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71.
An effectiveness of the storm wave attenuation by protective piers in the Sevastopol Bay of the Black Sea is studied on the basis of numerical simulation using the SWAN spectral model. Analyzed are the parameters of waves generated by winds of four main directions as well as by the southern cyclone during the storm on November 11, 2007. It is obtained that waves from the northwest part of the Black Sea penetrate most intensively into the Sevastopol Bay in case of western wind and, to a lesser degree, in case of northern and southern winds. A protective effect of the piers is observed in the west part of the bay only and the wave attenuation near the southern coast is more significant than near the northern one. The area of the southern coast directly behind the southern pier is completely protected from the storm waves and, as moving away from the pier, the danger of intensive wave effect on the coast is kept.  相似文献   
72.
Processes of roiling, transport-diffusion, and deposition of fine disperse bottom sediments are studied in the northwestern shelf of the Black Sea in different synoptic situations connected with the passage of cyclones. Movement of atmospheric disturbances with velocities of 5 and 15 m/s along three trajectories typical of this region is considered. A nonlinear sigma-coordinate numerical model is used to calculate hydrodynamic and suspension concentration fields. The bottom areas, most sensitive to erosion, and the areas of maximum accumulation of depositions due to their sedimentation are determined. The change in suspension distribution in the surface layer with time is studied.  相似文献   
73.
Connection between ozone concentration and atmosphere circulation is investigated based on measurements at BEO station, peak Moussala (2,925 m a.s.l.), for the period 09 August 2006 to 29 January 2008. Ozone concentration data are collected with UV-analyzer “Environnement O3 42” and meteo data with weather station “Vaisala”. There are measurements of 7Be. Data from NOAA HYSPLIT model for particle trajectories are also used. Eight wind directions and three ranges of wind velocities are employed in the analysis. A comparison of ozone concentrations in upward and downward air transport according to HYSPLIT model is made. The number of cases with ozone concentration above 63 ppb has been counted. Mann–Whitney nonparametric test is employed as a basic statistical method. Correlation between atmosphere pressure and tropospheric ozone content is made. The same is done for 7Be and ozone. The main conclusion is that there is not any local or regional pollution effect detectable at peak Moussala, but most of the ozone measured is due to emissions of hydrocarbons and NO x over a larger region. There could be some regional sources of ozone building substances in southwest direction from peak Moussala. Air transported from the north quarter has higher ozone concentrations compared to the south quarter. In vertical direction, upward transport of air masses shows higher values of ozone concentration. Higher wind velocity is associated with low ozone concentrations at peak Moussala. The annual course of ozone concentration has summer maximum and winter minimum. There is right connection between air pressure and ozone concentration. The same is valid for the correlation between 7Be and ozone. Diurnal ozone course shows daytime maximum in winter and nighttime maximum in summer.  相似文献   
74.
We examine the use of two alternative techniques for assessing the redistribution volumes of sorbed 137Cs within the upper components of the fluvial network, based on the concept of catchment as a lithodynamical system. In terms of one of them, we made a substantive analysis of changes in reserves on accumulative positions where the 137Cs distribution curves showed a significant increase in radionuclide content levels. We carried out a typization o the accumulation surfaces in order to extrapolate data, obtained for a group of soil profiles, to the territory of the entire catchment and to make a direct assessment of the increases in accumulation. An alternative technique was used to assess the volumes of accumulated sediment loads on accumulative positions by analyzing the 137Cs distribution curves, and to correlate with denudation zones in the drainage area under consideration. Values of the wash-out rates for the period 1986–2012 have been obtained, which are necessary for the formation of the accumulative layer observed. We calculated the volume of 137Cs swept away during 26 years after the Chernobyl accident, based on information regarding the volumes of initial reserves in the denudation zones and a correlation between the erosion rate and a specific reduction in reserves. It is established that the technique on the basis of analyzing the wash-out zones featuring high economical efficiency can be used in assessing 137Cs migration for larger territories with relatively low labor-consuming effort.  相似文献   
75.
There are a number of serious problems connected with building and repairing water-retaining elements in embankment dams in cold regions. One of them is the difficulty in finding inexpensive clay materials with the necessary structural properties and using them in the winter. Another is the cracks that appear in the upper part of a dam when the core freezes to the banks, and leakage along the cracks threatens to destroy the dam. Still another is the process of erosion at the bottom of the core which may occur through fissures in the rock foundation of a dam and in transport constructions. Also, the behaviour of water-retaining elements during earthquakes is unreliable. All of these problems can be solved by using ice- and cryogel-soil composites created by cryotropic gel formation (CGF). Our laboratory investigations demonstrate that the materials proposed for water-retaining elements have the necessary permeable, plastic, thermophysical, and strength properties to solve all of these problems. Certain constructions of water-retaining elements which may prove to be both safe and cost-effective are proposed. However, these ice- and cryogel-soil composites need to be field-validated before they are used in dams and transport structures in cold regions.  相似文献   
76.
The composition and origin of the Callovian–Oxfordian deposits of the Sudak Bay were characterized on the basis of the generalization and analysis of our own results, as well as published and unpublished data. The botanical future was first implemented for the geological mapping of the Oxfordian deposits.  相似文献   
77.
Detrital zircons (DZs) from arkose sandstones of the Upper Riphean Zilmerdak Formation (Southern Urals) yielded ages in the range of 3039–964 Ma. Grains with Late Karelian and Early and Middle Riphean ages compose 35, 34, and 26% of the total number of the analyzed zircons, respectively. This is similar to the age spectra of the Vendian sandstones (Asha Group), but it differs significantly from the age distribution typical of the Riphean stratotype sandstones.  相似文献   
78.
Despite the long history of research, the presence of Precambrian complexes in the West Siberian basement has not been proven. The Tyn'yarskaya 100 and Tyn'yarskaya 101 wells were drilled in the Vakh–Elogui interfluve, in the eastern West Siberian Plate (eastern Khanty-Mansi Autonomous District). At a depth of 1790 m, they stripped a rhyolite extrusion, which graded into A-type alkali granitoids with rare-metal and REE mineralization (thorite, thorogummite, pitchblende, REE-carbonates, chevkinite, and others) downsection. This volcanoplutonic complex is Early Permian (K–Ar age, ~ 270 Ma; Rb–Sr age, 275.7 Ma; Sm–Nd age, 276 Ma; U–Pb age, 277 Ma). Some zircon grains from granites are much older (2049 ± 23 Ma, SHRIMP II), suggesting a relationship between the Early Permian granitic magma and the ancient matter. This might have been a granite-metamorphic basement, the partial melting of which produced the Tyn'yar rhyolite–granite body. The Sm–Nd model ages also suggest the participation of a Precambrian substratum in the formation of the rocks under study. Thus, it is quite possible that the Tyn'yar area is underlain by a Proterozoic (~ 2 Ga) sialic basement, which is an edge of the Siberian Platform thinned by Late Proterozoic–Early Paleozoic rifting and extension.  相似文献   
79.
The analysis of the concentrations and distribution of mercury in bottom sediments of marginal seas in northeastern Asia revealed that its maximum contents are characteristic of areas with an active geodynamic regime and some areas of the Amur Bay in the Sea of Japan subjected to anthropogenic impact. The geochemical associations of mercury with other chemical elements and its background concentrations in bottom sediments of these sea basins are defined.  相似文献   
80.
The article presents a review of scientific problems and methods of ultraviolet astronomy, focusing on perspective scientific problems (directions) whose solution requires UV space observatories. These include reionization and the history of star formation in the Universe, searches for dark baryonic matter, physical and chemical processes in the interstellar medium and protoplanetary disks, the physics of accretion and outflows in astrophysical objects, from Active Galactic Nuclei to close binary stars, stellar activity (for both low-mass and high-mass stars), and processes occurring in the atmospheres of both planets in the solar system and exoplanets. Technological progress in UV astronomy achieved in recent years is also considered. The well advanced, international, Russian-led Spektr-UV (World Space Observatory—Ultraviolet) project is described in more detail. This project is directed at creating a major space observatory operational in the ultraviolet (115–310 nm). This observatory will provide an effective, and possibly the only, powerful means of observing in this spectral range over the next ten years, and will be an powerful tool for resolving many topical scientific problems.  相似文献   
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