinity of the metals for secondary Fe-phases (Ni > Zn > Cu).  相似文献   

Lidar and Sun photometer observations of atmospheric boundary-layer characteristics over an urban area in a mountain valley     

Nikolay Kolev  Ivan Grigorov  Ivan Kolev  P. C. S. Devara  P. Ernest. Raj  K. K. Dani 《Boundary-Layer Meteorology》2007,124(1):99-115

We present measurements of the vertical aerosol structure and the aerosol optical depth in the lower troposphere performed above the city of Sofia (an urban area situated in a mountain valley), western Bulgaria by means of a ground-based aerosol lidar operating continuously for a number of years. The lidar measurements were accompanied by measurements of the aerosol optical depth (AOD) in the visible and near infrared regions of the spectrum performed in October 2004 using Microtops II radiometers. The maximum values of the AOD were found to occur 1–2 h before the complete development of the atmospheric boundary layer, i.e. during the residual layer destruction, which confirms our hypothesis concerning the slope circulation effect on the processes taking place in the atmospheric boundary layer. The AOD values obtained by the lidar are lower than those taken by the sun photometer. Further, the AOD exhibits two different types of behaviour. In the case of a ‘clear atmosphere’ (i.e. in the absence of volcanic eruptions and/or dust transport from the Sahara) most of the aerosol accumulated within the atmospheric boundary layer over the urban area considered. The combined use of the two instruments allows the comparison between the optical characteristics of the atmospheric aerosol (e.g. aerosol extinction coefficient, etc.) obtained by the lidar and through an independent method (sun photometer).  相似文献   

Element partitioning between immiscible borosilicate liquids: A high-temperature centrifuge study     

Ilya V VekslerAlexander M Dorfman  Donald B Dingwell  Nikolay Zotov 《Geochimica et cosmochimica acta》2002,66(14):2603-2614

The main objectives of this study were to investigate conditions for stable and metastable liquid immiscibility in dry borosilicate synthetic systems and to evaluate effects of temperature and bulk melt composition on two-liquid element partitioning and boron speciation. To distinguish between the stable immiscibility and quench heterogeneity, we used high-temperature centrifuge phase separation. For the case of stable liquid immiscibility, silica-rich (LS) and borate-rich (LB) conjugate liquids formed two distinct layers separated by a sharp meniscus. The liquids were quenched into glasses, which were analysed by electron microprobe. Some of the glasses were also studied by Raman spectroscopy. We used several synthetic mixtures along the danburite-anorthite (CaB₂Si₂O₈-CaAl₂Si₂O₈) and danburite-reedmergnerite (CaB₂Si₂O₈-NaBSi₃O₈) joins. In addition, we studied four complex, six-component, Mg-bearing compositions with variable Na₂O and Al₂O₃ contents. The experiments show that the width of the LS-LB miscibility gap decreases more rapidly with the B-Al substitution (in the danburite-anorthite join) than with the Ca-Na substitution, implying that interactions between network-forming elements have a greater effect on borate-silicate unmixing than the nature of network-modifying cations. Ca and Mg partition strongly to the depolymerised borate-rich liquid with LB-LS partition coefficients of ∼40 and higher. On the other hand, two-liquid partition coefficients of Na and Al in most cases are close to 1 and show complex variations with temperature and bulk melt composition. Raman spectra of LB glasses quenched at different temperatures suggest that the proportion of trigonal boron in bulk boron content decreases with decreasing temperature. The change in boron speciation appears to affect Al and Na two-liquid partitioning in such a way that at low temperatures, the latter element becomes more compatible with LS.  相似文献   

Morphogenesis and composition of native gold in the Chelopech volcanic-hosted Au–Cu epithermal deposit, Srednogorie zone, Bulgaria   总被引：1，自引：0，他引：1  

Ivan K. Bonev  Thomas Kerestedjian  Radostina Atanassova  Colin J. Andrew 《Mineralium Deposita》2002,37(6-7):614-629

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Comments on the paper by L.M. Lawrance and B.J. Griffin     

I. K. Bonev  I. Vesselinov 《Mineralium Deposita》1996,31(4):348-349

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Multiphase flow modeling with density functional method     

Oleg Dinariev  Nikolay Evseev 《Computational Geosciences》2016,20(4):835-856

This paper is a review of applications of density functional theory (DFT) in compositional hydrodynamics. The basic idea is representation of the entropy or the Helmholtz energy of the mixture as the functional depending on the molar densities of chemical components (density functional). The hydrodynamics is governed by local conservation laws of chemical components, momentum, and energy, while constitutive relations and boundary conditions are introduced in accordance with the explicit form of the density functional. The general ideas and the history of the DFT in compositional hydrodynamics are discussed. Then the DFT for multiphase multicomponent mixtures is presented including the exposition of the first principles, governing equations and constitutive relations, and explicit expressions of density functional depending on physical situation. The DFT-based numerical simulator is described, and several multiphase simulation results are presented to illustrate the scope and effectiveness of DFT: sessile drop with and without surfactant, droplet breakup in shear flow, and three-phase hydrodynamics with mobile solid phase. Also, two practical scenarios with multiphase simulations in micro-CT porous rock models are presented: two-phase immiscible water-oil flow and three-phase water-gas-condensate flow with phase transitions. All numerical results are obtained by essentially the same code; both the number of chemical components and the Helmholtz energy have been set up in accordance with physical situation.  相似文献   

Comment on Georgiev et al. “Structure and U–Pb zircon geochronology of an Alpine nappe stack telescoped by extensional detachment faulting (Kulidzhik area,Eastern Rhodopes,Bulgaria)     

Nikolay Bonev  Richard Spikings  Peter Marchev 《International Journal of Earth Sciences》2016,105(7):2161-2170

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State of the environment of urban and mining areas in the Selenga Transboundary River Basin (Mongolia Russia)     

Nikolay Kasimov  Natalia Kosheleva  Petr Gunin  Ilya Korlyakov  Olga Sorokina  Ivan Timofeev 《Environmental Earth Sciences》2016,75(18):1283

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Platinum-group minerals in the LG and MG chromitites of the eastern Bushveld Complex,South Africa     

Thomas Oberthür  Malte Junge  Nikolay Rudashevsky  Eveline de Meyer  Paul Gutter 《Mineralium Deposita》2016,51(1):71-87

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