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

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

MONITORING OF THE UNDERMINED TERRITORIES OF KARAGANDA COAL BASIN ON THE BASIS OF SATELLITE RADAR INTERFEROMETRY

In the Karaganda coal basin, mines are located in close proximity to each other and to the city of Karaganda and ongoing mining operations are accompanied by a dangerous process of settling the earth's surface and monitoring are essential for the region's econ-omy. Underground mining leads to the formation of voids in the rock mass, which cause displacement of the earth surface. This paper demonstrates an innovative use of the integrated approach for monitoring on the example of Karaganda coal basin, which includes estimation of the rock mass displacement using leveling profile lines and satellite radar interferometry. It is proved that satellite radar interferometry provides reliable results of surface subsidence measurements in mining areas and can be used for con-sidered sort of monitoring

Atlantic water flow through the Barents and Kara Seas

The pathway and transformation of water from the Norwegian Sea across the Barents Sea and through the St. Anna Trough are documented from hydrographic and current measurements of the 1990s. The transport through an array of moorings in the north-eastern Barents Sea was between 0.6 Sv in summer and 2.6 Sv in winter towards the Kara Sea and between zero and 0.3 Sv towards the Barents Sea with a record mean net flow of 1.5 Sv. The westward flow originates in the Fram Strait branch of Atlantic Water at the Eurasian continental slope, while the eastward flow constitutes the Barents Sea branch, continuing from the western Barents Sea opening.About 75% of the eastward flow was colder than 0°C. The flow was strongly sheared, with the highest velocities close to the bottom. A deep layer with almost constant temperature of about -0.5°C throughout the year formed about 50% of the flow to the Kara Sea. This water was a mixture between warm saline Atlantic Water and cold, brine-enriched water generated through freezing and convection in polynyas west of Novaya Zemlya, and possibly also at the Central Bank. Its salinity is lower than that of the Atlantic Water at its entrance to the Barents Sea, because the ice formation occurs in a low salinity surface layer. The released brine increases the salinity and density of the surface layer sufficiently for it to convect, but not necessarily above the salinity of the Atlantic Water. The fresh-water west of Novaya Zemlya primarily stems from continental runoff and at the Central Bank probably from ice melt. The amount of fresh water compares to about 22% of the terrestrial fresh water supply to the western Barents Sea. The deep layer continues to the Kara Sea without further change and enters the Nansen Basin at or below the core depth of the warm, saline Fram Strait branch. Because it is colder than 0°C it will not be addressed as Atlantic Water in the Arctic Ocean.In earlier decades, the Atlantic Water advected from Fram Strait was colder by almost 2K as compared to the 1990s, while the dense Barents Sea water was colder by up to 1K only in a thin layer at the bottom and the salinity varied significantly. However, also with the resulting higher densities, deep Eurasian Basin water properties were met only in the seventies. The very low salinities of the Great Salinity Anomaly in 1980 were not discovered in the outflow data. We conclude that the thermal variability of inflowing Atlantic water is damped in the Barents Sea, while the salinity variation is strongly modified through the fresh water conditions and ice growth in the convective area off Novaya Zemlya

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

Exploiting the metallurgical throughput-recovery relationship to optimise resource value as part of the production scheduling process

A single process plant throughput rate to achieve a certain recovery at a certain cost is often assumed over the life of a resource project for strategic planning purposes. The process plant throughput-recovery relationship that exists for each ore type can and should be exploited for the purpose of creating additional economic value within the resource plan. This paper investigates the impact on Net Present Value (NPV) of strategic resource plans when allowing a fluctuating process plant throughput rate over the life of a base metals operation in comparison to only considering a single fixed throughput rate for a given plant size configuration. The metallurgical throughput-recovery relationship is confirmed as being an important factor in planning the extraction of the resource to feed a given process plant of fixed size since this impacts heavily upon the production schedule and therefore the NPV of the project. Mathematical programming to better aid the decision making process is investigated in comparison to traditional manual approaches to thus help determine the best throughput rate to use in each period. Results suggest that it would seem reasonable to expect an increase of around 4.0% in NPV when allowing a fluctuating process plant throughput rate over a single fixed throughput rate over the life of a midsize underground operation when using a mathematical programming approach