bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of phase transition temperatures (melting, crystallization, rotator phases) of n-alkanes by the optical method
Authors: Kuryakov V N , Ivanova D D , Tkachenko A N , Sedenkov P N 
Published: May 2020

Abstract
The temperatures of phase transitions (melting, crystallization, rotator phases) were determined for a number of individual n-alkanes from C19H40 (n-nonadecane) to C28H58 (n-octacosane) by the optical method, a modified droplet technique. For this research, n-alkanes were presented as an emulsion in water without the addition of surfactants. Emulsions were prepared by ultrasonic dispersion of a small amount of n-alkane in water at a temperature above the melting point of the investigated n-alkane. The hydrodynamic radius of the dispersions measured by the dynamic light scattering (DLS) method was about 100 nm and did not change within a wide temperature range within the measurement accuracy. The temperatures of melting, crystallization, and rotator phase transitions of pure n-alkanes in the form of emulsion were determined from temperature-dependent measurements of the light scattering by the dispersions. The supercooling values for studied n-alkanes were also determined.
Effect of ions concentration in buffer solutions on the nucleation of hydroxyapatite surface on the octacalcium phosphate granules
Authors: Mikheeva P V , Yu Teterina A , Smirnov I V , Yu Fedotov A , Komlev V S 
Published: May 2020

Abstract
Octacalcium phosphate granules were subsequently immersed for different lengths of time from 1 day to 44 days at constant temperature 37±0.4°C in solutions, simulating the extracellular body fluids: Supersaturated Calcification Solution (SCS), Simulated Body Fluid (SBF), based on the ISO-10993 “Biological Evaluation of Medical Devices” standard. The role of buffer`s systems pH-value, time of the material exposure and calcium and phosphorus ionic concentrations were analysed with the main focus on kinetics of degradation, changes in the morphological characteristics and phase composition of octacalcium phosphate samples.
Reactive hot-pressed LaB6-W2B5 ceramics
Authors: Nesmelov D D , Novoselov E S , Titov D D , Ordan’yan S S , Perevislov S N 
Published: May 2020

Abstract
The heterophase LaB6-W2B5 composite with LaB6 content of 50 vol. % was fabricated by reactive hot pressing of the powder mixture of LaB6, W and amorphous boron at 1800 °C and 30 MPa for 15 min. The structure and phase composition of the synthesis products were analyzed by SEM, EDX and XRD methods. The effect of the pressure-induced anisotropic W2B5 grains growth was observed. The elastic modulus of composites investigated by resonance frequency method, and the Vickers hardness via indentation method.
Thermal conductivity of SiC-B4C materials obtained by reaction-sintering method
Authors: Perevislov S N , Motaylo E S , Novoselov E S , Nesmelov D D 
Published: May 2020

Abstract
In this research, temperature dependences of the thermal conductivity of reaction-bonded SiC – B4C composite materials at the temperature range of 293 – 1400 K were investigated. The effect of B4C concentration on thermal conductivity is shown. The thermal conductivity of SiC – B4C materials were compared with the thermal conductivity of materials based on silicon carbide and boron carbide obtained by different methods.
Advantages of drawing and rolling metals with pulse current
Authors: Troitsky O A , Stashenko V I 
Published: May 2020

Abstract
The results of studies on the drawing of copper and steel wires using pulsed current in the deformation zone are presented. The analysis of their structure and physicomechanical properties is given. As a result, the drawing forces of copper and steel wires are reduced by 30-35%, the electrical resistance is reduced by 18-20%, a more perfect axial texture appears, the ductility of the wires increases compared to warm drawing. In the steel wire, the α-phase content sharply decreases, which is predominantly released in the surface layer by several microns. We propose methods for the modernization of rolling equipment for technology using pulsed current. The efficiency of using a high-density pulsed current on a rolling mill for producing stainless steel from an initial billet of 2 mm thick and 100 mm wide 0.3 mm thick tape without intermediate annealing and oxide film is shown.
Novel materials for high-resolution three-dimensional printing using surface-selective laser sintering
Authors: Syachina M , Minaeva S , Krumins E , Howdle S , Popov V 
Published: May 2020

Abstract
A new approach for high-resolution three-dimensional printing using selective laser sintering is proposed. Novel ultrafine powder is synthesized and modified to face the requirements of the laser sintering process. The effect of the powder particle size and shape on the characteristics of the sintered structures is studied.
Reducing of holes effect on composite elements strength
Authors: Kh Akhmedshin E , Polilov A N , Tatus N A 
Published: May 2020

Abstract
Reducing the effect of holes on the attachment points of composite elements is one of the key tasks from the time the composites appeared to the present. Since the composite material and the structure are inseparable, it is necessary to design the joints at the stage of manufacturing the structural element. The work is devoted to the experimental assessment of the effect of holes made by various technologies on the strength of composite specimen. A significant increase in the bearing capacity of composite flat specimen, holes in which are made by the separation of the fibers during the manufacturing. For fiberglass, the bearing capacity of a specimen with a drilled hole decreased by 4 times, and the specimen with fibers “flowing around” the hole by only 25% compared to a solid flat specimen.
Phosphors based on Ce:(Pb,Gd)3(Al,Ga)5O12 epitaxial films: synthesis, optical properties, application
Authors: Vasil’ev D A , Spassky D A , Plotnichenko V G , Voronov V V , Khakhalin A V , Galstyan A M , Vasil’eva N V 
Published: May 2020

Abstract
Ce-doped (Pb, Gd)3(Al, Ga)5O12 single crystalline garnet films were grown using liquid-phase epitaxy method from supercooled PbO–B2O3-based melt solutions on substrates from Gd3Ga5O12 and Gd3Al2.26Ga2.74O12 single crystals. Optical absorption and photo- and cathodoluminescent properties of these epitaxial garnet films were studied. Ce-doped (Pb, Gd)3(Al, Ga)5O12 garnet films can be used as a fast phosphor in the design of a PIF-01 electron-optical converter.
Ceria-based solid solutions for environmental application
Authors: Zagaynov I V , Shelepin I V , Fedorov S V , Klimashin A A , Kulbakin I V 
Published: May 2020

Abstract
The work is focused on the investigation of the influence of metal oxide promoted ceria based materials with various dopants on the physicochemical, electrical and catalytic properties for CO oxidation in model reaction. The formation of stable solid solutions by doping gadolinium, bismuth, and third metal enhances the redox properties, oxygen vacancies, stability, and, of course, catalytic activity and electroconductivity.
Study of the processes of three-dimensional printing of caprolactone copolymers with methylphosphate groups
Authors: Mariyanats A O , Mironov A V , Nifant’ev I E , Shlyakhtin A V , Popov V K 
Published: May 2020

Abstract
Reconstruction of the damaged or missed organs or skeleton fragments is an ambitious target for regenerative medicine. Tissue engineering construction (TEC) comprising three-dimensional bioresorbable scaffold and living cells can become native tissue substitute. Scaffold should correspond to strict requirements. Generally, its physical-mechanical and biochemical characteristics should be comparable with tissue to be replaced. Besides, resorption rate of scaffold material should correlate with the tissue regeneration rate in each case. Thus, the effect of scaffold manufacturing methods on its properties is an important point in TEC design and fabrication. At present study, thermo-extrusion 3D printing of bioresorbable scaffolds based on polycaprolactone and its copolymer with polyethylene glycol and methylphosphate groups, synthesized by novel chemical route, was investigated. Scaffold surface morphology and its internal structures were studied by optical and scanning electron microscopy. The effect of thermal-induced degradation on polymers properties at various 3D printing processing parameters was analysed by gel-permeation chromatography, differential scanning calorimetry and mechanical testing. It was shown that optimizing experimental parameters the developed methods of thermo-extrusion 3D printing enable effective polymer scaffolds fabrication in accordance with their 3D computer model without significant changes of physicochemical properties of initial materials.
Screening of Process Parameters to Produce Xylanase from Aspergillus niger for Secondary Bioethanol Production
Authors: Tarrsini M , Ng Q H , Teoh Y P , Kunasundari B , Ang W U , Shuit S H , Ooi Z X , Hoo P Y 
Published: May 2020

Abstract
In recent years, the biotechnological use of xylanases has grown remarkably. Xylanase is a hydrolytic enzyme with a broad industrial application. In specific, xylanase can convert xylan into xylose, a fermentable sugar source for secondary bioethanol production. The objective on this study is to investigate the significance of different parameter effects for an efficient xylanase production from Aspergillus niger (A. niger). In this study, four factors: incubation temperature, medium pH, incubation time, and agitation speed were screened by performing One-factor-at-a-time (OFAT) analysis. Xylanase production with the maximal enzyme activity was successfully obtained from OFAT analysis under condition of 32°C, pH 5.0, 5 days, and 150 rpm.
Analysis of vibration response from high damping rubber bearing and lead rubber bearing for using in high rise building foundations subjected to earthquake
Authors: Alifani N , Nirbito W 
Published: May 2020

Abstract
Vibration due to earthquakes that occur in a high rise building like hospital building can disrupt the comfort, as well as operation of the hospital, and can cause casualties because usually, the building response to the earthquake is of a cantilever movement. The solution from a mechanical vibration point of view is to change the response of buildings to earthquakes so that hospital buildings are not destroyed by earthquakes by controlling the response of vibrations that produce lateral movement responses. One technology that is used to increase the resilience of buildings that subjected to earthquake, as well as control vibration response is the application of rubber bearing base isolation on the building foundations. High damping and lead rubber bearings base isolation are used on high rise building foundations which are designed to give lateral motion due to the base isolation construction. The results of computer simulation using ANSYS® software have shown that the rubber bearing base isolation gave vibration response in lateral motion.
Ultrathin Mica and Graphite Cantilevers Enhanced Photoacoustic Spectroscopy – towards Modelling of Acousto-mechanical Properties
Authors: Jan Suchánek , Michal Dostál , Pavel Janda , Zdeněk Zelinger , Jaromír Chalupský , Jan Wild 
Published: May 2020

Abstract
In this article, we present the concept of probing of the acousto-mechanical properties (e.g. spring constant, resonator quality factor) of thin 2D or 2D like samples (i.e., samples with one dimension at least 2 orders of magnitude smaller than the others). Samples prepared from highly ordered pyrolytic graphite and muscovite with thickness under 1 μm and other dimensions in the mm range are used for this purpose. These samples are employed in photoacoustic spectroscopy as the pressure sensitive elements and its movement is monitored by a He-Ne laser beam reflected from the surface of these samples onto a position sensitive detector. The concept includes the following steps: 1) development of the method of preparation of thin samples from layered materials 2) development of the experimental approach for data collection 3) derivation of theoretical behavior of photoacoustic response of the samples and 4) development and application of a model on experimentally acquired data.
Diamond-like Carbon Thin Film Coating for Application on Heterojunction Solar Cells by ECR-CVD System
Authors: Srisantirut Tanawit , Pengchan Weera , Phetchakul Toempong 
Published: May 2020

Abstract
Diamond-like Carbon (DLC) film has the ability to change the refractive index value achieved high transmittance for potential applications of antireflection coating. DLC films were deposited on heterojunction solar cells by the ECR-CVD (Electron Cyclotron Resonance Chemical Vapor Deposition) method using Acetylene (C2H2) and Argon (Ar) gases. DLC coating affects ITO (Indium tin oxide), causing the electrical and resistivity of heterojunction solar cell vary according to the coating time. The surface and thickness of the DLC films was measured with an atomic force microscope. Illuminated I-V characteristic was investigated by photo-I–V measurements. The suitable acetylene anti-reflection deposition time at 0.40 minutes. Therefore, heterojunction solar cell was fabricated on a substrate using the optimized DLC films as an anti-reflection coating and it obtained an increase efficiency of about 1%.
Fuzzy-set analysis of models of temperature deformation of thin-walled elements with elliptic boundaries in industrial and aerospace structures
Authors: Storozhev S V , Storozhev V I , Bolnokin V E , Hai Duong Minh , Mutin D I 
Published: May 2020

Abstract
A theoretical numerical-analytical fuzzy-set methodology to take into account the influence of scatter errors in the values of the initial physical, mechanical and geometric parameters on the estimates of the endogenous characteristics of temperature stresses in models of bending and flat temperature deformation of plate-type thin-walled structural elements with elliptical boundaries in industrial and aerospace equipment was developed. The methodology is based on the use of the alpha-level form of the heuristic principle of generalization in the transition to fuzzy-multiple arguments in the analytical representations of deterministic models for the estimated indefinite indicators of temperature bending moments and circumferential thermomechanical stresses at the boundaries of elliptical holes in thin plates. The results of calculations using the developed technique are presented. The proposed method is intended for use in theoretical and applied research on assessing the reliability and strength of thin-walled plate structural elements of aerospace engineering, industrial equipment and building structures under thermomechanical influences for conditions of uncertainty.
The friction surface destruction mechanism in a magnetic field
Authors: Burdo G B , Bolotov A N 
Published: May 2020

Abstract
The paper considers the mechanism of forming and developing brittle (quasi-coarse) cracks in a sample of ferromagnetic material in a magnetized state. It is shown that the external magnetic field affecting friction surfaces has the most significant effect on the wear process if the cracks open perpendicular to the magnetization vector. The paper describes the criterion of spontaneous crack growth in brittle materials taking into account magnetostatic energy.
Basic laws of filled polyaluminosilicate polycondensation used in printed circuit boards of power electronic spacecraft devices
Authors: Ivanov A A 
Published: May 2020

Abstract
Filled fractal aluminosilicates have been synthesized by a sol-gel method. Optimal conditions to obtain aluminosilicate gels have been determined. The obtained samples have been studied by IR spectroscopy, X-ray phase analysis, transmission electron microscopy, and the du Nouy method. The studies have shown the presence of chemically unbound –OH groups in the aluminosilicates. The effect of the amount of polymer matrix filled with highly dispersed filler powder and medium acidity on the adhesive strength of the dielectric layers applied on aluminum bases by 3D aerosol printing used in printed circuit boards of power electronic spacecraft devices has been studied by means of the du Nouy method.
Electrochemical technology for the formation of heterogeneous metal structures with increased corrosion resistance
Authors: Kireev S Yu , Kireeva S N , Glebov M V 
Published: May 2020

Abstract
Research into corrosion resistance of multilayer materials obtained by the method of potentiostatic pulse electrolysis was conducted. The purpose of the work was to select materials for the creation of multilayer steel coatings with high corrosion resistance, as well as to develop technology for their formation. The formation of galvanic coatings was carried out in stationary and potentiostatic pulse electrolysis modes. The study of corrosion resistance was carried out by accelerated methods in solutions simulating the marine environment. Corrosion resistance of samples made of St3 steel coated with nickel and zinc-nickel alloys of different compositions when using various electrolysis modes was studied. It has been experimentally proved that the potentiostatic mode of pulse electrolysis allows the formation of galvanic coatings with a zinc-nickel alloy of various compositions from one electrolyte. Based on the study of electrode potentials of coatings in various media, the composition of the outer and inner layers of a multilayer heterogeneous structure was substantiated. It was experimentally proved that the formation of multilayer coatings on the surface of steel could significantly increase the protective properties of these coatings. It was theoretically justified that the materials of the layers should have different values of electrode potentials, and the inner layer should have a more negative value of the potential than the outer one has.
Control of spacecraft waveguide dynamic behavior by means of support arrangement
Authors: Kudryavtsev I V , Brungardt M V , Nikitina S N , Kolotov A V , Rabetskaya O I 
Published: May 2020

Abstract
The most important parameters that determine the dynamic behavior of the waveguide in orbit are the first natural vibration frequency and the critical compressive force at which the stability of the waveguide structure is lost. This paper deals with the selection of the type and location of the outermost and intermediate supports for a single waveguide between two microwave units to provide the required values of the first natural vibration frequency and critical compressive force. The most common support arrangement schemes and their corresponding coefficients for equations defining the first natural frequency and minimum critical compressive force are given. For the calculation, the analytical dependencies of beam vibration theory and stability theory are used, which allowed to obtain simple equations and to comprehensively assess the influence of various factors on the obtained results. The results can be used in the design of any extended structures to ensure their dynamic behavior by means of support arrangement.
Structure and properties of hot-deformed powder steels microalloyed by aluminium
Authors: Dorofeyev V Y , Sviridova A N , Berezhnoy Y M , Bessarabov E N , Kochkarova K S , Pustovoit V N , Sviridova S V 
Published: May 2020

AbstractThe feasibility of cohesion degree enhancement, mechanical properties, and contact durability of powder forged steels due to microalloying with aluminum was studied. Unalloyed iron powders with various impurity contents, as well as atomized powder of low-alloy chromium-molybdenum steel, were used as the basis for the producing mixtures. Aluminum was doped as ferroaluminum. Specimens for mechanical and fatigue tests were produced by powder forging. Post-heat treatment was carried out according to two flow routes. The first flow route included carburizing, hardening and low tempering. The second flow route corresponded to high-temperature thermomechanical processing, which was carried out immediately after the completion of hot repressing porous preform. It was found that doping aluminum microadditives in hot-deformed powder steels provides the feasibility of increasing bending strength, impact strength and fatigue life under contact or low-cycle loading. This is associated with an enhancement of the conditions for interparticle joining during hot forging due to the generation of interlayers of ferrite in the interparticle zones as well as to the activation of cohesive interactions as a result of accelerating the process of dynamic recrystallization
Obtaining of tungsten nanopowders by high energy ball milling
Authors: Ozolin A V , Sokolov E G , Golius D A 
Published: May 2020

Abstract
The objective of the work is identifying the modes of ball milling of the W16,5 and PWT grade tungsten that ensure obtaining nanosized powders. Milling was performed with the AGO-2U planetary-centrifugal mill for 5, 15, 60, and 120 min at the carrier rotation frequencies of 400, 800, and 1000 rpm. After milling, the shape and size of tungsten powder particles was studied by scanning electron microscopy. The effect of work hardening and aggregation on milling of the powders has been demonstrated. As a result of ball milling, nanoparticles of tungsten sized from 25 nm have been obtained. It has been found that the minimum size of particles is achieved at the carrier rotation frequency of 800 rpm and milling duration of not less than 60 min.
Technologies and software for the regional catalog of Russian spacecraft satellite data
Authors: Kadochnikov A A , Yakubailik O E 
Published: May 2020

Abstract
The results of research and development devoted to the creation of technologies and software for the satellite data catalog from Russian spacecraft, formed at the Regional Center for Remote Sensing of the Earth in Krasnoyarsk, are examined. The created software package provides a full cycle of operations with satellite data, including their downloading from the Roscosmos Geoportal, pre-processing, archiving, conversion and visualization operations using a specialized geographic information web system. Practical experience with the data provider revealed a number of problems in the source information, which were taken into account when creating the software. In particular, some files were damaged (files are filled with zeros or have an incomplete size), some files in the data folder were missing, the names of files and directories did not meet the declared standards, and so on. Separately, we should pay attention to significant delays in data delivery, which reached six months or more. These problems were taken into account when creating the software.
Technology of producing nanomaterals and their use
Authors: Ospanbekov E A , Aitasov T T , Kairatuly A , Ismailov D V , Partizan G , Kerimbekov D S 
Published: May 2020

Abstract
This work is devoted to the technology for producing nanomaterials, in particular, the method of arc synthesis in helium medium under certain optimal conditions with a maximum yield of material, as well as their practical application as additives, which improve anti-corrosion properties. In this work, we used the extraction of fullerenes using the Soxhlet apparatus, which is designed to evaporate toluene from fullerene-containing sludge. Carbon nanostructures of a mixture of fullerenes C60 and C70 were obtained at a current of ~ 200 A, studied using Raman spectroscopy and optical microscopy at the National Nanotechnology laboratory at KazNU named after al-Farabi.