bluuebunny/crossref_metadata_2025 huggingface dataset:
Successional and seasonal changes of leaf beetles and their indicator value in a fragmented low thorn forest of northeastern Mexico (Coleoptera, Chrysomelidae)
Authors: Sánchez-Reyes Uriel Jeshua , Niño-Maldonado Santiago , Clark Shawn M. , Barrientos-Lozano Ludivina , Almaguer-Sierra Pedro
Published: February 2019

Leaf beetles (Chrysomelidae: Coleoptera) constitute a highly diverse family of phytophagous insects with high ecological relevance, due to their host plant specificity and their close association to vegetation variables. Therefore, secondary succession and seasonal changes after loss of vegetal cover will have a significant influence on their community patterns. Accordingly, responses of leaf beetles to such environmental heterogeneity make them a suitable taxon for monitoring disturbance, which is more important for endangered habitats such as the low thorn forests (LTF) in northeastern Mexico. We conducted a study in a LTF fragment in order to assess the effects of secondary succession and seasonality on leaf beetle communities, as well as to quantify the importance of Chrysomelidae as an indicator taxon. Landsat scenes were used for delimiting a successional gradient, in which four succession categories were selected: four years, 17 years, and 31 years since loss of vegetal cover, and conserved areas. Eight plots of 100 m2were randomly delimited in each category; plots were sampled monthly, using an entomological sweep net, from May 2016 to April 2017. In total, 384 samples were collected by the end of study, from which 6978 specimens, six subfamilies, 57 genera, and 85 species were obtained. Species richness was higher in early succession areas. Abundance declined significantly from early successional to conserved areas, but the conserved areas had the higher diversity. Furthermore, differences in abundance were significant between rainy and dry seasons in areas of four, 17, and 31 years of succession, but not in conserved areas; also, all categories had a similar abundance during the dry season. Intermediate (17 and 31 years) and conserved areas differed in the season of higher diversity. Regarding inventory completeness, it was close to or above 70 % for all comparisons, although it was very low for the 17-year category during the rainy season. Faunistic similarity was higher between intermediate categories. A total of 24 species had a significant indicator value. Effects of succession time and seasonality on leaf beetle communities are here quantified for first time in LTF forests. Influences of environmental heterogeneity and intermediate disturbance are discussed as main drivers of the results obtained. Several leaf beetle species are proposed that could be useful for monitoring succession time and secondary LTF vegetation in northeastern Mexico. However, studies must be replicated at other regions, in order to obtain a better characterization of disturbance influence on leaf beetles.
Nanostructured Yttrium Oxide Obtained by Hydrolysis of Yttrium Sulfate
Authors: Avdin Viacheslav V. , Trunova Valeria V. , Bulanova Aleksandra V.
Published: February 2019

Modern functional metal oxide materials are based upon the use of nanostructured particles. In recent years materials on the basis of yttrium oxide find ever-widening application. The properties of yttrium oxide depend heavily on precursors and synthesis conditions. One of the poorly investigated precursors is yttrium sulfate. The study discusses the products of alkaline hydrolysis of yttrium sulfate obtained by the sol-gel method. The influence of the synthesis pH on morphological, thermal and structural properties of compounds has been examined. Formation of non-stoichiometric compounds occluding counter-ions of the reactant salts in their structure has been revealed. The nanostructured hydrolysis products are formed, which increase their specific surface at annealing and retain their morphology and sizes. The obtained results give grounds to expect using yttrium sulfate as a precursor for synthesis of structured yttrium oxide.
The Structure of Multi-Layer Composite Material Obtained by the Method of Diffusion Welding
Authors: Dildin A.N. , Gerasimov V.Yu. , Zaitseva O.V.
Published: February 2019

Creation of reliable and durable composite materials made of components with different properties is an urgent task. Such materials include multilayered steel. Alternation of a large number of heterogeneous layers leads to a set of properties that are unattainable for homogeneous steel. Production of such composite materials faces many problems. The use of diffusion welding has created a number of composite materials based on steels of different composition, and their properties allow you to use them in the manufacture of cutting tools. The purpose of this work was to study the structure of multilayer composite materials obtained with the help of diffusion welding and the study of the heat treatment effect on the material structure. During the study, the structures of samples of six different composite materials were studied after annealing and after quenching of the metal. The study showed that the studied materials have a pronounced layered structure with a sharp transition boundary from one layer to another. The technology used in the production of composites ensures the actual absence of the transition zone and the absence of such frequent diffusion welding defects as stratifications, pores, oxide inclusions, etc. The study found that during heat treatment process sizes of carbide inclusions in the composite layers decreases, and their number increases.
Features of the Formation of Structure and Phases in Single-Crystal High-Temperature Alloys and their Effect on Mechanical Properties
Authors: Popov Nikolay A. , Lugovaya Kseniya I. , Zhilyakov Arkadiy Yu.
Published: February 2019

Features of the structure and phase transformations in single-crystal nickel alloys 1, 2 after long high-temperature exposures were considered in this paper. The results and studies of the residual mechanical properties of alloys after exposure are given. Nanophase hardening of single-crystal heat resistant nickel alloys was also considered. The method of heat treatment of single-crystal high-temperature nickel alloys was developed based on the studies. It provides an increase in the strength properties of alloys by 20...30%, due to the formation of bulk nanophases (γn+ γ'n). The data obtained on structural and phase changes in high-temperature nickel alloys make it possible to evaluate the stability of the structural state of alloys.
Influence of pH and Synthesis Duration on the Composition and Thermal Behavior of Hydrolysis Products of Lanthanum Nitrate
Authors: Avdin Viacheslav V. , Mosunova Tatyana V. , Bogdanov Artem V.
Published: February 2019

The study investigates the hydrolysis products of lanthanum nitrate, obtained at various pH values and times of the hydrolytic agent addition. It has been found that the structure formation of lanthanum oxyhydroxide is accompanied by capturing the admixture ions, namely, the anions of the reactant salt and carbonate ions. It has been shown that thermal decomposition of the hydrolysis products proceeds in four stages for faster hydrolysis. If hydrolysis is slow, the intervals merge together into three stages of thermal decomposition. The hydrolysis products of lanthanum nitrate, heated up to 500...550 С, actually consist of lanthanum oxide containing nitrate and carbonate, chemically bonded to the oxide matrix, in its inner regions. The composition of the synthesized samples changes if pH varies. The minimal content of admixture ions can be observed at the synthesis pH > 10, if the time of the hydrolytic agent addition equals 24 h. The obtained results suggest that lanthanum nitrate can be used as a precursor for synthesis of structured lanthanum oxide.
Ceramic Proppants Based on Ultrabasic Rocks of Kazakhstan Chromite Ore Deposits
Authors: Biryukova A.A. , Dzhienalyev T.D. , Boronina A.V.
Published: February 2019

The purpose of the work is the obtaining of magnesium silicate ceramic proppants, based on ultrabasic overburden rocks of Kempirsai deposits of chromite ores (Kazakhstan). The chemical and mineralogical composition of ultrabasic overburden rock was studied by chemical, microscopic and X-ray diffraction analyzes. It is established that the main mineral of ultrabasic overburden rocks is serpentine, present in the form of fibrous chrysotile and lamellar antigorite. In the impurities are iron oxides and hydroxides, chrome spinel, carbonates, quartz. Assessment of the use of overburden rocks as a raw material for the production of ceramic proppants was carried out. The sintering interval of overburden rocks was determined at 1280-1300 °C. The sintering firing optimum temperature of ceramics, based on this type of raw material is 1300 °C. It is established that to harden the structure of magnesium silicate ceramic it is necessary to activate the raw material thermally at a temperature of 1000 °C. The influence of binder type on the properties of magnesium silicate proppants, based on the Kempirsai serpentinites was studied. Magnesium silicate proppants, based on ultrabasic overburden rocks, were obtained with the following properties: apparent density – 1.6 g/cm3, strength resistance (52 MPa) – 14%, sphericity and roundness – 0.8; chemical resistance (hydrochloric acid) – 98%, static strength of the fraction 16/20 - 72–118 N/granule. The field of application is oil and gas production, metallurgy and ceramic industries.
Destruction Patterns of X70 Steel Sample, Possessing Cracks of Corrosion-Mechanical Origin, under Cyclic Loading
Authors: Nasibullina O.A. , Gareev A.G.
Published: February 2019

Most of the structures, parts of machines in the process of operation are subjected to the action of cyclically changing loads, such changes can be judged by the fatigue of the metal. In addition to the influence of mechanical stresses during the service, corrosive environment affects metal structures, machine parts, which leads to the process of gradual accumulation of damage. Corrosive media leads to a decrease in durability. The paper presents results of fatigue tests on a sample of steel X70, selected from the focal zone of destruction of the main gas pipeline. The sample under investigation had numerous cracks typical for corrosion-mechanical destruction. It is shown that with an increase in the number of loading cycles, the electrode potential of the metal decreases, which leads to a decrease in its thermodynamic stability. With the growth of the crack, there is a decrease in the potential, which is not compensated by the relaxation processes. Results of the regression analysis showed that the correlation coefficient is r = 0.99, using the three-parameter logarithmic function.
Methods for Improving the Efficiency of Steel Modifying
Authors: Bakin Igor V. , Mikhailov Gennady G. , Golubtsov Valery A. , Ryabchikov Ivan V. , Dresvyankina Ludmila E.
Published: February 2019

In connection with the need to improve the quality characteristics of metal products, metallurgists are faced with the task of finding new effective methods for secondary steel processing. It is known that the use of simple, two-component materials does not significantly improve the quality of the metal. Complex modifiers with alkaline-earth elements are increasingly used for the modifying processing of steel. These modifiers allow to influence both the metal structure and the shape, phase composition and physical properties of nonmetallic inclusions. At the same time, it is known that barium and strontium practically do not dissolve in steel and are removed from the alloy in the extremely short time. The ability of barium and strontium alloys to deoxidize and desulphurize is low because of the large atomic mass of these elements. The modifying effect of alkaline-earth elements on the properties of steel is undeniable. This effect can be explained by the ability of barium and strontium to affect the magnitude of inter-phase tension in the event of contact with the phase boundary. The purpose of this work was to generalize the industrial experience of using multicomponent alloys with alkaline-earth elements for modifying of steel. Data on the effects of alloys with alkaline-earth elements on the properties of metals are given, as well as technological features of the use of complex alloys with alkaline-earth metals in steelmaking. Thus, it is noted that in conditions of large-scale steelmaking, a very important factor is the limited time in time of the modifying effect of alloys with alkaline-earth metals, which dictates the necessity of transferring the process of modification directly to casting.
Investigation of Grain Anisotropy on Surface Area between Carbon Steel Wire and Die at Drawing
Authors: Stolyarov Alexey , Kamalova Guzel , Polyakova Marina
Published: February 2019

Drawing is characterized by non-uniform character of plastic deformation, which is transferred from the die to the processed wire. Such impact causes specific change of wire microstructure. In the surface area the thin layer with highly deformed grains is observed. It is important to measure the thickness of this thin layer. For this purpose it is proposed in this paper to use the value of coefficient of anisotropy, which is calculated as the ratio of mean quantity of phase particles, crossed by secant line perpendicular to deformation axis on the unit of secant line length to the mean quantity of phase particles, crossed by secant line parallel to deformation axis on the unit of secant line length. Distribution of coefficient of anisotropy, both for low and high carbon steel wire after drawing, was obtained by Thixomet PRO software. It made it possible to calculate the thickness of highly deformed area automatically taking into consideration the difference of steels microstructure.
Components of the GdOCl - GdCl3 • 6H2O System Identification and Determination by the Raman Spectroscopy
Authors: Zakir'yanova Irina D. , Vovkotrub Emma G. , Bobrova Ksenia O.
Published: February 2019

The Raman spectroscopy is used to identify and determine the content of the components of a GdOCl − GdCl3 • 6H2O mixture. It can be used for analytical control of the composition and detection of undesirable oxygen-containing impurities in chloride reaction media in the preparation of rare-earth metals.
Influence of Thermal Exposure on the Structure and Phase Composition of Aluminized Layer Obtained by Explosion Welding and Hot-Dipping Process
Authors: Shmorgun Victor Georgievich , Pronichev Dmitriy Vladimirovich , Kulevich V.P.
Published: February 2019

It is shown that for the formation of Fe2Al5 intermetallic coatings on the steel surface the aluminized layer obtained by explosion welding must be subjected to a double heat treatment (660 °C, 3 h + 640 °C, 3 h). The first heat treatment ensures the necessary size of the diffusion zone, and the second leads to the formation of a main crack at the interface of Fe2Al5 and FeAl3 intermetallides, which allows to separate the unreacted layer of aluminum and form a coating with hardness of 10 GPa. To form Fe2Al5 intermetallic coating on the steel surface, the aluminized layer, which is immersed in the melt, must be heat treated at 800 °C. The alloying of the diffusion zone by Si and Cu with the replacement of aluminum by the AK12M2 alloy leads to a decrease in the thickness of the diffusion zone and the appearance of additional phases of Al7Fe2Si and (Al,Si)5Fe3 in its composition. The duration of the subsequent heat treatment at 800 °C for complete dissolution of the surface layer increases the hardness of the resulting coating on the basis of a solid solution of Si in Fe2Al5 is 7.5-8 GPa.
Powder Diffraction and Dilatometric Study of SrFe12O19
Authors: Gudkova Svetlana A. , Uchaev Danil A. , Vinnik D.A.
Published: February 2019

Strontium hexaferrite is a well-known material, due to its application in microelectronics. This paper is devoted to strontium hexaferrite single crystals, obtained by the spontaneous crystallization technique with sodium based flux. SrFe12O19 crystals were grounded, pressed to the tablets, and crystals cell parameters were measured by thermal X-ray diffraction technique. Coefficient of thermal expansion calculated from the X-ray thermal diffraction data is in a good agreement with dilatometric measurements.
Ball-Milling Stimulated Mechanochemical Processes in the System “Titanium-Toluene”
Authors: Kanunnikova Olga M. , Aksenova V.V. , Dorofeev G.A.
Published: February 2019

The present work deals with the investigation of the transformations of the solid and liquid phases at high energy planetary ball milling of toluene together with titanium powder. The sequence of structural toluene transformations using FT-IR spectroscopy was investigated. Phase constitutions and morphology of ball milled titanium powders were studied by X-ray diffraction and scanning electron microscopy. It is shown that mechanically induced destruction of toluene occurs by the mechanism of catalytic cracking. During ball milling, concentration of aromatic hydrocarbons in the liquid phase decreases, at the same time the content of alkenes, cycloalkanes, and isoalkanes increases. The main solid products of the mechanosynthesis were cubic and hexagonal titanium carbo-hydrides.Evolution of lattice parameters, crystallites sizes, and micro-stresses of the solid phases during ball milling as a function of the mechanical energy dose have been discussed.
Improving the Strength of Abrasive Wheels and Optimizing the Control over the Strength of Composite Abrasive Materials
Authors: Chaplygin Boris A. , Shirokov Viacheslav V. , Lisovskaya Tat'yana A. , Lisovskiy Roman A.
Published: February 2019

The strength of abrasive wheels is one of the key factors affecting the performance of abrasive machining. The paper discusses ways to improve the strength of abrasive wheels. The stress-state mathematical model presented herein is a generalization of the existing models. It is used herein to find for the first time that there are numerous optimal combinations of the elastic modulus and reinforcing material density, which result in the same minimum value of the objective function. It is found out that increasing the radius of the reinforcing component while also optimizing the mechanical properties of its material may increase the permissible breaking speed of the wheel several times. We herein present a regression equation and a nomogram for finding the optimal combination of control factors.
Conventional methods for testing the mechanical properties of materials, which have been proven reliable for testing metals and alloys, are not as reliable for testing abrasive materials, as the test results they generate are not sufficiently stable or accurate. We therefore propose an alternative method that does not require any special equipment or special studies.
Modeling of Material and Heat Balance of Ferromanganese Blast Furnace Smelting Using Computer Environment Lazarus
Authors: Gafarov M.F. , Senin A.V. , Gafarova E.A.
Published: February 2019

A mathematical model of the overall material and thermal balance of the ferromanganese smelting in blast furnaces of JSC "Satka Iron Smelting Works" is presented. Completeness of chemical reactions was taken into account in calculations based on thermodynamic analysis and technological data. Data on the thermochemical properties of substances; on the thermal effects of chemical reactions; on the degree of carbon graphitization in coke; on the heats of formation of metallic and slag solutions; on the thermochemical characteristics of ferromanganese, slag and gas phase were systematized and corrected. Heat losses for a particular type of blast furnaces are taken into account. The mathematical model is implemented in the computer program environment Lazarus. Test calculations of material and heat balances of ferromanganese blast furnace smelting were carried out. The calculation results correspond to the technological data. The developed software allows you to manage quickly the production process, to predict the optimal composition of charge materials for obtaining a product of a specific composition without experimental smelting. The software is used in the "consultant" mode at the JSC "Satka Iron Smelting Works".
Determination of Polymorphic Transformation Temperature for Alloy VT8
Authors: Zavartsev Nikita A. , Kareva Nadezhda T.
Published: February 2019

The temperature of polymorphic transformation (Tpt) has been determined for accurate composition of two-phase titanium alloy which has been marked like VT8 through different ways: the method of trial quench and with the help of dilatometric and differential thermal analyzes. The close values of Tpt have been received. Herewith the phase composition has been estimated qualitatively and quantitatively for the hardened samples of alloy VT8 using optical and scanning electron microscopes and the chemical composition with the help of the micro X-ray spectral analysis. The influence of the quenching temperature on the hardness has been investigated. Also, the hardness of the individual structural components and alloy VT8 as a whole unit has been measured. Hardness curves are based depending of the quenching temperature; the results are displayed in tabular and graphical form. The coefficientkhas been found for the calculation of allotropic transformation temperature for this alloy using the known temperature of hardening and quantity of preserved α-phase of hardened structure. The album of the microstructures after quench with different temperatures has been created, this album will allow to reduce the duration of preliminary works for finding specific temperature of polymorphic transformation in production conditions for each new batch of alloy VT8 with another chemical composition (but within the vintage), knowledge of which is necessary for setting the temperature regime of treatment.
Direct Reduction of Iron from Crystal Lattice of a Complex Oxide
Authors: Salikhov S.P. , Roshchin A.V.
Published: February 2019

This work studied a decomposition and reduction of complex carbonate (sideroplesite) siderite lump ore from the Bakal’s deposit. The decomposition caused formation of complex oxides (Fe,Mg,Mn)O and (Fe,Mg,Mn)O·Fe2O3, and it preceded the Fe reduction; the weight loss during the decomposition process reached about 32%, being followed by the formation of a large number of pores. As the pores and micro-pores provide deep penetration of the carbon monoxide in the bulk of the ore lumps, it seemed that the pores would allow reduction of this ore without difficulties. However, during reduction experiments it was discovered that the distribution of the reduction process and formation of the metal phase were not connected with the pores’ distribution. The reduction process developed via an electrochemical mechanism, and the channels of the distribution of the reduction process were oxides of metals which were difficult to reduce under the presented experimental conditions; these oxides were mostly represented by the magnesia and silica compounds. The high rate of the iron reduction from the complex iron-manganese-magnesium oxides was explained by the high rate of distribution of the negatively charged anion vacancies forming on the surface of the oxide, due to reaction with a reducing agent.
Solid-Phase Reduction of Iron from Suroyam Titanomagnetite Ore during Metallization in Rotary Kiln
Authors: Smirnov K.I. , Salikhov S.P. , Roshchin V.E.
Published: February 2019

In this work the solid-phase reduction of iron from the Suroyam titanomagnetite ore was studied during metallization in a rotary kiln. The technique of preparation of the ore and reducing agent for metallization and the process of continuous processing of materials in a rotary kiln were described in detail. For metallization the temperature was chosen 1150°C, due to low melting point of apatite from one of the components. The results of the electron microscope analysis of the initial ore and samples subjected to metallization for 1-hour reduction time were presented. The reduction of iron occurred despite absence of pores and contact with a reducing agent in the grains of titanomagnetite. Iron in the grains of titanomagnetite surrounded by apatite was reduced to wustite; whereas, iron surrounded by clinopyroxene was reduced to metallic iron. This indicated the effect of composition of the gangue materials on the reduction process.
Hydrochemical Investigation of Dissolving Sulfide Gold-Bearing Raw Material of Uderey Deposit
Authors: Dizer Oleg A. , Rogozhnikov Denis A. , Naboichenko Stanislav S.
Published: February 2019

This article describes a method for the hydrochemical dissolution of a sulfide gold-bearing raw material from the Uderey’s deposit using nitric acid. The chemical and phase compositions of the studied material, mainly represented by compounds of silicon, sodium, arsenic, iron and sulfur, are investigated. Phase composition: pyrite, arsenopyrite, quartz, thenardite. The dependences of the influence of temperature, time, and the liquid to solid ratio on extracting the main components in the solution were determined by methods of mathematical experiment planning. The calculated values ​​of the determination coefficients testify to the adequacy of the chosen two-level model. The optimum parameters of the process were obtained: L/S ratio = 8; the nitric acid concentration was 6 M; experiment duration was 75 minutes.
Improvement of Stirred Tank for Aluminum Hydroxide Seeded Precipitation
Authors: Chernyshov V.B. , Shoppert Andrey A. , Sarapulova V.I.
Published: February 2019

The known designs of tank for precipitation of aluminum hydroxide from sodium aluminate solution, used in the production of alumina are considered, and the improvement of the design of the precipitator with mechanical mixing is proposed, which allows to intensify the process of precipitation and to avoid strong caustic module of the solution changes.
Nanostructured Materials in Preparation Casting Alloys
Authors: Znamenskii L.G. , Franchuk A.N. , Yuzhakova A.A.
Published: February 2019

The article deals with technologies of refining and inoculating casting alloys with the use of nanostructured diamond powder, as well as stimulation technique on molten metal including processing of the liquid alloy with nanosecond electromagnetic pulses. The developed method of cast iron inoculation allows to eliminate the flare and to increase the physical and mechanical properties of the castings through the grain refining and the decrease of chilling tendency during crystallization of the liquid alloy. Inoculating of aluminium alloys by high-melting particles of a nanostructured diamond powder leads to the grinding of structural constituents, including conditions for dispersing hardening intermetallics during postbaking of such castings. As a result, foundry and physicomechanical properties of castings are significantly improved.
Specialty of Сarbon-Carbid-Silicic Mixture Using (UKKS) as Substitute of Re-Carburizing Agent and Ferrosilicon for Grey Iron Melting
Authors: Kukartsev Viktor A. , Kukartsev Vladislav V. , Tynchenko Vadim S.
Published: February 2019

In the transition to modern high intensive processes of smelting there had been reversed technologies structures to get carbon content in cast iron. A re-carburizing agent, that can be one of the most significant reasons of occurrence of defects of the cast, and deformed metal and decrease of the level of properties have been identified. There was not only made the decarburizing agent of modern technology of production of pig-iron essential element (particularly synthetic), but also resulted in many of variants of its realization from the standpoint of level decarburizing, type, using re-carburizing method of decarburizing technological phase, where enter of carbonaceous materials. Particularly sharply process of execution re-carburizing influences receipt of synthetic pig-iron in induction crucible furnaces of industrial frequency from metal works, which contained 80-90% of steel breakage. Then, it is necessary to raise the content of carbon from 0,3 to 3,0-3,8% (depending on the pig-iron mark). It forces foundry enterprises to approach with big care at a choice of existing materials, which it is possible to use as decarburizing and to verify carefully, which is appearing at the market. In work application there are considered variants of using carbon-carbide-silicon mixture UKKS-31 at melting of grey pig-iron in induction, crucible furnaces, intended for pig-iron melting. The cost comparison is presented between traditional technology and with using mix UKKS-31.
Development and Application of Tube End Forming Process with Combined Swaging and Local Differential Pre-Heating
Authors: Tkachov R.O. , Kukhar Volodymyr V. , Klimov Eduard S. , Prysiazhnyi Andriy H.
Published: February 2019

The performed research helped to develop and implement a new process of manufacturing small high pressure cylinders, in which the operation of pressing of tubular blanks with preliminary induction heating of the deformation zone. A two-layer inductor was designed and an industrial unit for preliminary differentiated induction pre-heating for the developed technological process. The forming rate was determined, ensuring preservation of the specified temperature difference and manufacturing of deformed tube end in accordance with the requirements for its geometry. Heating die-blocks were designed for blanks deforming for application in manufacturing of diameter, allowing keeping the necessary temperature gradient at deforming. Developed technological lubricants can be used for obtaining high quality products, increase in labor protection and die-blocks durability.
Stress-Strain State of a Plastic Layer under Compression by Two Rigid Parallel Rough Plates
Authors: Dilman Valery L. , Karpeta Tatyana V. , Dheyab Aws Nedal
Published: February 2019

The stress-strain state of a plastic layer under compression by two rigid parallel rough plates under conditions of plane deformation is investigated. The hypothesis of flat sections is used. Tangential stresses are found in the part of the layer under load, as an approximate solution of the system of equations of the stress-strain state of the compressible layer. The solution is obtained in analytical form. On this basis the velocities of the points of the layer are calculated in the analytic form. The size and shape of the free surface are calculated depending on the thickness of the layer. The coefficients of this dependence are determined by recurrent relations. On this basis, an algorithm for finding the shape of a free surface is found. The computational experiments are provided and the results are compared with results obtained with FEM and ANSYS.
Study of Force and Kinematic Parameters of the Low-Waste, Zero-Draft Hot Forging of Welding Neck Flanges on the Basis of a Combined Expansion-Extrusion Deforming Procedure
Authors: Radionova Ludmila V. , Ivanov Vasily A. , Strugov S.S.
Published: February 2019

This paper demonstrates the development of a technology for low-waste zero-draft hot forging of axisymmetric parts, in particular, welding neck flanges, on the basis of an expansion-extrusion deforming procedure. In this study, we carried out a process simulation by means of DEFORM 3D for a qualitative evaluation of the plastic yield. Based on the simulation results, the method was proven feasible, and we set forth the goal to prepare the process and design guidelines for further industrial application. The region of plastic deformation was determined, and a general view of the function for determining kinematic parameters was given according to A.L. Vorontsov’s procedure. The force parameters of the zero-draft hot forging process by the combined expansion-extrusion procedure were analyzed by studying the kinematic conditions of the forging. The general function for determining the force parameters was found.
Structure and Mechanical Properties of Electrical Copper Wire Processed by Coarse and Medium Drawing
Authors: Illarionov Anatoly G. , Loginov Yuri N. , Stepanov Stepan I.
Published: February 2019

The evolution of structure, strength and ductile properties of M001 grade copper wire after the coarse and medium drawing were studied using the metallography, micro-indentation and tensile testing. Coefficient for evaluation the ultimate tensile strength from the micro-indentation data was determined. The formula was proposed for estimation the dislocation density the stress strain curves and from the data on the grain size in the transverse section of the wire.
Research on Welding and Processing Behavior of Electrodes and Features of their Application in "Wet" Underwater Arc Welding
Authors: Muktepavel Voldemar , Murzin Victor , Karpov Vyacheslav , Kurakin Arthur
Published: February 2019

Three brands of special electrodes for underwater welding were analyzed: LKI-1P, EPS-AN, UW-EZ-2. Experimental data on welding and processing behavior of these types of electrodes in the conditions of underwater arc welding were obtained: melting factor, metal deposit factor and losses. Experiments have been performed to determine the value of the arc breaking length of electrodes when welding under water. A comparative analysis was made with UONII-13/55 electrodes when welding in air conditions.
Kinetics of Residual Stresses in a Welded Frameless Tubular Node
Authors: Tingaev A.K.
Published: February 2019

The results of experimental studies of the variation of residual stresses in a frameless tubular node of the offshore stationary platform (OSP) due to technological effects on the metal are presented. It is shown in the paper that the value of the tensile residual stresses in sheet rolled products with 20-50 mm of thickness reaches 80-65 MPa. As a result of the subsequent technological redistribution, the residual stresses change in magnitude and sign, and reach 0.8-1.2 of the yield strength of the base metal. The most unfavorable from the point of view of the serviceability of OSP are the tensile residual stresses in welded joints, the maximum value of which is 350...500 MPa. High temperature tempering after welding does not always lead to the desired result: in the heat-affected zone of the corner joints of nozzles mounting to the waist tube of the node, the residual stresses amount to 120-150 MPa. Preheating temperatures in the range of 120-1600С do not have a significant effect on the value of residual welding stresses. For more effective reduction of σrs , its value should be 200-4500С, depending on the thickness of the joined parts and the strength class of the steel.
Welding of Valve Steels of Different-Sized Cross Sections
Authors: Osipov A.M. , Bezgans Yu.V. , Lodkov D.G.
Published: February 2019

This paper considers the results of studies of the welded joints formation in conventional friction welding of pieces with different-sized cross sections. The features of the formation of joints associated with the asymmetry of the temperature field in the pieces are defined. The results of studies of the main parameters of the welding process are given which influence on the appearance, the microstructure of the joints and the valve after the stamp. The optimum parameters of the welding mode are set; recommendations are given.
Research on Plasma Electric Arc Granulation Processes of the Ural Region Mineral Raw Materials to Welding Materials for Submerged Arc Welding
Authors: Naumov Stanislav V. , Artemov Arseny O. , Belousov Kirill I.
Published: February 2019

This article offers a qualitatively new approach for production fused welding fluxes granules, based on the use of a plasma arc and the Ural region raw materials that have a particularly low content of harmful impurities. The processes of fused welding flux granules forming from the Ural region mineral raw materials under the impact of a highly concentrated energy source have been studied. A new fused welding flux for submerged arc welding is produced by plasma electric arc granulation, and has required shape and fractional, chemical and phase composition of the particles. This research presents experimental and theoretical studies of interaction processes of fine-dispersed batch from mineral raw materials with a highly concentrated energy source, aimed at obtaining new information about the basic patterns of the formation, structure and composition of resulting granules of functional materials, such as welding fused fluxes.
Technology and Properties of Composite Materials with Modifier of Chloride Aluminum
Authors: Yusupova Alsu A. , Medvedeva Galina A. , Bobryshev Aleksandr A.
Published: February 2019

The paper discusses the important issues concerning recycling of industrial sulfur waste and bottom ash. The process flow diagram was designed to form protective coatings on cement concrete by impregnation with molten sulfur, which featured high strength, performance properties and corrosion resistance. The process parameters were specified. The addition of bottom ash slag to cement concrete not only offers a means for recovering waste from thermal power stations, but also increases the material strength. Besides, the impregnation process provides low thermal conductivity for concrete while giving the material high heat insulation. A higher strength of the samples containing bottom ash slag results from a high dispersity and reactive surface of bottom ash slag. The paper investigates the influence of the electrophilic agent (aluminum chloride) on the properties of sulfur binder. It was shown that addition of aluminum chloride encouraged the formation of a more effective protective coating that gave the samples of cement concrete higher strength, density, water resistance. The electrophilic agent stimulated the synthesis process for inorganic sulfides and composite materials based on them. It was found that addition of the electrophilic agent (aluminum chloride) reduced the viscosity of molten sulfur significantly, which was attributed to the formed short-chain sulfur radicals. Such a melt has a relatively high penetration capability to ensure the formation of a high-quality protective coating.
Formation of Structure in Titanium Lightweight Structures Made by Selective Laser Melting
Authors: Borisov Evgenii , Popovich Anatoly , Sufiiarov Vadim , Polozov Igor , Orlov Alexey , Masaylo Dmitry , Sokolova Victoria
Published: February 2019

The results of the analysis of the plasma atomized powder material are shown. An analysis of the microstructure in lightweight constructions made of VT6 alloy by selective laser melting was carried out. The microstructure and mechanical characteristics of the obtained structures were studied before and after heat treatment. Measurement of grain size in the microstructural analysis gave a more complete picture of the state of the structure in different parts of the sample formed as a result of growing by selective laser melting, in a mesh and compact. In the course of the work, the peculiarities of the growth of grains in bars of the mesh construction are revealed depending on their location.
LASER toy-induced macular burn: An illustrative case
Authors: Elbarghathi Adam , Abdullah Ruwida
Published: February 2019

Introduction: Light amplification by stimulated emission of radiation (LASER) toys are widely available in the market with no clear information about their wavelength and hazardous effects. To be safe to the eyes, LASER should be classified <3b (according to international safety classification). Case History: We here report an illustrative case of macular injury post LASER toy direct exposure. A 12-year-old boy, previously known hypermetrope with left-eye (LE) amblyopia, presented complaining of drop of vision in the right eye (RE) after his colleague pointed a LASER toy directly over his RE. His corrected visual acuity (VA) was 5/60 (amblyopic) in the LE and 6/18 in the RE. The anterior segment was normal in both eyes. Fundus examination showed the LE to be normal, and the RE had a macular yellowish, oval-shaped lesion. Optical coherence tomography and fundus picture revealed central macular burn. Local and systemic corticosteroids were prescribed tapering over 9 days. After 1-week, the patient noticed some improvement in VA in RE to 6/9. Conclusion: LASER toys available in several markets are reported to be vision threatening and cause macular burn which responds partially to corticosteroids. More education and strict regulation of distribution and use of LASER toys and instruments is urgently needed.
Sodium-glucose co-transporter 2 inhibitor-induced euglycemic diabetic ketoacidosis in a Type 2 diabetes patient not absolutely insulin-deficient!
Authors: Mukthar Mamoun , Skaria Sijomol , Beshir Ahmed Ramadan , Elmalti Akrem
Published: February 2019

Sodium-glucose co-transporter 2 (SGLT2) inhibitors are the newest class of oral antidiabetic agents. In addition to glucose lowering, they have other advantageous effects on blood pressure and body weight. The use of those agents has increased exponentially after the emerging evidence of cardiovascular protection following the publication of the EMPA-REG OUTCOME study. Although they are relatively safe and effective, they are not without side effects. Perhaps, the most serious complication is euglycemic diabetic ketoacidosis (DKA). Several cases were reported in the literature. We describe a case of severe DKA in association with the use of an SGLT2 inhibitor (empagliflozin) in a 69-year-old male with type 2 diabetes who is not absolutely insulin deficient following knee replacement. The case highlights the increased risk of DKA and the importance of discontinuation of SGLT2 inhibitors before major surgery.
Выпуклые алгебры вероятностных распределений, индуцированные конечными ассоциативными кольцами
Authors: Yashunskii Aleksei Dmitrievich
Published: February 2019

Рассматриваются преобразования случайных величин над конечным ассоциативным кольцом операциями сложения и умножения. Для произвольных конечных колец строятся семейства алгебр распределений - множеств распределений, замкнутых относительно взятия сумм и произведений независимых случайных величин.
Calibración Automática en Filtros Adaptativos para el Procesamiento de Señales EMG
Authors: Salamea Palacios Christian , Luna Romero Santiago
Published: February 2019

En este trabajo se propone un filtrado adaptativo que incluye una etapa de calibración automática para la adquisición de señales EMG (Electromiografía). Se propone una técnica innovadora llamada “calibración automática” para minimizar el ruido provocado por el contacto de la piel con los sensores utilizados (electrodos) en condiciones de actividad física. Se utiliza filtrado adaptativo considerando que tanto la actividad física como la sudoración en personas son factores que alteran las condiciones de medición. La experimentación se ha realizado con personas que han desarrollado actividad física con diferentes condiciones de esfuerzo. Se ha utilizado la mejora relativa de la relación señal-ruido (RI-SNR) para comparar la técnica propuesta con filtros adaptativos que usan “ruido blanco” como señal de referencia. Este trabajo estuvo enfocado en los estimadores: Wiener, LMS y RLS, con mediciones realizadas antes y después de la actividad física. La técnica propuesta presenta una mejora de hasta un 45,49%, comparada con la correspondiente que utiliza “ruido blanco” para la calibración.
Optimización y Control de un Proceso de Mezclas Rundown para la Fabricación de Gasolinas
Authors: Gonzalez Martin Rafael , Morilla Garcia Fernando
Published: February 2019

La gasolina comercial es una mezcla de componentes obtenidos de la destilación del petróleo. El reto del Sistema de Optimización y Control es maximizar el margen económico del proceso utilizando la mezcla de componentes más barata, satisfaciendo la composición de las mezclas, los inventarios, la disponibilidad de las unidades de producción y las restricciones hidráulicas de las líneas. La complejidad de estos sistemas de mezcla ha ido aumentando debido a la competencia creciente en el sector, las refinería más competitivas realizan las mezclas con componentes que provienen directamente de unidad sin pasar por almacenamiento intermedio, método rundown, se disminuyen inventarios y se aumenta el beneficio. En este artículo se presenta un método innovador consistente en aplicar distintos niveles de automatización emulando la estrategia de control en cascada. Los resultados obtenidos en simulación han permitido aplicar el método propuesto en una instalación real, donde se ha podido contrastar la bondad del método y su generalización a un sistema con dimensionamiento real.
Estrategias de adaptabilidad estáticamente estables al cambio de terreno para un robot caminante de 6 extremidades
Authors: Sandoval Castro Xochitl Yamile , Castillo Castañeda Eduardo
Published: February 2019

Este artículo presenta la cinemática directa e inversa en posición de un robot caminante hexápodo, tomando en cuenta la pose del tórax. También se presentan tres estrategias de adaptabilidad al terreno que garantizan la estabilidad: orientación constante del tórax, estrategia geométrica y estrategia de emergencia. El diseño de las estrategias de adaptabilidad considera los parámetros geométricos y el peso de todos los elementos. La cinemática directa e inversa es esencial para redireccionar la postura del robot caminante. La estabilidad de las estrategias es evaluada con el margen normalizado de estabilidad energético (NESM). Las estrategias fueron simuladas en software especializado y se validaron experimentalmente.
Control Robusto de un Actuador Neumático Basado en la Estructura de Control con Compensación Activa de Perturbaciones para Seguimiento de Trayectorias
Authors: Rosas Almeida David Isaías , Cantú Cárdenas Jesús Armando , Ocampo Díaz Juan De Dios , Muñiz Valdez Héctor
Published: February 2019

Se propone una estrategia para resolver el problema de seguimiento de trayectorias en actuadores neumáticos inciertos y con medición parcial del vector de estado. La estrategia se basa en la estructura de control con compensación activa de perturbaciones (ADRC), que está formada por un observador de estado, un filtro pasa bajas y un controlador. En esta propuesta se utiliza un observador de estado discontinuo que estima el vector de estado completo y, utilizando el concepto del control equivalente, permite estimar los términos de perturbación presentes en la planta. El filtro pasa bajas se encarga de recuperar el control equivalente a partir de un término discontinuo del observador. Finalmente, el controlador tiene la estructura básica PD con un término adicional, que corresponde a las perturbaciones estimadas, y que tiene como fin compensar las perturbaciones reales en la planta. El rendimiento del sistema en lazo cerrado se evalúa mediante un índice de desempeño basado en la norma L2.
Aplicaciones Ada en Android con requisitos de tiempo real
Authors: Pérez Ruiz Alejandro , Aldea Rivas Mario , González Harbour Michael
Published: February 2019

Android es el sistema operativo más extendido en el ámbito de los dispositivos móviles. Su gran expansión y desarrollo ha provocado que exista un gran interés para utilizarlo en entornos con requisitos temporales. Este trabajo presenta un mecanismo para utilizar el lenguaje de programación Ada en el desarrollo de aplicaciones de tiempo real sobre Android. Ada es un lenguaje que ofrece soporte para aplicaciones con requerimientos temporales bajo la suposición de que la plataforma de ejecución proporciona las garantías necesarias en tiempos de respuesta. Para satisfacer estas garantías proponemos que las aplicaciones escritas en este lenguaje utilicen los mecanismos de aislamiento proporcionados por el sistema operativo Android/Linux, a través de los cuales es posible aislar uno o varios núcleos del procesador para ser usados exclusivamente por aplicaciones de tiempo real. Además, hemos estudiado los mecanismos que se encuentran disponibles en Android para compartir datos entre aplicaciones Ada con requisitos temporales y el resto de aplicaciones que se ejecutan en el mismo sistema.