bluuebunny/crossref_metadata_2025 huggingface dataset:
Helping Students to Build Multicultural and Multidisciplinary Competences: A Pilot of Challenge-Based Collaborative Learning on a Digital Gamified Platform
Authors: Lau Martin , Chan Isaac , Wong Eva Y. W. , Kwong Theresa , Gibson David
Published: August 2019

Global issues such as poverty, hunger, and environmental problems are inextricable and cannot be solved comprehensively by homogeneous groups. With the advance of technology, collaborations with peoples at different geographical locations can be achieved effectively. Higher education in the 21st Century must therefore facilitate students to learn how to eclectically connect their creativity and problem-solving skills with technology, and most importantly to work with heterogeneous groups to solve complex global issues.This paper will elaborate on a pilot study of a project in Hong Kong, titled the CCGame Project, which aims to heighten students’ multicultural and multidisciplinary competences by deploying gamified learning and challenge-based learning. Team-based, self-guided learning is the core of the challenge-based learning approach. To preserve students’ interest in learning and accomplishing the tasks for the team, cloud-based learning platforms have been deployed. In the pilot, the online learning platform collected data for analysis of individual and team behaviour. The pilot demonstrated that students could work in a diverse team to complete a challenge. Evidence-based results supported with data analytics will be presented and the project’s plan of work will also be elucidated in this paper.
Ataluren use in patients with nonsense mutation Duchenne muscular dystrophy: patient demographics and characteristics from the STRIDE Registry
Authors: Muntoni Francesco , Desguerre Isabelle , Guglieri Michela , Osorio Andrés Nascimento , Kirschner Janbernd , Tulinius Már , Buccella Filippo , Elfring Gary , Werner Christian , Schilling Traci , Trifillis Panayiota , Zhang Olivia , Delage Abdallah , Santos Claudio L , Mercuri Eugenio
Published: August 2019

Aim:
Strategic Targeting of Registries and International Database of Excellence (STRIDE) is an ongoing, multicenter registry providing real-world evidence regarding ataluren use in patients with nonsense mutation Duchenne muscular dystrophy (DMD) in clinical practice (NCT02369731). Here, we describe the initial demographic characteristics of the registry population.
Patients & methods:
Patients will be followed up from enrollment for ≥5 years or until study withdrawal.
Results & conclusion:
As of 9 July 2018, 213 DMD boys were enrolled from 11 countries. Mean (standard deviation) ages at first symptoms and at study treatment start were 2.7 (1.7) years and 9.8 (3.7) years, respectively. Corticosteroids were used by 190 patients (89.2%) before data cut-off. Mean (standard deviation) ataluren exposure was 639.0 (362.9) days. Six patients withdrew. STRIDE is the first drug registry for patients with DMD and represents the largest real-world registry of patients with nmDMD to date.
Property Tax Cap Policy in Indiana and Implications for Public School Funding Equity
Authors: Bowling Scott J. , Boyland Lori G. , Kirkeby Kim M.
Published: August 2019

The purpose of this research was to examine funding losses experienced by preschool to grade 12 (P–12) public school districts in Indiana, U.S., from an equity standpoint after the implementation of statewide property tax caps. All Indiana public school districts (N = 292) rely on property taxes as a major source of revenue, but districts experienced widely varying losses after the tax reform. Analyses across an array of district characteristics revealed significant relationships between differential funding losses and demographic indicators, including total student enrollment and the percentages of certain minoritized students. Implications for policy and practice include the integration of findings with essential research on funding equity in public education and attention on leadership toward reducing funding disparities.
Consumers' perceived usefulness of online reviews: Effects of emotional certainty and product involvement
Authors: Li Yujie
Published: August 2019

In this study I examined 2 products for the effects of the level of consumers' involvement on their perception of the usefulness of online reviews from the perspective of emotional certainty. I used the experimental method of scene simulation verification with a sample comprising 727
participants. Results show that for both low- and high-involvement products, a review in which a positive emotion that is certain (happiness) is expressed is perceived as more useful than one expressed with an uncertain positive emotion (hope); for low-involvement products, the reviews in
which a negative emotion that is certain is expressed (anger) are perceived as more useful than those with an uncertain negative emotion (worry); when emotions expressed in the reviews are the same but level of involvement with the products differs, compared with high-involvement products,
consumers perceive online reviews of low-involvement products as being more useful. This study enriches the research on the content structure of online reviews and provides a reference platform to optimize the evaluation system.
Investigation of corrosion damage of wrought aluminium alloys at full-scale accelerated tests. Part 2. Pitting corrosion
Authors: Kurs M. , Goncharov A.
Published: August 2019

The paper presents the results of a study of pitting corrosion of aluminum alloys of seven doping systems after testing by the full-scale accelerated method. The advantages of the method of laser scanning microscopy in the analysis of pitting corrosion are shown, which makes it possible to improve significantly the accuracy of measurements in comparison with the metallographic method. Peculiarities of the kinetics of pitting growth under long-term, accelerated tests were studied, the role of pitting corrosion in the part of characterizing the alloy’s susceptibility to local corrosion failure was shown.
The effect of microalloying on mechanical properties of low-carbon chromium-nickel-molybdenum steel
Authors: Golosienko S. A. , Minyakin N. A. , Ryabov V. V. , Semicheva T. G. , Khlusova E. I.
Published: August 2019

The work covers the effect of niobium, as well as niobium and vanadium together, on mechanical properties of high-strength chromium-nickel-molybdenum steel after thermal improvement (heat treatment). The mechanical properties of steels are determined after applying various tempering temperatures (from 580 to 660°C), durations of tempering (from 1 to 16 hours), and also after quenching from rolling heat and furnace heat with subsequent tempering. It is shown that after quenching and tempering in the temperature range 580– 660°C, simultaneous microalloying by niobium and vanadium, compared to microalloying by niobium alone, increases the yield strength but in significantly decreases toughness and ductility. Quenching from rolling heat increases strength while maintaining high toughness and the increase in strength is most noticeable for steel microalloyed only by niobium.
Interaction of tungsten in dry sliding against steel under high density electric current
Authors: Aleutdinova M. I. , Fadin V. V. , Mironov Yu. P.
Published: August 2019

The possibility of creating a wear-resistant dry sliding electrical contact tungsten/steel was studied. It was shown that tungsten caused severe wear of the quenched steel counterbody due to unlimited plastic flow of its surface layer at a current density up to 150 A/cm2 . This indicated the impossibility of achieving satisfactory characteristics of such a contact. Low electrical conductivity and wear resistance of the contact tungsten/steel were presented in comparison with the known high copper/steel contact characteristics under the same conditions. X-ray phase analysis data of the steel sliding surfaces made it possible to state that the cause of the unsatisfactory sliding of tungsten was the absence of the necessary concentration of FeO oxide on the sliding surface of the steel.
Biotechnological method of obtaining nanoparticles of silver, cadmium and zinc sulfides. Physico-chemical characteristics. Creation of polymeric nanocomposites
Authors: Zhuravliova O. A. , Voeikova T. A. , Bulushova N. V. , Veiko V. P. , Ismagulova T. T. , Lupanova T. N. , Lobastov S. L. , Retivov V. M. , Debabov V. G.
Published: August 2019

A simple and environmentally safe method for obtaining stable nanoparticles of metal sulfides nanoparticles – NpAg2S, NpCdS and NpZnS was developed using different strains of microorganisms in an aqueous solution of metal salts and sulfur sources at the Research Center "Kurchatov Institute" – GosNIIgenetika. The concentration of nanoparticles is 1–4 mg/ml in aqueous suspensions. Using of the methods of electron microscopy, spectrofluorimetry, dynamic light scattering determined the main characteristics of biogenic nanoparticles: shape, size distribution, crystal structure, effective diameter, luminescent spectrum, zeta potential. According to its characteristics, these nanoparticles are referred to quantum dots. It is established that the stability of nanoparticles in aqueous suspensions is due to protein molecules adsorbed on the surface of nanoparticles, which are supplied by cells of microorganisms. Effective immobilization of biogenic nanoparticles on the surface of various polymer supports has been carried out. Biogenic nanoparticles along with nanoparticles obtained by physico-chemical methods can be used as fluorophores for imaging of biological processes, also as photocatalysts, solar cells and for new nanocomposite materials.
Experimental study of vibroinsulating properties of modern structural polyurethane
Authors: Yakovlev S. N. , Chernysh A. A.
Published: August 2019

Modern mechanical engineering often uses polyurethane elastomers as vibroinsulating material. It is difficult to choose the most perfect structural polyurethane among a large number of proposed materials for manufacturing shock absorbers. The article presents experimental research of vibroinsulating properties using two parameters out of five. Based on preliminary tests, an implicit preference is given to one of the three proposed materials. The energy absorption coefficient and the creep of the elastomer are chosen as criteria for evaluating the vibroinsulation properties of polyurethane elastomers. Final choice of polyurethane elastomer for shock absorbers manufacturing could be made if additional tests are carried out for studying three criteria.
Studying changes in the electrical resistance of carbon-nanotubes-modified elastomers during their compression, stretching and torsion
Authors: Yagubov V. S. , Shchegolkov A. V. , Shchegolkov A. V. , Memetov N. R.
Published: August 2019

Developing "smart" materials with improved both structural and functional characteristics is one of the promising areas of materials science. Measuring the electrical resistance of CNTs-modified (various mass contents) polymers and in particular, elastomers during performing several tests (compression, stretching, and torsion) at a constant current is relevant in electrical engineering, mechanical engineering, aviation, and space industry. Changes in the elastomer shape under different types of testing lead to the destruction of macromolecules and the structuring of the material as a whole. Therefore, it is important to study the effect of CNTsbased modifying fillers on the elastomer. When compressing, stretching or twisting the nano-modified elastomer, along with the mutual movement of its macromolecular fragments and aggregates, the modifier particles also move, which generally determines the transport of electrons in the resulting structure and affects the physical and mechanical parameters of the composite material. To conduct studies, elastomers containing different amounts of a CNTs-based modifying filler were prepared. To investigate and elucidate relevant dependencies, a measuring system (MS) was constructed, which makes it possible to determine electrical resistance values of the composite material with different CNTs contents in the polymer matrix composition exposed to various mechanical loads. Basing the research results, it was established that the electrical resistance of the elastomer composites modified with 1.0–2.5 wt.% CNTs decreases when compressing from 0 to 100 N, whereas when the compression force ranges from 100 to 350 N, the electrical resistance remains unchanged. When the elastomer composites modified with 2–2.5 wt.% CNTs were stretched by 30–40 %, the electrical resistance was found to increase from 5·103 to 1.9·107 Ω.
Theoretical and experimental studies of composite materials reinforced by carbon fabrics. Part 4: Mechanical and analytical model of structure deformation of the carbon fabric
Authors: Primachenko B. M. , Strokin K. O.
Published: August 2019

Theoretical studies of the deformation of the carbon fabric structure have been performed. The paper describes investigations that made it possible to obtain functional relationships between the mechanical characteristics of the fabric and the parameters of the structure of carbon fibers, their mechanical characteristics, the parameters of the structure and the technological parameters of the fabric. Based on theoretical studies, mechanical and analytical models of structure deformation of carbon fabric were built.
Global trends in carbon fiber research
Authors: Amangeldiuly N. , Fedorov M. V.
Published: August 2019

The review provides an analysis of global trends in current research in the field of carbon fiber composite materials. The paper considers studies conducted in 2018 and identifies four priority areas by assessing the amount of their funding. The mentioned areas include the utilization of carbon composites, optimization of their production process, the use of carbon composites in the aviation and shipbuilding industries. The review may contribute to the determination of high-priority and relevant research that will be conducted in the near future.
Research of recrystallization processes in lowcarbon low-alloyed steel during high-temperature rolling modeling
Authors: Korotovskaya S. V. , Sych O. V. , Khlusova E. I. , Yashina E. A.
Published: August 2019

Processes of dynamic and static recrystallization occurring at different conditions of plastic deformation (reduction modes, deformation temperature) of low-carbon low-alloyed steel are under consideration. Modeling of thermomechanical processing is carried out at Gleeble 3800, followed by complex microstructural analysis. Temperature-deformation conditions leading to formation of uniform dispersed structure are revealed during the investigations. In conclusion the results of implementation in industry of worked out hot rollingmodes are given.
Model of corrosion cracking of irradiated austenitic steels. Part 1. Analysis of damage mechanisms and formulation of the defining
Authors: Margolin B. Z. , Sorokin A. A. , Pirogova N. E. , Potapova V. A. , Toivonen Aki , Sefta Faiza , Pokor Cédric
Published: August 2019

Mechanisms having a potential effect on irradiation assisted stress corrosion cracking (IASCC) of austenitic steels in the LWR environment have been analyzed. Based on the analysis and generalization of reference and original data on IASCC, an IASCC initiation criterion has been formulated. Conditions for grainboundary microcrack propagation by IASCC mechanism have been formulated. The nature of low-temperature creep of irradiated austenitic steels has been considered, constitutive equations have been derived. Relying on the formulated criterion of grain-boundary microcrack nucleation and the derived creep equations, an IASCC initiation model has been developed. The model allows one to predict the dependence of the threshold stress σIASCC th on neutron dose and also to calculate the IASCC initiation time with stresses exceeding σIASCCth .
Electron-beam welding of large thickness steels of oil producing platform components
Authors: Aleksandrov N. V. , Blank E. D. , Eroshkin S. B. , Sharapov M. G.
Published: August 2019

The paper treats problems of reducing the cost of welding and improving the quality and productivity of welding parts of cold-resistant steel of great thickness during the construction of oil platforms. The design of tooling structure, and devices for electron-beam welding have been developed such as welding wire feeder, video observation system, software for controlling the workpiece moving and the electron beam gun travel.
Viability of turbine blade material with a long service life
Authors: Berdnik O. B. , Tsareva I. N. , Chegurov M. K.
Published: August 2019

This article deals with structural features and characteristic changes that affect the mechanical characteristics after different service life in real conditions using the example of the blades of the 4th stage of turbine GTE-45-3 with an operating time of 13,000 to 100,000 hours. To study the change in the state of the material under different operating conditions, determine the degree of influence of heat treatment on the regeneration of the microstructure, and restore the mechanical characteristics of the alloy after different periods of operation, non-standard methods were used: relaxation tests on miniature samples to determine the physical yield strength and microplasticity limit and quantitative evaluation of the plasticity coefficient of the material from experimental values of hardness, which allow us to identify the changes occurring in the microvolumes of the material and predict the performance of the product as a whole.
Researching structure heterogeneity of VT41 titanium alloy billet after thermomechanical treatment
Authors: Medvedev P. N. , Naprienko S. A. , Kashapov O. S. , Shpagin A. S. , Popov I. P.
Published: August 2019

The heterogeneity of the titanium VT41 structural state after hot upset test was investigated by analytical methods of optical and scanning microscopy. Vickers microhardness measurements were performed to estimate the mechanical properties. The analysis of the distribution of deformation and the features of the formation of the structural components of the specimen. Globular grains were deformed by the mechanism of intergranular slipping. β-grains and α-plates made the greatest contribution to plastic deformation. Lamellar grains of α-phase in the zone of localization of deformation undergo recrystallization. The dimensions of the zone in which the recrystallization occurred, coincide with the zone of localization of the deformation, estimated by macrostructure. When tempering the billet, the β-phase in the center of the sample breaks down into α-plates, and in the near-surface areas into smaller grains, probably representing needle-like β-titanium martensite. A decrease in microhardness in the central regions may be due both to recrystallization and to the fact that martensite has been quenched in the surface layers.
Application of cobalt-based alloys of Co–Cr–Si–B system for protective coatings
Authors: Belyakov A. N. , Bystrov R. Yu. , Gerashchenkov D. A. , Vasilyev A. F. , Bobkova T. I. , Makarov A. M. , Prudnikov I. S. , Farmakovsky B. V.
Published: August 2019

The paper studies an alloy of Co–Cr–Si–B system for obtaining powder materials and functional coatings based on it. It is shown that nanocrystalline precipitates are formed and increase substantially the microhardness of the coating when rare-earth elements, namely yttrium, lanthanum, and cerium, are introduced into the alloy.
Analysis of the stress-strain state of copper M0B under different schemes of equal channel angular pressing and its effect on the structure and physical and mechanical properties
Authors: Sennikova L. F. , Volkova G. K. , Tkachenko V. M.
Published: August 2019

The results of studies of the stress-strain state of copper M0b after deformation under different schemes of equal channel angular pressing (ECAP) are presented. The level of macro and micro stresses in copper has been determined in various ECAP modes. It is shown that the strength properties, deformation porosity and parameters of the fine copper structure differ depending on the loading pattern.
Structure and current melting densities of microwires in glass insulation made of copper and resistive alloy based on nickel
Authors: Farmakovsky B. V.
Published: August 2019

The paper studies the structure of cast microwires in glass insulation, obtained at the current density, which leads to melting of the metal core. High melting currents values allow us to recommend cast microwires as low-base fuses against current overloads in electric circuits.
Composite cladded powders for spraying of protective coatings
Authors: Gerashchenkova E. Yu. , Bobkova T. I. , Samodelkin E. A. , Farmakovsky B. V.
Published: August 2019

The paper presents results of the development of technology for producing cladded and surfacealloyed powder materials. High-speed mechanosynthesis of matrix powders of FeCrAl and solid nanosized particles of tungsten carbide occurs in a disintegrator in the presence of an active gas phase (nitrogen).
Nanostructured powders based on aluminum reinforced by silicon nitride designed for spraying of multifunctional strengthened coatings
Authors: Bobkova T. I. , Farmakovsky B. V. , Sokolova N. A.
Published: August 2019

The work deals with topical issues such as development of composite nanostructured powder materials. The results of creating powders based on the system “aluminum–nitride of silicon” are presented. Complex investigations of the composition, structure and properties of powder materials, as well as coatings formed on their basis by supersonic cold gas dynamic spraying, were carried out. It has been found that the high-energy treatment of a powder mixture of aluminum with nanofibers of silicon nitride provides the formation of a composite powder in which a new phase of the Si(1-х)AlхO(1-х)Nх type is formed, which additionally increases the hardness in the coatings to be sprayed.
Functional gradient coatings obtained by supersonic cold gas dynamic spraying
Authors: Bobkova T. I. , Vasiliev A. F. , Prudnikov I. S. , Farmakovsky B. V.
Published: August 2019

The paper studies the development of a technology for obtaining a wear-resistant functional gradient coating during supersonic cold gas dynamic spraying. The process goes due to the variation of the composition of the gas phase in a heterophase flow. The coating has a high microhardness (up to 12 GPa) on the peripheral layers and wear resistance is 3 times higher than that of coatings obtained by traditional technology.
Powdered composites of Al–Zn–Sn alloys for functional coatings
Authors: Bobkova T. I. , Beliakov A. N. , Gerashchenkov D. A. , Gerashchenkova E. Yu. , Vasiliev A. F. , Farmakovsky B. V.
Published: August 2019

The features of the process of obtaining a powder composition from an alloy based on the Al–Zn– Sn system are studied. A technology has been developed for obtaining powders of optimal composition, including Al; 6–11% Zn; 6–11% Sn; 2–4% Si; 0.6–0.8% Ce. Functional wear-resistant coatings recommended for practical use in products of precision and power engineering were made by supersonic cold gas dynamic spraying.
Research and development of technology for laser configuration of sensitive element of fluxgate inclinometer
Authors: Yulmetova O. S. , Poslyanova O. N. , Shcherbak A. G. , Zhukov M. V.
Published: August 2019

The paper presents the results of thermodynamic analysis of oxidation processes occurring during laser treatment of amorphous magnetically sensitive ribbon (71KNSR) in air and in the atmosphere of argon. Kinetic assessment of the rate of chemical reactions is based on the Arrhenius equation. The results of analytical calculations show that the decrease of magnetic properties of the alloy after laser treatment in the air is mostly determined by the formation of iron oxides Fe2O3 and Fe2O4. Chemical elemental analysis of the composition of the samples after laser configuration in argon shows a significant decrease in their composition of oxygen compared to samples configured in the air. Analysis of samples using scanning electron and magnetic force microscopy confirms the preservation of the magnetic properties after treatment in argon. The developed technology is used for the manufacture of a sensitive element of a fluxgate inclinometer.
Evolution of the structure and phase state of the heat-resistant intermetallic coating of operating turbine blades
Authors: Tsareva I. N. , Berdnik O. B. , Maksimov M. V. , Razov E. N.
Published: August 2019

The paper treats important problems of domestic engineering, namely, the urgent necessity to increase service life of large-sized turbine blades of the power gas-turbine stations operated on thermal power plants. The heat-resistant coating of the Ni–Co–Cr–Al–Y system with intermetallic phase structure β-(Ni, Me)Al + γ′-(Ni, Me)3Al has been developed. It was made by high-energy plasma powder spraying and intended for protection of blade surface against high-temperature and erosive gas flow. The article studies microstructure, phase structure and physicomechanical properties of a coating given in an initial state, and after laboratory research of heat resistance and a post-operational state at ~29 000 hours (time of real operation of the gas-turbine engine of the GTE-45-3 power station on thermal power plant). After long-term operation, a decrease in the content of the intermetallic phase of β-(Ni, Ме)Al in the phase composition, an increase in the pore size and a decrease in the hardness of the coating have been established. At the same time, erosion resistance and heat-resistant properties of the coating remain, and, consequently, there is a sufficient resource.
Studying the influence of ageing on the stress corrosion cracking initiation of low-carbon steels
Authors: Butusova E. N. , Mishakin V. V.
Published: August 2019

The paper presents results of a study of the stress corrosion cracking (SCC) processes of lowcarbon low-alloyed steels with different levels of ageing. It is shown that the limit of macroelasticity and the incubation period of the SCC decrease with the increase of the ageing level. This can be explained as follows: the limit of macroelasticity determines the beginning of microplastic flow in the material, actively affecting the process of stress corrosion cracking. Basing on selected test pattern the dependence of the stress corrosion cracking from the ageing level has a three-stage character. Behavior of the chosen characteristic is explained on the grounds of the theory of defects.
Effects of strain aging on fracture of low-alloy steels with different structure
Authors: Yakovleva E. A. , Motovilina G. D. , Khlusova E. I.
Published: August 2019

Low-alloy shipbuilding and pipeline steels are commonly subjected to thermomechanical treatment in order to form a ferrite-pearlite or ferrite-bainite structure. At the same time, a high density of lattice defect appearing in this treatment results in some structural instability fraught with the following aging in the production cycle or during the storage and exploitation. The present paper considers effects of the strain aging on steel fracture mechanism as well as efficient ways to reduce such effects.
Aqueous acid-aided corrosion products removal from the surface of the brass elements of heat exchangers
Authors: Mironovich L. M. , Eliseev A. Yu. , Eliseeva A. Yu.
Published: August 2019

The paper studies complex effect of various factors on the process of cleaning brass brand L-68, used for the manufacture of heat exchange equipment. It has been established that acids of various strengths can be used as working solutions. The speed of the cleaning process depends on the nature of the acid and its initial concentration. For strong acids, a working solution with low concentration is recommended, followed by an increase in their concentration during the cleaning process. Additional input of oxygen into the system and an increase of the working solution temperature increase the cleaning rate of brass. The cleaning process proceeds without significant changes in the surface configuration, and, consequently, the expenditure of metal.
On corrosion properties of ceramic materials for pump friction pairs in lead – bismuth environment
Authors: Stepanov V. V. , Kashtanov A. D. , Shchutsky S. U. , Agrinsky A. N. , Simonov N. I.
Published: August 2019

We consider the results of studies on the choice of material of the lower radial bearing of the pump, designed to circulate the coolant lead – bismuth. The circulation of the liquid coolant is provided by a vertical axial pump having a “long” shaft. In this design it is necessary to provide for the lower bearing the lubrication carried out with lead – bismuth coolant. Having analyzed the operating conditions of the axial pump, we decided to carry out the lower bearing in accordance with the scheme of a hydrodynamic sliding bearing. The materials of friction pairs in such a bearing must withstand the stresses arising from the operation of the pump, as well as the aggressive conditions of the coolant. Non-metallic materials – ceramics and carbon-based composite materials – were selected basing on the study of literature data for experimental research on the corrosion and heat resistance in the lead-bismuth environment.
Evaluation of crack resistance of 38KhN3MFA-Sh structural steel by fracture properties and elastic wave velocities
Authors: Evstifeeva V. V. , Litovchenko V. N. , Mishakin V. V. , Vorobyev R. A.
Published: August 2019

The results of the study on the effects of tempering temperature on 38KhN3MFA-Sh steel static strength and crack resistance are given. The fractured surface texture has been studied after various heat treatment modes using electron-fractography analysis. Relationships between the fracture properties and the critical stress intensity factor have been established. The effect of tempering temperature on the velocities of ultrasonic bulk waves has been investigated. A linear relationship has been found between the velocity of elastic waves and the critical stress intensity factor of 38KhN3MFA-Sh steel. The dependence discovered allows us to estimate the changes in crack resistance of steel using a non-destructive test method with variations in tempering temperature. The method of electron fractography has been used to analyze specimen fractures having a crack in structural high-quality 38KhN3MFA-Sh steel. Investigations of the fractured surface texture subjected to various heat treatment modes have shown that the microrelief is represented by flattened cone-shape pits. An increase in tempering temperature is accompanied by an increase in the diameter of flattened cone pits on the fractured surface. A quadratic dependence has been established between the crack resistance parameter and the diameter of the pits. It is shown that the contribution of ferrite matrix structural condition to crack resistance value is much more significant than the contribution of isolated carbides. The velocities of elastic waves in steel have been measured; their values increase with the growth of tempering temperature. The characteristics of strength and crack resistance of structural steel exposed to hightemperature tempering have been predicted based on the values of transverse wave velocities. Deviation of the predicted values of crack resistance K1С and ultimate strength σb from the experimental values does not exceed 5.4% and 12.6%, respectively.
Quality control of steel for large-sized welded structures of Arctic shelf. Application of Russian and foreign requirements
Authors: Filin V. Yu.
Published: August 2019

Future large-scale development of Arctic inevitably requires marine structures both of Russian and foreign manufacturers and, correspondingly, applying of domestic and foreign steels. So, it is expedient to compare Russian and foreign systems of standard requirements for steel products and welded joints’ metal applied at low temperatures. The paper analyzes their theoretical and experimental grounding as it is extremely important because the difference in requirements serves an instrument to drive out Russian steel manufacturers from international projects.
Model of corrosion cracking of irradiated austenitic steels. Part 2. Determination of model parameters and its verification
Authors: Margolin B. Z. , Sorokin A. A. , Pirogova N. E. , Potapova V. A. , Toivonen Aki , Sefta Faiza , Pokor Cédric
Published: August 2019

Based on the analysis and generalization of reference and original experimental data unknown coefficients, parameters and functions in constitutive equations of the model developed in the first part of article have been defined. The model has been verified. The model allows one to predict the dependence σIASCCth (below which SCC does not occur at any time of tests) on neutron dose and to calculate the time of SCC initiation at stresses higher than σIASCCth.
Methodical approach for studying kinetics of short and long fatigue cracks growth for irradiated reactor materials. Part 1. Statement of problem. The effect of the initial notch acuity on the fatigue crack rate on small-sized specimens
Authors: Smirnov V. I. , Minkin A. J. , Margolin B. Z. , Kokhonov V. I.
Published: August 2019

The paper considers methodical issues in the experimental research of fatigue crack growth kinetics when testing irradiated small-sized specimens. The effect of the initial notch acuity is studied on the long crack growth rate. The stress concentration zone sizes are estimated for notches of various types. A brif literature review of the main problems in the study of the growth kinetics of short fatigue cracks has been performed. The tasks of further research are formulated.
Research of quality of high-strength shipbuilding steel with high concentration of calcium
Authors: Miliuts V. G. , Tsukanov V. V. , Pavlov A. G. , Smirnova D. L.
Published: August 2019

The paper studies the microstructure, presence and qualitative composition of nonmetallic inclusions, mechanical tests of industrial smelting of high-strength shipbuilding steel with calcium concentration in the bucket sample of 0.009% have been performed. Steel with a high concentration of calcium is contaminated with a variety of stitch oxide inclusions, and therefore the mechanical properties of the rolled product are sharply reduced (impact strength, ductility in the Z-direction, fracture quality of technological samples). It is shown that the upper permissible limit of calcium content in steel is within the range 0.004–0.009%, but it is necessary to clarify it performing additional research. To ensure high purity of high-strength shipbuilding steel for non-metallic inclusions, it is vital to observe a strictly regulated technology of aluminum deoxidation and modification by ferrocalcium with obtaining the content of these elements in the metal in the previously recommended limits 0.01–0.02 and 0.002–0.004% respectively.
Carbon additives influence on mechanical properties of titanium near-alpha alloy
Authors: Kashapov O. S. , Pavlova T. V. , Kalashnikov V. S. , Popov I. P.
Published: August 2019

The article considers the influence of carbon in the range from 0.008 to 0.18 mass. % at the temperature of complete polymorphic transformation, microstructure and mechanical properties of near-alphatitanium alloy systems Ti–6.2Al–Sn–Zr–(2.19–3.53) Moeq–(0.18–0.28)Si–(0.008–0.18)С. Alloying with carbon is possible due to special titanium sponge or industrial ligatures. Six experimental forgings performed on bimodal microstructured ingots allowed to establish a rational level of carbon. It is shown that carbon alloying at solubility limit (up to 0.08% by weight) increases the heat resistance of the material, while a similar alloying with silicon gives a greater effect. The carbon effect on the strength at room temperature is negligible. Negative effect of carbon on the impact toughness of the alloys is marked. For the selected carbon alloying level at strength of 1165–1180 MPa, the impact viscosity remains at an acceptable level of KCU = 330–381 kJ/m2. The alloys of the investigated system allow hot deformation in heavy conditions under hammer forging at relatively low temperatures of the two-phase region.
Obtaining soft magnetic powder composites of the system ferromagnetic – diamagnetic
Authors: Korkina M. A. , Samodelkin E. A. , Farmakovsky B. V. , Vasilyeva O. V. , Kuznetsov P. A. , Gerashchenkovа E. Yu.
Published: August 2019

A method has been developed for producing a powder material of the ferromagnetic – diamagnetic system, intended for the manufacture of composite radar absorbing materials and coatings in the ultra-high frequency range. Composite powder material with a polymer diamagnetic matrix reinforced with a ferromagnetic nanocrystalline hardener is obtained by the method of ultrafast mechanosynthesis. The proposed technology of superfast mechanosynthesis allows to obtain a powder composition where each particle is a single mechanically connected system, while reducing the degree of amorphousness (no more than 80%) by maintaining the proportion of nanocrystalline precipitates in the amorphous matrix and, accordingly, increasing the magnetic permeability (up to 90 or more). The composite powder of the ferromagnetic – diamagnetic system thus obtained can be used to obtain radar absorbing materials with high shielding efficiency and a large absorption coefficient (at least 25 dB) in the frequency range from 1 MHz to 40 GHz.
Composite alloy based on Co–Cr–Si–Zr–TiB2–BN system for nanostructured powders and functional coatings
Authors: Skvortsova A. N. , Bobkova T. I. , Farmakovsky B. V. , Klimov V. N. , Dmitryuk A. I.
Published: August 2019

The paper studies the preparation of a composite nanostructured powder manufactured from an alloy of Co–Cr–Si–Zr–TiB2–BN system and describes functional coatings with high microhardness and corrosion resistance based on that powder.
Composite cobalt-based alloy for functional coatings deposition using heterophase transfer
Authors: Farmakovsky B. V. , Sokolova N. A. , Bobkova T. I.
Published: August 2019

The paper describes an alloy with a content of 20–26% Co, 17.4–21.1% Cr, 2.6–4.9% Si, 3–5% Re, 4–6% Zr, 0.2–0,6% Ce, 0.1–0.5% La, 0.3–0.7%Y, 2–4% Al. The cobalt-based alloy is applied as protective coating on components of precision engineering with adhesion 42–45 MPa, microhardness 3.6 GPa, corrosion resistance class 1, within the range of operating temperatures from –60 to 550°С.
Restoration and repair of equipment by supersonic cold gas-dynamic and micro-plasma spraying
Authors: Dmitryuk A. I. , Farmakovsky B. V. , Bobkova T. I. , Gerashchenkov D. A.
Published: August 2019

The technological process of restoring and repairing of equipment and its components by supersonic cold gas-dynamic and micro-plasma spraying has been developed. For steel products Fe–Cr–Al-based composite powder has been used being surface reinforced with tungsten carbide particles. For nickel and titaniumproducts composite powder from an alloy of the Ni–Cr–Mn–Sn–Si–W–Re system (Ce, La, Y) has been applied being superficially reinforced by corundum nanopowder. During the work, a high hardness of the applied coating, corrosion resistance and wear resistance were achieved. Real examples of the successful restoration and repair by powder materials are given, and spraying technologies are proposed.
Researching internal friction module of polyurethane elastomers under alternating bending with rotation
Authors: Podkolzina L. V. , Yakovlev S. N. , Chernysh A. A.
Published: August 2019

Today there is a large number of vibration-proof materials for the manufacture of shock absorbers in the market of structural materials. For a reasonable choice, it is necessary to perform comparative tests of different elastomers according to several criteria. The paper presents the results of two-parameters comparative tests of three brands of polyurethane elastomers. As the evaluation criteria, the internal friction module and the loss tangent of elastomeric materials under alternating bending with rotation are chosen. High stability of physicomechanical properties of polyurethane elastomers is studied in the entire frequency range of mechanical vibrations.
Thermal characteristics and physicomechanical properties of polyimidates
Authors: Mognonov D. M. , Ayurova O. Zh. , Ilyina O. V. , Kornopoltsev V. N. , Mangadaev A. M.
Published: August 2019

Polycondensation of equimolecular quantities of bis-imidoyl chlorides with bis-phenols in the environment of organic solvents synthesized imino-analogues of polyarylate – polyimidate. The received polymers are soluble in amide solvents, solvents of phenolic type and tetrachloroethane, and have significant interval between temperature of plastic deformation and thermal stability that presents a good possibility of their processing to products by modern industrial methods. The mechanical durability of the film materials of polyimidates is 65–90 MPa, obviously expressed dependence of the deformation-strength parameters on the value of the molecular weight of the polymer is observed. Despite the fact that polyimidates are of interest as intermediate polymer intermediates in the synthesis of polyaramides, they have their own complex of high thermal and deformation-strength characteristics, which makes them promising as adhesives, film materials, fibers and laminated plastics. One of the most important in practical terms properties of film materials based on polyimidates is their proton conductivity after doping in a solution of phosphoric acid, which allows the use of these polymers as membranes in the design of fuel cells of hydrogen energy.
Promising hybrid fabrics based on carbon and aramid fibers as a reinforcing filler for polymer composites
Authors: Zhelezina G. F. , Bova V. G. , Voinov S. I. , Kan A. Ch.
Published: August 2019

The paper considers possibilities of using a hybrid fabric made of high-modulus carbon yarn brand ZhGV and high-strength aramid yarns brand Rusar-NT for polymer composites reinforcement. The results of studies of the physical and mechanical characteristics of hybrid composite material and values of the implementation of the strength and elasticity carbon fibers and aramid module for composite material are presented.
Effect of oxidized technical carbon on surface energy of rubber
Authors: Nagornaya M. N. , Myshlyavtsev A. V. , Strizhak E. A.
Published: August 2019

The influence of carbon black N121 and N326, oxidized by active oxygen forms, in comparison with the influence of channel carbon black K 354 on the properties of rubbers based on butyl rubber was investigated. It was revealed that the introduction of oxidized carbon black samples into the composition of rubber compounds allows increasing the start time of rubber mixture scorching from 8.82 to 11.17 minutes, increasing the level of conventional tensile strength from 15, 52 to 16.68 MPa. It has been established that using rubber based on butyl rubber as a filler for carbon black N121 or N326, oxidized with 30% hydrogen peroxide, makes it possible to obtain rubber with a surface energy similar to rubber K 354.
AÇÃO DOCENTE: UM DIÁLOGO COM O CAMPO DA PESQUISA EM ENSINO DE CIÊNCIAS NO BRASIL
Authors: Da Fraga Goulart Andrea Oliveira , Vermelho Sônia Cristina Soares Dias
Published: August 2019

O presente artigo faz uma investigação sobre a ação docente, com base na produção científica do campo do ensino de ciências no Brasil nos últimos 16 anos. Tem como objetivo compreender o tema a partir das pesquisas na área de ensino. Para isso realizou-se uma detalhada revisão bibliográfica na plataforma da ANPED, no GT 08, voltado para a formação de professores, no Portal de Periódicos da CAPES e na Plataforma Scielo. Como resultado obtivemos um panorama que permitiu compreender como a área se posiciona acerca do tema e as dimensões que são abordadas na sua discussão. Nessa primeira abordagem, percebemos que a ciência o trata de formas variadas: enquanto processo, atitude, política; todas essas discussões de uma maneira ou de outra impactam no próprio processo formativo acadêmico do futuro docente. Contudo, não encontramos pesquisas que se voltassem para investigar qual concepção que os docentes possuem sobre o processo ensino-aprendizagem em si.
METODOLOGIA DE RESOLUÇÃO DE PROBLEMAS ARTICULADA À EXPERIMENTAÇÃO NO ENSINO DE CIÊNCIAS: UMA REVISÃO DE LITERATURA REALIZADA NO ENCONTRO NACIONAL DE ENSINO DE QUÍMICA
Authors: Goi Mara Elisângela Jappe , Borba Fabiane Inês Menezes de Oliveira
Published: August 2019

Neste trabalho apresenta-se uma revisão de literatura sobre o uso da metodologia de Resolução de Problemas articulada à experimentação. A amostra é constituída na análise dos artigos sobre as temáticas nos últimos três Encontros Nacionais de Ensino de Química (ENEQs) e foram encontrados 1563 artigos publicados no evento. A análise qualitativa dos trabalhos revelou que 13 artigos tratam da Resolução de Problemas articulada à experimentação no Ensino de Ciências e esses permitem levantar algumas características das experiências relatadas. As informações coletadas relacionam-se aos tipos de problemas articulado à experimentação, ao referencial teórico tratado nos documentos, aos tipos de metodologias utilizadas nas pesquisas e aos resultados produzidos a partir da articulação das estratégias metodológicas de Resolução de Problemas e Experimentação. Sinaliza-se que a revisão permitiu identificar vantagens do uso da metodologia de Resolução de Problemas articulada à experimentação. Essas duas estratégias metodológicas na perspectiva de investigação se mostram adequadas para o tratamento dos conteúdos de Ciências da Natureza.Resolução de problemas; Experimentação; Ensino de Ciências.
PRÁTICA PEDAGÓGICA NO ENSINO APRENDIZAGEM - PROBLEMATIZAÇÃO E LUDICIDADE
Authors: Souza Mauro da Cruz , Santos Marcello Silva e , Henriques Beatriz Amarante Araújo , Paula Rondinele Soares de , Gomes Aline Cristina Costa
Published: August 2019

Resumo  Muito tem sido discutido acerca de novas metodologias e tecnologias educacionais para fazer frente à rápida evolução da sociedade ocorrida nas últimas décadas. A popularização da informática e, principalmente, o advento da internet banda larga, torna a disponibilização de terabytes de informação uma tarefa simples, realizada em poucos minutos. Naturalmente, a qualidade desses dados, em termos de conhecimento aplicável, tende a ser constantemente questionada. Também muito se tem falado nas metodologias ativas, mas será que antes todas as metodologias tradicionais eram “passivas”? Será que professores na década de 1970 ou 1980 eram ineficientes por não disporem de modernas tecnologias educacionais? A pesquisa no Google seria tão infinitamente superior em relação à pesquisa na Barsa? Esses questionamentos iniciais são importantes para construir um entendimento preciso da evolução do processo de ensino-aprendizagem, separando o que é modismo das práticas efetivas de transmissão de conhecimento. Esse artigo apresenta um estudo de caso em que os alunos de uma turma de engenharia de produção são convidados pelo professor a romper os muros do campus e escolher um local inusitado para desenvolver uma ação prática em Ergonomia, disciplina do nono período, do ciclo profissional. O Bar do Lucio, é uma empresa familiar do ramo alimentício e de bebidas, próximo do campus de uma universidade em Nova Iguaçu, RJ. Ele excede sua dimensão jurídica ou econômica, sendo um símbolo que ainda permanecerá por décadas nos corações e mentes desses jovens estudantes de engenharia. As lembranças desses momentos “não acadêmicos” não se distinguirão daqueles em que todos buscavam o desvelamento de suas aptidões, a construção do saber formal e do autoconhecimento. O resultado mostrou que a interação do pesquisador-aluno com a fonte de seu aprendizado tende a potencializar a compreensão e assimilação do conteúdo tangível e pertencente ao “mundo real”.