Server hardware resources optimization for virtual desktop implementation

Considering the virtual desktop infrastructure implementation at the university this article discusses the problem of server hardware resources utilization. The possibility of applying the methods of linear programming to the problem of minimizing the necessary costs when selecting equipment is analyzed, linear objective function and constraints are suggested

Extending the lining life in circulatory vacuum units at OAO EVRAZ NTMK

Practical methods for extending the life of submersible tubes in vacuum chambers are considered. The structure of periclase-chromite components is studied. Refractories corresponding to optimal vacuum-chamber operation in the converter shop at OAO EVRAZ NTMK are selected. © 2013 Allerton Press, Inc

Hydrogen Removal in Circulating Vacuum Degasser under Conditions of PJSC "NLMK"

For high-quality steel smelting, stage-by-stage production is required, which has a complex of metallurgical units capable for producing products with high performance properties and low content of harmful impurities. One of the harmful impurities is hydrogen, so it is important to limit its content in the metal. To ensure the specified hydrogen content, the metal in the steel out-of-furnace treatment at Converter Shop No. 2 (CS-2) of PJSC "Novolipetsk Metallurgical Plant" ("NLMK") is subjected to vacuum treatment in a circulating vacuum degasser. Despite the prevalence of circulating vacuum derassers, theoretically, mechanism of hydrogen removal in these metallurgical units has been insufficiently studied. To increase efficiency of hydrogen removal, theoretical calculations were performed to remove it from the metal. There are several mechanisms for hydrogen removing: direct transfer of hydrogen from metal to the surrounding space; formation of gas bubbles in metal and their direct ascent; nucleation of hydrogen bubbles at the border of refractory wall and metal; removal of hydrogen by metal blowing with neutral gas (argon). It is shown that the main ways of hydrogen removal in a circulating vacuum degasser are direct transfer of hydrogen from metal to the surrounding space and blowing of melt with transporting gas. In the CS-2 of PJSC "NLMK", both ways are implemented at a circulating vacuum degasser. Vacuum pumps provide pressure in a vacuum chamber of less than 101.3 Pa (0.001 atm.). It promotes intensive removal of hydrogen from the metal surface. To ensure circulation of metal, transporting gas argon is supplied to the inlet pipe of the RH degasser, which also takes part in removal of dissolved gases by transferring hydrogen to neutral gas bubbles. Additionally, performed calculations have shown that the main way of degassing in conditions of CS-2 of PJSC "NLMK" is removal of hydrogen into the bubbles of carrier gas. © 2021 National University of Science and Technology MISIS. All rights reserved

DBSolve Optimum: a software package for kinetic modeling which allows dynamic visualization of simulation results

<p>Abstract</p> <p>Background</p> <p>Systems biology research and applications require creation, validation, extensive usage of mathematical models and visualization of simulation results by end-users. Our goal is to develop novel method for visualization of simulation results and implement it in simulation software package equipped with the sophisticated mathematical and computational techniques for model development, verification and parameter fitting.</p> <p>Results</p> <p>We present mathematical simulation workbench DBSolve Optimum which is significantly improved and extended successor of well known simulation software DBSolve5. Concept of "dynamic visualization" of simulation results has been developed and implemented in DBSolve Optimum. In framework of the concept graphical objects representing metabolite concentrations and reactions change their volume and shape in accordance to simulation results. This technique is applied to visualize both kinetic response of the model and dependence of its steady state on parameter. The use of the dynamic visualization is illustrated with kinetic model of the Krebs cycle.</p> <p>Conclusion</p> <p>DBSolve Optimum is a user friendly simulation software package that enables to simplify the construction, verification, analysis and visualization of kinetic models. Dynamic visualization tool implemented in the software allows user to animate simulation results and, thereby, present them in more comprehensible mode. DBSolve Optimum and built-in dynamic visualization module is free for both academic and commercial use. It can be downloaded directly from <url>http://www.insysbio.ru</url>.</p

Hydrogen Removal in Circulating Vacuum Degasser under Conditions of PJSC “NLMK”

For high-quality steel smelting, stagebystage production is required, which has a complex of metallurgical units capable for producing products with high performance properties and low content of harmful impurities. One of the harmful impurities is hydrogen, so it is important to limit its content in the metal. To ensure the specified hydrogen content, the metal in the steel outoffurnace treatment at Converter Shop No. 2 (CS2) of PJSC “Novolipetsk Metallurgical Plant” (“NLMK”) is subjected to vacuum treatment in a circulating vacuum degasser. Despite the prevalence of circulating vacuum degassers, theoretically, mechanism of hydrogen removal in these metallurgical units has been insufficiently studied. To increase efficiency of hydrogen removal, theoretical calculations were performed to remove it from the metal. There are several mechanisms for hydrogen removing: direct transfer of hydrogen from metal to the surrounding space; formation of gas bubbles in metal and their direct ascent; nucleation of hydrogen bubbles at the border of refractory wall and metal; and removal of hydrogen by metal blowing with neutral gas (argon). It is shown that the main ways of hydrogen removal in a circulating vacuum degasser are direct transfer of hydrogen from metal to the surrounding space and blowing of melt with transporting gas. In the CS2 of PJSC “NLMK”, both ways are implemented at a circulating vacuum degasser. Vacuum pumps provide pressure in a vacuum chamber of less than 101.3 Pa (0.001 atm). It promotes intensive removal of hydrogen from the metal surface. To ensure circulation of metal, transporting gas argon is supplied to the inlet pipe of the RH degasser, which also takes part in removal of dissolved gases by transferring hydrogen to neutral gas bubbles. Additionally, performed calculations have shown that the main way of degassing in conditions of CS2 of PJSC “NLMK” is removal of hydrogen into the bubbles of carrier gas. © 2021, Allerton Press, Inc

Calculation of sulfur removal in ladle furnace unit by means of ionic theory of slags

This article describes issues of sulfur removal in ladle furnace unit. First of all, metal desulfurization in ladle steel treatment units is achieved due to transition of sulfur to the slag phase. Coefficient of partition of sulfur between metal and slag is affected by sulfide capacity of slag, coefficient of activity of sulfur in the metal, oxidation potential of medium and reaction equilibrium constant of partition of sulfur between metal and slag. Temperature of liquid state in the ladle has significant impact on sulfide capacity of slag. Proposed calculation procedure based on provisions of ionic structure of slags allows evaluating a concentration of sulfur in steel on the basis of determination of coefficient of its partition between metal and slag. Optical basicity is suggested as criterion of refining property of slag, it has been shown that the amphoteric oxide Al2O3 is essential to calculation of this indicator. Its impact on sulfide capacity of slag is detected. © Published under licence by IOP Publishing Ltd

Применение ионной теории для расчета сульфидной емкости шлаков

The article considers the issues of sulfur removal in the ladle-furnace unit. The sulfur distribution coefficient depends on sulfide capacity of the slag, sulfur activity coefficient, oxidizing potential of the medium and equilibrium constant. The sulfide capacity CS of slags is one of the most important characteristics of refining capacity of the slags used in extra-furnace steel processing. One of the factors affecting the sulfide capacity is temperature. The formula was proposed showing the dependence of sulfide capacity on the optical basicity and temperature, in the temperature range of 1650 - 1400 °C and when the optical basicity Λ is not more than 0.75; the error of the presented formula does not exceed 6 %. The formula for calculating the optical basicity is proposed, which takes into account the influence of basic, acidic oxides and amphoteric oxide Al2O3 . It is shown that slags, completely consisting of a homogeneous phase, have an increased optical basicity of aluminum oxide. Heterogeneous slags have a reduced optical basicity of Al2O3 in comparison with homogeneous slags. Perhaps, this fact can be explained by the fact that in homogeneous slags there is a deficiency of the basic oxide CaO and in the conditions under consideration Al2O3 compound begins to exhibit more basic properties than acidic ones, thus, in homogeneous slags, the optical basicity of aluminum oxide is increased and approaches optical basicity of CaO oxide. Calculations carried out on the basis of real heats have shown that with an increase in the content of Al2O3 oxide in the slag, its optical basicity decreases. Known value of the optical basicity makes it possible to determine sulfide capacity of the slag, sulfur distribution coefficient between metal and slag, and, accordingly, final sulfur content in the metal. The research results have shown that it is advisable to apply the ionic theory of slags for the sulfide capacity determination. © 2021 National University of Science and Technology MISIS. All rights reserved

Sulfur partition by process stages of metallurgical production of JSC EVRAZ NTMK

The current level of development of the industry requires the manufacture of steel with high purity in relation to detrimental impurities. Sulfur is one of such impurities that significantly reduces the service properties, the content of which is strictly regulated in the finished product. Deep desulfurization may be achieved through development of cross-cutting technology of metal production as a single process including agglomeration and blast-furnace process and steelmaking. Sulfur partition by metallurgical process stages via conversion from raw materials of the blast-furnace process to steel continuously cast blank is studied in this work. It is shown that removal of sulfur from the half-finished product at the desulfurization plant will not provide the required sulfur content (less than 0.005 %) in the steel ingot. It is determined that the activity plan comprising treatment of the half-finished product at the desulfurization plant, smelting in the converter, treatment of steel at the ladle furnace unit and then in the vacuum vessel is required to obtain the final content of sulfur of less than 0.005%. © Published under licence by IOP Publishing Ltd