Current trends of ice coverage changes in the Franz Josef Land Archipelago area

Doklady Earth Sciences - The data on the ice distribution in the Franz Josef Land Archipelago area during the 2010/2011 and 2014/2015 ice seasons depending on climate oscillations are presented...     

Determining basic characteristics of stars from evolutionary computations

A technique for determining a star’s radius from its atmospheric characteristics (effective temperature, surface gravity, and metallicity) is realized based on modernmodel computations of the stellar internal structure and evolution. The atmospheric characteristics can also be used to find the mass and luminosity of the star. The star’s rate of evolution and the initial mass function are taken into account when determining the stellar characteristics, increasing the correctness of the results. Computations of stellar evolution of with and without the stellar rotation taken into account make it possible to remove ambiguity due to missing data on the star’s rotational velocity. The results are checked and uncertainties estimated using stars occupying two heavily populated regions in the Hertzsprung–Russell diagram that have been well studied using various methods: the main sequence and red giant branch. Good agreement with the observations is achieved; there are almost no systematic deviations of the derived point estimates of the fundamental characteristics. The metallicities of the individual components of eclipsing variable stars are estimated using observational data on for such stars displaying lines of both components in their spectra. These metallicities were determined as a function of the stellar masses in a way that eliminates systematic deviations in the derived fundamental characteristics.     

Geographical factors of the abundance of flora in Russian cities

Doklady Earth Sciences - An analysis of data on the species abundance of flora in 89 cities (urban flora) of the Russian Federation facilitated determination of its main factors. It has been...     

Diagnostic modelling of within-water processes in reservoirs

The objectives of diagnostic calculations using mathematical models of reservoirs are formulated. The structure of a box hydrological model GMV-MGU is described, and the results of calculation of daily water balance, internal heat exchange structure, and heat balance of individual areas in the Mozhaisk and Rybinsk reservoirs are given. First results of calculation of variations in mean daily phytoplankton biomass in the near-dam pool of a weakly eutrophic water body in period of spring (diatoms) and summer (blue-green) blooming are presented.     

On the evaluation of displacement and deformation in tidal waves according to digital records of STS-2 and KSESh-R seismometers

A procedure for eliciting displacements in tidal waves from seismograms of broadband velocimeters like STS-2 and KSESH-R and the evaluation conversion of these displacements into vertical or volumetric deformation is proposed.     

Bottom sediments of the oldest reservoir in Moscow region

The methodological features and results of two soil surveys of the Senezh Reservoir carried out in 1992 and 2006 as a part of multidisciplinary limnological studies of this large recreation water body with the aim to monitor its ecological state and prepare recommendations for water protection measures are analyzed     

Short contribution: Buried Canopic channel identified near Egypt's Nile delta coast with radar (SRTM) imagery

Shuttle Radar Topography Mission (SRTM) data, with ground‐based geologic investigations, define the geographic position of the relict Canopic channel in Egypt's NW Nile delta. Two sinuous channel segments south of Abu Qir Bay are observed on a radar image: a more sinuous trace (36 km in length) west of Idku lagoon, and an eastern one (˜20 km), reaching the lagoon's southeast corner. Sediment cores recovered along channel traces show sand‐rich deposits (to > 4 m thick) beneath the surface, in contrast with silty muds in areas away from channels. Historic and archaeological findings indicate that the Ptolemaic Roman city of Schedia once lay directly along the Canopic that channeled water from the 3rd to 2nd centuries B.C. until ˜5th century A.D., after which Nile water was displaced to the east via Bolbitic and, later, Rosetta branches. Identification of buried, but well‐defined, Canopic channels provides baselines for renewed archaeological exploration in this delta sector. © 2006 Wiley Periodicals, Inc.     

Cryogenic Core Collection (C3) from Unconsolidated Subsurface Media

We evaluated tools and methods for in situ freezing of cores in unconsolidated subsurface media. Our approach, referred to as cryogenic core collection (C₃), has key aspects that include downhole circulation of liquid nitrogen (LN) via a cooling system, strategic use of thermal insulation to focus cooling into the core, and controlling LN back pressure to optimize cooling. Two cooling systems (copper coil and dual‐wall cylinder) are described. For both systems, the time to freeze a single 2.5‐foot (76‐cm) long by 2.5‐inch (63‐mm) diameter core is 5 to 7 min. Frozen core collection rates of about 30 feet/day (10 m/day) were achieved at two field sites, one impacted by petroleum‐based light nonaqueous phase liquids (LNAPLs) and the other by chlorinated solvents. Merits of C₃ include (1) improved core recovery, (2) potential control of flowing sand, and (3) improved preservation of critical sediment attributes. Development of the C₃ method creates novel opportunities to characterize sediment with respect to physical, chemical, and biological properties. For example, we were able to resolve water, LNAPL, and gas saturations above and below the water table. By eliminating drainage of water, gas and LNAPL saturations in the range of 6 to 23% and 1 to 3% of pore space, respectively, were measured in LNAPL‐impacted intervals below the water table.     

The Effect of Aggregation of Impurity Nitrogen on Diamond X-Ray Luminescence

Two samplings of 65 diamond crystals divided by the intensity of a slow X-ray luminescence component are studied from the Arkhangel’skaya and Karpinskogo-1 pipes. IR and EPR spectroscopies revealed a relationship between the nitrogen A and P2 centers of the diamonds and the presence of a slow X-ray luminescence component. Its absence in most diamonds with high content of P1 (C) centers is explained by the low number of A and P2 centers.