Heat transfer and critical heat flux on flat rectangular (16´24 mm) heat-releasing surfaces (HS) made of aluminum alloy D16 and modified by microarc oxidation (MAO) were investigated. Two types of coatings made using different electrolytes were studied: KOH and phosphates. Coatings had good adhesion to the HS and high dielectric strength. The thickness of coatings was 20 and 7 µm, respectively. The studies were carried out using freon R21 under conditions of natural convection with horizontal orientation of the HS. For comparison, measurements were carried out on identical working sections without a modifying coating: the first section was polished; the second one was ground with a roughness of 20 μm. It was shown that the heat transfer intensity on the modified HS was not lower than on the HS polished with a roughness of 20 μm, and it was almost twice as high as that on the polished HS. The values of the critical heat flux on the studied surfaces were almost the same. The use of these types of coating provides electrical insulation of the heat-releasing element without compromising the efficiency of heat removal.
The paper presents the calculated spectral densities of radiation energy fluxes and the emissivity factors of combustion products from model liquid and solid propellant rocket engines for the conditions of the combustion chamber, nozzle, initial and main sections of the plume. The influence of temperature non-equilibrium between gas and particle flows on the spectral and integral emission characteristics of combustion products is investigated. The calculated results of this work are compared with experimental and computed data of other authors. Particular attention is focused on the nature and level of emission at different locations of outflowing combustion products. The results of the work may be used to choose a section of the spectrum when determining the temperature of combustion products by pyrometric methods.
A.A. Morozov
Kutateladze Institute of Thermophysics SB RAS, Novosibirsk, Russia
Keywords: gas expansion dynamics, pulsed laser ablation, direct Monte Carlo statistical simulation, Gaussian beam, flat-top beam
In laser ablation, the nonuniform distribution of energy across the laser beam leads to a nonuniform heating and evaporation of the material from the irradiated surface. The influence of nonuniform temperature and that of the nonuniform flux of evaporated material from the surface on the laser-plume expansion dynamics during the nanosecond laser ablation in vacuum were studied. It was assumed that the surface temperature depended linearly on the laser radiation energy. Direct Monte Carlo simulation of pulsed gas expansion for a flat-top laser beam and for a Gaussian beam has been carried out under the assumption of no absorption of laser radiation in the plume. For the flat-top beam, the surface temperature proved to be areally uniform over the entire irradiation spot, whereas for the Gaussian beam, the temperature varied along the spot radius. It is shown that for both beams, the final distributions of particles in the plume are almost identical. However, in the case of the Gaussian beam the plume moves a little faster in comparison with the flat-top beam, which circumstance leads to an increased kinetic energy of particles passing through the time-of-flight detector by 2-4 %.
M.A. Vasyutin, E.V. Danilova, N.D. Kuzmichev
Ogarev Mordovia State University, Saransk, Russia
Keywords: heat transfer, inhomogeneous heat equation, boundary value problem, beryllium copper, NbN film
The process of heat transfer in NbN film while applying a pulse of current is considered using the 2D inhomogeneous heat equation. The boundary value problem is solved for a longitudinal cross-section in the film; the heat transfer problem is solved for a system “contacts-film-substrate-thermostat”. The temperature evolution for the film cross-section since the pulse start till the temperature relaxation is visualized. The maximum film heating is evaluated. It was shown that the contact material (beryllium cooper BeCu) ensures the effective heat drainage from a superconductive film existing in the resistance mode while passing a high density current through the film. The developed simulation method and the material for the contacts can be used for other types of metallic or semiconductor films.
Analytical formulas are derived for describing the direct pyrolysis of methane in a bubble column loaded with a catalyst molt. This math can be implemented in research or commercial computer codes aimed to multiparametric optimization of the metal bath (with consideration of its cost and catalytic performance), setup dimensions and productivity. These analytical expressions can be used also for validation of numerical codes.
On May 27, 2022, Academician of the Russian Academy of Sciences Dmitry M. Markovich, a well-known scientist, scientific administrator, Director of the Institute of Thermophysics SB RAS, Chief Academic Secretary of the SB RAS, member of the Presidium of the Russian Academy of Sciences, celebrated his 60th anniversary.
On May 2, 2022, Professor Valerian I. Yakovlev, a prominent specialist in the field of fluid, gas and plasma mechanics, Doctor of Physical and Mathematical Sciences, member of the editorial board of the journal "Thermophysics and Aeromechanics" turned 90 years old.
S. V. Solovieva
Samara State Transport University, Samara, Russia
Keywords: criticism, critical thinking, educational standard, competence-based approach, soft skills, engineering training, profession, dilettantism
Introduction. The implemented competency-based approach raises many questions, including: what skills should be included in the portfolio of basic literacy in the 21st century? Regardless of one position or another, critical thinking is one of the universal competencies in higher education. The purpose of the study is the explication and comparison of the concepts of critical thinking proposed by philosophers, experts and practitioners of educational activities. Methodology. The object of research is the concept of critical thinking in engineering education. The subject of the study is the place and meaning of critical thinking in the standards of higher education in Russia (considered on the material of the Transport University). A critical, constructivist and competence-based approach is used as a priority methodology. Discussion. In the FSES HE 3++, the list of universal competencies includes the position of the formation of “critical thinking” (UK-1). This competence should be formed in all students of the transport university. The conflict between experts (teachers, managers, philosophers) is associated with a different understanding of the content of competence, its place in the educational program and its impact on professionalism. It substantiates the idea that a sharp reduction in the volume and range of courses in the soft skills segment, misinterpretation of the concept and methodology of critical thinking by managers (who rely on strict adherence to the standard), leads to an increase in dilettantism in teaching, demonstrates the gap between philosophical scientific research and the practice of teaching philosophy in a transport university. Conclusion. The practice of developing critical thinking among engineering students reveals a contradiction between understanding the profession as a system of qualification requirements (where critical thinking does not matter) and the model of the profession as a dynamic portfolio of competencies (where it is impossible to build a successful career trajectory without it).
A. K. Erokhin1,2
a:2:{s:4:"TEXT";s:158:"1University of the Prosecutor’s Office of the Russian Federation, Vladivostok, Russia 2Far Eastern Law Institute, Vladivostok, Russia";s:4:"TYPE";s:4:"html";}
Keywords: philosophy of education, Karl Popper’s theory of falsification, objective paradigm of education, subjectively oriented paradigm, traditional teaching, practice-oriented learning, critical thinking, practical pedagogy, social engineering, cybernetic didactics
Introduction. Practice-oriented learning is actively being introduced into modern education at any level. Its philosophical foundations were laid by critical rationalism, which had a huge impact to many areas of education and science. The purpose of the article is to determine the basic foundations of the critical-rationalist philosophy of education, as well as to find out its new meanings and values for society. Methodology. Conceptual-semantic and comparative analysis are used in the article as the main research methods. The Karl Popper epistemology is taken as a starting point for researching the theoretical foundations of the practice-oriented learning model and its influence to the formation of critical rationalism is considered. The conceptual-semantic and comparative analysis of the critical rationalism concepts is used. Discussion. Attention is drawn to two main educational paradigms: “cognitive” - aimed to obtaining knowledge and subjectively oriented - aimed to the development of the subject as a person or his personal characteristics with the help of new learning technologies. The objects of critical analysis are the empirical paradigm, the falsified approach to pedagogical research, the complex relationship between pedagogical theory and practice, as well as the problem of value neutrality in pedagogical science. The results obtained allow us to present the debatable, but apparently inevitable role of the teacher in the educational process as a subject that encourages a student or schoolchild not so much to gain knowledge as to acquire useful self-learning skills. Conclusion. The conclusion is made about the positive contribution of critical rationalism to the professionalization of teachers and students. The results obtained have methodological significance associated with understanding the place and role of intelligent technologies in the implementation of the educational process at any level. They can also be used in further practical and theoretical studies of higher education.
L. V. Khokhlova
Nizhny Tagil State Socio-Pedagogical Institute RSPPU, Tagil, Russia
Keywords: assessment, self-assessment, reflection, dialogue, critical thinking, dialogue, problem-based learning, critical analysis
Introduction. The problem of assessing the knowledge of university students is relevant due to the emergence of new technologies and learning formats. The formal assessment of knowledge according to exam standards is being replaced by the individualization of the process of assessing not only knowledge, but also the level of competence of the student. It is important to investigate the critical thinking of students in its intention to evaluate knowledge. Methodology. The research methodology is based on a systematic understanding of critical thinking. The qualities of critical thinking in the process of knowledge assessment are analyzed. Based on the synthesis of interactions of thinking qualities, assessment methods, the specifics of philosophy teaching technologies and the possibilities of philosophical reflection, the importance of self-assessment is substantiated. The structural approach allows us to consider self-assessment as an independent construct functioning outside the evaluation procedure, but dependent on this procedure and participating in it. Discussion. The discussion is based on the use of their own model of critical thinking. The components of critical thinking are discussed. The interaction of the critical component with the qualities of reflexivity, constructiveness of critical thinking is considered. The analysis of students’ evaluation activity in the context of critical thinking allows us to determine the special place of philosophy as an academic discipline that forms critical thinking. Due to the dialogic nature of the content of the discipline, the use of dialogue technologies becomes possible. The idea is put forward that evaluation is most productive if it is a process of building dialogues between a teacher and a student, a student and other participants in a group dialogue. The role of self-assessment and the possibilities of its development in the process of knowledge assessment are analyzed. The most productive result is the coincidence of assessment and self-assessment in the course of philosophizing. Conclusion. Assessment methods should be aimed at the formation of the student’s openness, readiness to discuss the results of activities and the development of adequate self-assessment. These possibilities are realized through the constructive nature of philosophical criticism. Technologies for the development of critical thinking in the study of philosophy can be used in the process of evaluating knowledge. The technology of problem-based learning, dialogue technology, philosophical analysis with the use of rating, forming the qualities of critical thinking, have an impact on the student’s self-esteem.
