On the Variability of Southern Ocean Front Locations Between Southern Brazil and the Antarctic Peninsula

A 4-year expendable bathythermograph data set (1984–1987) from the area between southern Brazil and the Antarctic Peninsula provides information on the interannual variability of front locations. Two boundaries of subtropical water at different depths are identified north and south of the Brazil Current-Falkland (Malvinas) Current confluence zone. The northern Subtropical Front is displaced over a large part of the Argentine Basin from one observational period to the other. The shallow southern Subtropical Front appears fixed to the Falkland Escarpment. The Polar Front and Subantarctic Front locations do not vary much, except for one case where a cold core eddy in the Polar Frontal Zone causes a large northward displacement of the Subantarctic Front

Variability of dense water formation in the Ross Sea

The paper presents results from a model study of the interannual variability of High Salinity Shelf Water (HSSW) properties in the Ross Sea.Salinity, potential temperature and volume of HSSW formed in the western Ross Sea show oscillatory behaviour at periods of 5-6 and 9 years superimposed on long-term fluctuations.While the shorter oscillations are induced by wind variability, variability on the scale of decades appears to be related to air temperature fluctuations.At least part of the strong decrease of HSSW salinities deduced from observations for the period 1963-2000 is shown to be an aliasing artefact due to an undersampling of the periodic signal.While sea ice formation is responsible for the yearly salinity increase that triggers the formation of High Salinity Shelf Water, interannual variability of net freezing rates hardly affects changes in the properties of the resulting water mass.Instead, results from model experiments indicate that the interannual variability of dense water characteristics is predominantly controlled by variations in the shelf inflow through a sub-surface salinity and a deep temperature signal.The origin of the variability of inflow characteristics to the Ross Sea continental shelf can be traced into the Amundsen and Bellingshausen Seas.The temperature anomalies are induced at the continental shelf break in the western Bellingshausen Sea by fluctuations of the meridional transport of Circumpolar Deep Water with the eastern cell of the Ross Gyre.Upwelling in the centre of this gyre carries the signal into the surface layer where it causes anomalies of brine release near the sea ice edge in the Amundsen Sea, which results in a sub-surface salinity anomaly.With the westward flowing coastal current, both the sub-surface salinity and deep temperature signals are advected onto the Ross Sea continental shelf.Convection carries the signal of salinity variability into the deep ocean, where it interacts with Modified Circumpolar Deep Water upwelled onto the continental shelf as the second source water mass of HSSW.Sea ice formation on the Ross Sea continental shelf thus drives the vertical propagation of the signal rather than determining the signal itself

Physical and chemical calculations of steelmaking processes and predictive models for the production of clean steels

Ботников Сергей Анатольевич, канд. техн. наук, докторант кафедры материаловедения и физико-химии материалов, Южно-Уральский государственный университет, Челябинск, Россия; [email protected]. Sergey A. Botnikov, Cand. Sci. (Eng.), Doctoral student of the Department of Materials Science and Physical Chemistry of Materials, South Ural State University, Chelyabinsk, Russia; [email protected].Приведены результаты физико-химических расчётов сталеплавильных процессов для производства чистых сталей, раскисленных алюминием. Рассмотрен подход совершенствования технологии производства чистых сталей, включая элементы математических и термодинамических моделей, а также алгоритмические подходы для построения статических моделей с применением технологии машинного обучения, позволяющие повышать эффективность в сталеплавильных технологиях. С целью получения прикладного применения представленного подхода необходима предварительная подготовка массива данных, а также осуществление интерпретации результатов машинного обучения, основывающихся на фундаментальных законах и физико-химических процессах, протекающих в сталеплавильном производстве. В результате выполненных термодинамических расчётов в программе STM были разработаны мероприятия для производства чистых сталей. На примерах производства тонкого сляба, сортовых и блюмовых заготовок выполнен поиск и подтверждение значимых технологических параметров в формировании сталеплавильных дефектов из-за неметаллических включений с применением методов углубленной аналитики и машинного обучения. The results of physicochemical calculations of steelmaking processes for the production of clean steels deoxidized with aluminum are presented. An approach is considered to improve the technology of clean steel production, including elements of mathematical and thermodynamic models, as well as algorithmic approaches for building static models using machine learning technology, which make it possible to increase efficiency in steelmaking technologies. In order to obtain an applied application of the presented approach, it is necessary to prepare a data array in advance, as well as to interpret the results of machine learning, based on the fundamental laws and physical and chemical processes occurring in steelmaking. As a result of the thermodynamic calculations performed in the STM program, measures were developed for the production of clean steels. On the examples of the production of thin slabs and billets, bloom, the search and confirmation of significant technological parameters in the formation of steel-making defects due to non-metallic inclusions was carried out using methods of in-depth analytics and machine learning

Antarctic Circumpolar Current frontal system in the South Atlantic: monitoring using merged Argo and animal-borne sensor data

We describe large-scale features of the Antarctic Circumpolar Current (ACC) in the Atlantic part of the Southern Ocean by merging Argo data and data obtained by novel animal-borne CTD sensors. Twenty one of these CTD-Satellite Relay Data Loggers (CTD-SRDLs) were attached to Southern elephant seals (Mirounga leonina) on South Georgia. The merged data yield unified gridded hydrogaphic fields with high temporal and spatial resolution, enabling the determination of features absent in each of the data sets separately. The structure and variability of the frontal field revealed by this data set were compared with those in daily quarter-degree, optimally interpolated sea surface temperature fields and fields of weekly gridded sea level anomaly. In general, the frontal positions derived using our data set are in agreement with previous work, especially where the pathways are constrained by topography, e. g., at the North Scotia Ridge and the South Scotia Ridge. However, with the improved temporal and spacial resolution provided by the CTD-SRDLs, we were able to observe some novel features. All frontal positions are more variable than previously indicated across the Scotia Sea and west of the Mid-Atlantic Ridge on seasonal time scales. The merged data set shows the temporal variability of the Southern ACC Front (SACCF) north of South Georgia and in its position east of the island, where the SACCF lies further north than has been suggested in previous work. In addition, the Subantarctic Front crosses the Mid-Atlantic Ridge about 400 km further north when compared to previous work

Impact of the tundish metal wiring geometry and casting process parameters on the running of billet continuous casting machine

Ботников Сергей Анатольевич, кандидат технических наук, докторант кафедры физической химии, Южно-Уральский государственный университет. Тел.: 8(922)203960. E-mail: [email protected]. S.A. Botnikov, South Ural State University, Chelyabinsk, Russian Federation, [email protected]Стабильная работа сортовой установки непрерывной разливки стали (УНРС) в первую очередь подразумевает правильный запуск всех ручьев. Проблема со стартом ручьев кроется не только в общеизвестных факторах, но, и в незначительных мелочах. Представлено влияние геометрии металлопроводки промежуточного ковша и стартовых технологических параметров УНРС, а также показаны пути решения стартовых переливов и стартовых прорывов под кристаллизатором на сортовых УНРС. Статья написана автором на основе собственного опыта освоения стопорной разливки на сортовых УНРС на ОАО «ЧМК» и ОАО «ПНТЗ». Stable running of the billet continuous casting machine (CCM) in the first place implies a correct startup of all casting strands. The challenge of the strands startup lies not only in commonly known facts, but also in insignificant details. The paper describes the impact of the tundish metal wiring geometry and starting process parameters of CCM as well as solutions for startup overflows and startup breakouts under the mould in the billet CCM. The paper is written on the basis of the author’s own experience in the integration of the nozzle casting in the billet CCMs in OJSC “ChMP” and OJSC “PNTZ”