188 research outputs found
Competency model for science and technology (S&T) personnel for the iron and steel industry
The article presents the competency model for S&T personnel for the iron and steel industry. The study performed has made it possible to determine a cluster of competencies required for innovative development of production involving development of energy-efficient technologies and high-performance steels. The results of the performed analysis have shown that for highly qualified professionals it is not sufficient just to have professional knowledge and demonstrate personal efficiency and ability to work in a team. They should also have professional engineering excellence skills, management skills and should be innovation-focused
Chatter prevention in stands of continuous cold rolling mills
The article states new results of the theoretical and applied research on prevention of chatter in stands of continuous cold rolling mills. It was found that chatter occurs under those process conditions, which involve violation of a condition of strip rolling with tension because of ongoing change of the process state, when the process proceeds now with tension and now with pushing because of variation of strip volumes per second in a negative or positive range of values. It is demonstrated that it is possible to influence effectively the difference of strip volumes per second and prevent chatter by decreasing reduction in a stand subject to chattering and simultaneously increasing reduction in adjacent stands, and also by changing the ratio of rolling speeds in these stands of the mill. This has led to development of process conditions for thin steel strip rolling on the 5-stand mill 1700 of PAO Severstal, enabling rolling speed increase and process stabilization
Methodology of design of the thin steel strip cold rolling energy efficient technology
The article states basic principles of the methodology of design of the thin steel strip production energy efficient technology, according to which the design process is structurally divided into seven interrelated modules of certain functions. Implementation of the represented approach resulted in the efficient technical mode of rolling providing reduction of overall power consumption subject to compliance with the requirements to quality parameters of the strip
Thermal expansion of a lead sulfide nanofilm
The thermal expansion of a lead sulfide nanofilm produced by chemical bath deposition was determined by X-ray diffraction (XRD). The thickness of the synthesized film was about 100 nm, and the average size of the coherent scattering regions as determined from XRD was about 40 nm. The lattice constant of the PbS nanofilm was measured as a function of the annealing temperature from 293 to 473 K and as a function of the annealing time at a constant temperature of 423 K. The thermal expansion coefficient derived was found almost twice as large as that for coarse-grained PbS. © 2013 Elsevier B.V. All rights reserved. All rights reserved
Dynamic model of cold strip rolling
A dynamic model of the cold rolling process at the continuous rolling mill that combines the model of the electromechanical system and the model of the deformation zone has been developed. The paper presents the results of the study of kinematic parameters, force and energy parameters of the deformation zone with regard to the fluctuating nature of the process variables and to the dynamic processes running in the electromechanical system. It is shown that the variations in the stated parameters are of fluctuating unsteady nature, which has an adverse effect on operation of equipment and quality of finished products
Evaluation of power losses during stochastic changes in the current of the main drives of cold rolling mills
This paper presents the analysis of the adverse impact of the current oscillations on electric power losses in the manufacture of flat rolled products. The results of mathematical processing of experimental data for the study of the influence of transient processes in the cold rolling mill electromechanical systems on the rate of power losses during rolling are discussed. The negative effect caused by power losses has been evaluated and focus areas to reduce the operational costs have been identified. In addition, technical measures aimed at minimizing oscillation processes during rolling have been proposed
The study of infl uence of work rolls vibration during cold rolling on the quality of steel strip surface
The article represents the results of the study of work rolls vibration influence on the quality of cold rolled strips on the basis of computer simulation of the rolling process in the DEFORM-2D program. It was determined that the size of alternating shadow zones on the surface of cold rolled strips received through simulation complies with experimental data. The comparison of the strip surface profile change depending on work roll vibration frequency and rolling speed demonstrated that rolling speed increase leads to increase in width of transversal stripes, and increase of vibration frequency leads to their decrease. The results of computer simulation led to the conclusion that vertical vibration of work rolls as the oscillation curve according to the Harmonic Law does not significantly influence the longitudinal strip off gauge. It was found that work rolls horizontal vibration does not influence the nature of deviations in the strip surface profile. Recommendations on use of simulation results are provided to evaluate the strip surface profile
Transforming educational space under the impact of the pandemic: student and teacher well-being in higher education
The article presents the study of some areas of educational space transformation under the COVID-19 pandemic influence. The focus of attention is on such problems as the cognitive well-being of the student, the tutor model of teacherstudent relations in the digitalising educational space, the functioning of academic mobility institution in a pandemic and post-pandemic world. Cognitive well-being of students implies mastering digital literacy with strict adherence to the norms of digital ethics. A tutor in modern education plays the role of not only a developer of an individual educational trajectory, but also a controller and educator. For the successful implementation of tutoring functions, the teaching staff of universities needs additional training. The main trends in academic mobility are internal and virtual mobility. The authors conclude that educational organisations need for adequate infrastructural policy, and educational space – inevitable transformations in budget financing. The results of the article can be used in further research on the higher education transformation problems, in the development of proposals and recommendations for specialists in the of higher education management field for use in practice
Activity cycles of late-type stars
Рассмотрены методы и результаты исследования холодных пятен, хромосферных неоднородностей, вспышечной активности и их долговременных изменений у звезд поздних спектральных классов.We considered methods and results of the observations of long-term variations of stellar spots, chromospheric inhomogeneities, and flare activity on late-type stars.Работа А. В. Кожевниковой выполнена при финансовой поддержке государства в лице Министерства образования и науки Российской Федерации (базовая часть госзадания, РК № АААА-А17-117030310283-7), а также Правительства Российской Федерации (постановление № 211, контракт №02.A03.21.0006).Работа И. Ю. Алексеева выполнена в рамках плановой темы ФГБУН КрАО РАН «Магнитные поля и эволюция магнитной активности звезд».Работа О. В. Козловой и И. Ю. Алексеева частично выполнена в рамках проекта «Активность звезд поздних спектральных классов на разных стадиях эволюции» (грант РФФИ 16-02-00689)
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