Using optical fibers (OF) to control the stress-strain state of steel structures subject to fatigue failure

The article presents the results related to developing and practical testing the method of monitoring the stress strain state of steel structures of mine hoisting machines. Certain positive properties of optical fibers make it possible to use them for measuring the stress-strain state of steel structures. An optical fiber of the ITU-T G.652.D standard is used as a sensor. The analysis and review of the current state of development of fiber-optic conductors is performed. The proposed method of non-destructive testing the stress-strain state of metal structures is capable of providing continuous measurements in real time. The proposed method is universal and suitable for monitoring the stress-strain state of any metal structures subject to fatigue failure

METHODOLOGY FOR EFFECTIVE DETERMINATION OF ROCK JOINTING IN CALCULATION OF OPEN PIT EDGES

ABSTRACT This paper is intended to increase the reliability of measuring the stability of open pit edges by developing a methodology for remote determination of rock jointing. The study employed a number of methods: analysis and summarization of results of previous studies, including those presented in regulatory and methodological documents; instrumental studies in field conditions, mathematical processing of experimental data results, computer modeling of stress strain behavior of the near-edge massif. The paper proposes the scheme to account for rock jointing by using digital photo survey in order to specify the stability parameters of edges, with the remote method to study jointing tested at the Novosergeyevskiy and Pechurki open pits. The practical value consists in developing calculation methods for stability of open pit edges by accounting for rock jointing. The obtained results can be used at design mining companies, educational institutions and at open pits (quarries), as well as at specialized organizations studying rock jointing properties

Экспериментальные исследования переноса ледяного шлама воздухом при бурении снежно-фирновой толщи

The snow-firn layer of the glaciers of Antarctica and Greenland contains data on the composition of the atmosphere in the past, volcanic eruptions, forest fires, anthropogenic pollution, and many other unique information. Nowadays, core drilling methods are widely used for sampling the snow-firn layer. Due to numerous complications (loss of air circulation, drill bit sticking, ice balling up, etc.), air ice drilling is not wide spread, yielding in productivity and reliability to thermal and auger drilling methods. However, core barrel drilling with reverse bottom-hole air circulation is a promising technology for drilling the glaciers of Antarctica and Greenland. However, core drilling with reverse bottom-hole air circulation is a promising technology for drilling Antarctic and Greenland glaciers. The authors suggest that this technology, if successfully implemented, will significantly exceed the currently used methods of drilling the upper layers of the glacier. Taking into account the failures of previous projects of core drilling with air, it was decided to conduct research in the conditions of Central Antarctica in order to substantiate the design parameters of the new drill. During 67th Russian Antarctic Expedition (RAE) experimental studies of ice cuttings air transportation while drilling of the snow-firn layer were conducted at Vostok station. In the course of the experimental studies, the VK-22 borehole was drilled to a depth of 30 m with full core and ice cuttings sampling. According to the selected probes, the dependences of the change in the density of the snow-firn layer, bulk density and fractional composition of ice cuttings on the depth of occurrence were established. By using the experimental facility, the suspension velocity (critical speed in drilling) of ice particles of various sizes and shapes was found for the first time. Directions for further research and ways to improve the experimental facility are proposed, which are planned to be implemented in the season of the 68th RAEВ целях разработки технологии бурения снежно-фирновой толщи с обратной призабойной циркуляцией воздуха на станции Восток проведены экспериментальные исследования. Установлена динамика изменения характеристик ледяного шлама, таких как: фракционный состав, насыпная плотность, форма и скорость витания в зависимости от параметров снежно-фирнового горизонта, в том числе от распределения плотности массива по глубине

Biomass of Scyphozoan Jellyfish, and Its Spatial Association with 0-Group Fish in the Barents Sea

An 0-group fish survey is conducted annually in the Barents Sea in order to estimate fish population abundance. Data on jellyfish by-catch have been recorded since 1980, although this dataset has never been analysed. In recent years, however, the ecological importance of jellyfish medusae has become widely recognized. In this paper the biomass of jellyfish (medusae) in 0–60 m depths is calculated for the period 1980–2010. During this period the climate changed from cold to warm, and changes in zooplankton and fish distribution and abundance were observed. This paper discusses the less well known ecosystem component; jellyfish medusae within the Phylum Cnidaria, and their spatial and temporal variation. The long term average was ca. 9×108 kg, with some years showing biomasses in excess of 5×109 kg. The biomasses were low during 1980s, increased during 1990s, and were highest in early 2000s with a subsequent decline. The bulk of the jellyfish were observed in the central parts of the Barents Sea, which is a core area for most 0-group fishes. Jellyfish were associated with haddock in the western area, with haddock and herring in the central and coastal area, and with capelin in the northern area of the Barents Sea. The jellyfish were present in the temperature interval 1°C<T<10°C, with peak densities at ca. 5.5°C, and the greatest proportion of the jellyfish occurring between 4.0–7.0°C. It seems that the ongoing warming trend may be favourable for Barents Sea jellyfish medusae; however their biomass has showed a recent moderate decline during years with record high temperatures in the Barents Sea. Jellyfish are undoubtedly an important component of the Barents Sea ecosystem, and the data presented here represent the best summary of jellyfish biomass and distribution yet published for the region

The Barents and Chukchi Seas: Comparison of two Arctic shelf ecosystems

This paper compares and contrasts the ecosystems of the Barents and Chukchi Seas. Despite their similarity in a number of features, the Barents Sea supports a vast biomass of commercially important fish, but the Chukchi does not. Here we examine a number of aspects of these two seas to ascertain how they are similar and how they differ. We then indentify processes and mechanisms that may be responsible for their similarities and differences.Both the Barents and Chukchi Seas are high latitude, seasonally ice covered, Arctic shelf-seas. Both have strongly advective regimes, and receive water from the south. Water entering the Barents comes from the deep, ice-free and "warm" Norwegian Sea, and contains not only heat, but also a rich supply of zooplankton that supports larval fish in spring. In contrast, Bering Sea water entering the Chukchi in spring and early summer is cold. In spring, this Bering Sea water is depleted of large, lipid-rich zooplankton, thus likely resulting in a relatively low availability of zooplankton for fish. Although primary production on average is similar in the two seas, fish biomass density is an order of magnitude greater in the Barents than in the Chukchi Sea. The Barents Sea supports immense fisheries, whereas the Chukchi Sea does not. The density of cetaceans in the Barents Sea is about double that in the Chukchi Sea, as is the density of nesting seabirds, whereas, the density of pinnipeds in the Chukchi is about double that in the Barents Sea. In the Chukchi Sea, export of carbon to the benthos and benthic biomass may be greater. We hypothesize that the difference in fish abundance in the two seas is driven by differences in the heat and plankton advected into them, and the amount of primary production consumed in the upper water column. However, we suggest that the critical difference between the Chukchi and Barents Seas is the pre-cooled water entering the Chukchi Sea from the south. This cold water, and the winter mixing of the Chukchi Sea as it becomes ice covered, result in water temperatures below the physiological limits of the commercially valuable fish that thrive in the southeastern Bering Sea. If climate change warms the Barents Sea, thereby increasing the open water area via reducing ice cover, productivity at most trophic levels is likely to increase. In the Chukchi, warming should also reduce sea ice cover, permitting a longer production season. However, the shallow northern Bering and Chukchi Seas are expected to continue to be ice-covered in winter, so water there will continue to be cold in winter and spring, and is likely to continue to be a barrier to the movement of temperate fish into the Chukchi Sea. Thus, it is unlikely that large populations of boreal fish species will become established in this Arctic marginal sea. © 2012 Elsevier B.V

Method of Computing Open Pit Slopes Stability of Complicated-Structure Deposits

In substantiation of the parameters of stable open pit slopes of complicated-structure deposits it is necessary to take into account a number of natural and anthropogenic conditions of the open pit side masses, such as: lithological heterogenity, plicative and disjunctive tectonic broken state, rocks laminated structure, form of the open pit side, hydro-geological conditions of the deposit development, the mining-transport equipment loading effect, etc. In the article there is suggested a solution of this problem consisting in the improving of numerical-analytical method of professor P.S. Shpakov, whose advantage is the accounting if stresses acting on the elementary ground based on integrated effect of all the acting factors. The essence of the solution con-sists in the following: with a unified algorithm of realization (numerical solu-tion, iteration method) every time there is built a new analytical formula of the limit equilibrium corresponding to the concrete mining-technical and mining-geological conditions permitting to establish the mechanism of the possible de-forming of open pit slopes

Water fluxes through the Barents Sea

The physical oceanographic conditions in the Barents Sea depend mainly on the variability in the Atlantic inflow from the Norwegian Sea and the inflow of Arctic water from the Kara Sea and the Arctic Ocean. The transport out of the Barents Sea consists of transformed Atlantic water to the Arctic Ocean and also partly to the Norwegian Sea. To describe the water balance, good estimates of the volume transports between the different seas are needed. By means of available literature, some current measurements and ocean modelling, the present paper describes the water fluxes through the Barents Sea. Russian scientists have calculated the geostrophical transport of the Atlantic current, and found a clear seasonal variation with maximum flow during wintertime. Current measurements, carried out in an array in the northeastern Barents Sea, confirm this seasonality. The outflow varies from 1 to 3 Sv with maximum during the cold season. The results from a wind-driven numerical model of the Atlantic inflow also show a clear interannual variability. Both the seasonal and interannual variability seem to be linked to the atmospheric pressure, and the results clearly indicate the highest flow of water when the atmospheric pressure is low. Based on available literature from all the different in/ out-flow areas, we try to make a balanced budget for the Barents Sea throughflow. The results indicate an average ingoing and outgoing transport of approximately 4 Sv, of which the throughflow of Atlantic water contributes the half

Current measurements in the northeastern Barents Sea

The Institute of Marine Research (IMR) in cooperation with Knipowich Polar Reseach Institute of Marine Fisheries and Oceanography (PINRO), Murmansk, started in autumn 1991 a current measurement program in the strait between Novaya Zemlya and Frans Josef Land. The objectives of the project were: - to study water masses and the general circulation in the area - to estimate the outflow of dense bottom water from the Barents Sea - to obtain data for boundary conditions for numerical models. During late September and the beginning of October 1991, five moorings, with all together 20 current meters were deployed along one section across the strait. The moorings were recovered one year later. During the period of deployment and recovery, hydrographical investications were carried out along five sections in the area. In addition, some other hydrographic observations were carried out. The present paper describes the results from the hydrographic observations and the current measurements carried out from the end of September 1991 to early September 1992. The results confirm the assumption that this is the main outflow area of water masses from the Barents Sea. The results indicate a marked seasonal variability in the outflow, varying from 0.7 to 3.2 Sv, and with maximum during early winter. At some locations the current is extremely stable, and current stability above 90% is observed. The main driving force of the current is probably the density field. There is also an extremely good accordance between the variability in air pressure over the Barents Sea and the varibility in the current conditions. Low pressure seems to create a strong circulation in the Barents Sea, while high pressure periods seems to decrease the circulation