bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimation of the Heat Stability of Hardened Cr-V Cast Irons
Authors: Koryagin Yu.D. , Il'ichev V.L.
Published: September 2016

The paper describes the structure, properties and heat stability of white cast irons containing 2.5 – 3.0 %C, 14 and 20 %Cr, 3 %V after the secondary hardness treatment (quenching from 1150 °C and double tempering at 560 °C). It is shown that after the secondary hardness treatment M23C6 carbides appear along with the M7C3 phase. Heat stability of the alloys is estimated according to GOST 19265-73 standard. The effect of the temperature and duration of holding at 520–620 °C on structural changes and softening of secondary hardness treated cast irons is considered in comparison with high-speed steel and cast irons of the same composition quenched for the maximum hardness (from 1050 °C). The processes occurring at higher temperatures and long holdings that are responsible for softening of secondary hardness treated cast irons are studied. It is shown that the alloys under consideration after the secondary hardness treatment achieve the hardness of HRC 60 and more, and are able of pertaining it when heated up to 540 °C for 20 hours. This allows using these alloys as wear-resistant materials in the said temperature range.
Influence of Steel Chemical Composition and Modes of the Thermomechanical Treatment on Mechanical Properties of a Hot Rolled Plate
Authors: Salganik V.M. , Chikishev D.N. , Pozhidaeva E.B.
Published: September 2016

A mathematical model for calculation of rolling pipe mechanical properties has been developed. The influence of alloying elements in steel by means of optimal process parameters of thermomechanical rolling was analyzed. There are two methods of mathematical modeling used in the study: the neural network modeling used to select the optimal chemical composition and the finite element analysis used to optimize the process parameters. Due to large availability, low cost and high accuracy of the results, these methods are considered to be the most promising ones. Two ways to reduce the cost of a hot-rolled plate from microalloyed steels have been developed. A complex of technological processing replacement was developed.
Evolution of Macro-Scale Plastic Flow Localization of Tri-Layered Stainless Steel - Low Carbon Steel - Stainless Steel Metal with Digital Image Correlation Method
Authors: Barannikova S.A. , Zuev Lev B. , Bochkareva A.V. , Lunev A.G. , Li Yu.V. , Shlyakhova Galina V.
Published: September 2016

Evolution of localized plastic deformation in tri-layered metal material casting consistng of the working part (layer) from austenitic stainless steel and bearing part from low-carbon steel was investigated. The pictures of localization of the plastic flow during the process of uniaxial tension were obtained by means of the digital image correlation method (DIC). Using optical microscopy methods, the changes in the fracture surface were investigated. The deformation diagrams were examined for deformed samples of tri-layered metal. These were found to show all the plastic flow stages: the linear, parabolic and pre-failure stages would occur for the respective values of the exponent n from the Lüdwik-Holomon equation. The analysis of the plastic flow stages and localized plastic deformation parameters was performed.
The Study of the Strained State of the Long-Length Aluminum Billet Obtained by a New Method - Multi-ECAP-Conform
Authors: Raab Georgy I. , Fakhretdinova E.I. , Valiev R.Z.
Published: September 2016

This paper presents the results of a computer and experimental study of a promising severe plastic deformation (SPD) technique, called Multi-ECAP-Conform (M-ECAP-C), for the fabrication of long-length nanostructured billets (wire rods) with an enhanced strength and electrical conductivity from the aluminum alloy EN-AW 6101 per one processing cycle. On the basis of the obtained results, a new rational geometry of the pressing channel for the M-ECAP-C process has been developed. The strained state of pilot samples of wire rods have been studied. Using the method of dividing grids shows the character of accumulation and the achieved level of deformation shear during the experimental treatment, and the average value of the shear deformation of the central region of the workpiece is 3.015. It was found that the error between the obtained values of the experimental method of grids, computer modeling and calculation is, respectively, 10 % and 17 %. The error between the experimental and computer modeling is not so important, so application of the computer modeling to estimate the strain state of the method of the Multi-ECAP-Conform is completely adequate.
The Mechanism of Water-Soluble Polymer Аdditives and Parameters of the Pulse Electrolysis Effect on the Size Distribution of the Electrolytic Copper Powder
Authors: Lipkin V.M. , Lipkin M.S. , Lachin V.I.
Published: September 2016

The principles of pulse electrolysis modes selection and their effect on the size distribution of the powder electrolytic copper in electrolyte with additions of water-soluble polymers, polyvinylpyrrolidone (PVP) and polyacrylamide (PAA) are considered in the paper. The research conducted with use of chronopotentiometry and potential transients as well as a simulation model of the electrocrystallisation process showed that the values of pulse duration were greater than the transient time of electroactive species and the pause duration equal to the linear part of potential transient was optimum to obtain a powder with a predominant fraction of nanoscale particles . PVP and PAA additives help to reduce the average particle size in the nanoscale fraction copper powder particles to 25-40 nm. Selected current pulse mode effect corresponds to the reduction of the emergence of new centers of crystallization probability and the adatoms on the surface of the cathode movement probability.
Technologies for the Manufacturing of Multi-Layered Hollow Structures by Superplastic Forming
Authors: Krioni N.K. , Mingazhev A.D. , Kuzeev I.R.
Published: September 2016

Hollow multilayered structures are increasingly used in various fields of engineering and technology. One of the most important applications is шт aircraft engine construction and power-plant engineering. In recent years, the methods of superplastic forming have started to be used to obtain hollow parts specified for different areas. However, despite significant advances in this field, these technologies have several drawbacks, leading to the emergence of technological defects, particularly those associated with the the effect of Baushinger. In this regard, this article discusses the development and study of a technology for production of multilayer hollow constructions by superplastic forming, in particular, degradation process of adhesive bonds in areas, forming cavities in a constructional workpiece. It is shown that the use of more delicate effects to create the breaking away of the load enables the reduction of process defects in the part.
Development and Implementation of Energy Efficient Burners at Power Stations
Authors: Dubrovsky V.A. , Zubova M.V. , Potylitsyn M.U.
Published: September 2016

The article deals with the coal thermal treatment for boiler firing with minimal consumption of fuel oil. The estimation of commercial effectiveness of innovation projects using this technology proves its high investment attractiveness.
Improvement of Liquid Organic Fuel Oils Operational Characteristics with Additives
Authors: Zvereva E.R. , Zueva O.S. , Khabibullina R.V.
Published: September 2016

The results of experimental studies into the viscosity of heavy fuel oils mixed with a liquid additive Diproksamin-157 and a solid additive based on dehydrated carbonate water treatment sludge with a concentration of 0.5 wt. % are presented. Experimentally it has been found out that the viscosity characteristics of fuel oil at the addition of Diproksamin-157 showed nearly 20 % improvement, and at addition the carbonate slurry –7 – 10% improvement. In the case of water-fuel emulsion comprising carbon nanotubes the improvement of the rheology oil characteristics to 10 – 25% by introduction of carbon nanotubes water suspension containing 0.82 wt. % into fuel has been observed. However this result at the moment has only basic value as it is not economically reasonable to use carbon nanotubes in such concentration.
Low-Sulfur Fuel and Oil Production
Authors: Kuimov D.N. , Minkin M.S. , Lukyanov A.D.
Published: September 2016

Problems of transforming heavy crude high-sulfur oil into low-sulfur fuels and oils become increasingly urgent for oil refineries. The main reason for that is depletion of low-sulfur oil-fields and following rise of heavy crude oil share in world's oil production. Desulfurization of oil and petroleum residues is performed by breaking down or extraction of sulfur and sulfur compounds with catalyst and chemical additives which leads to considerable rise in price of refinery. Desulfurization technology proposed in the following research involves simultaneous use of the acoustic and hydrodynamical cavitation for breaking down long molecular connections. Oil refinery was performed in the electromechanical vortex layer activator which intensified mechanoactivation processes by intensive movement of ferromagnetic elements in the external magnetic field.
Optimization of Oil Particles Separation Disperser Parameters
Authors: Deeva V.S. , Slobodyan S.М. , Teterin V.S.
Published: September 2016

Retaining structure of homogeneous fluid and granular stream is one of the main criteria for technological process assuring the high quality outcome in many industries, including mechanical engineering and oil & gas industry. For example, in oil and gas industry during the pipeline transportation of oils there is a strong trend for cluster aggregation, and particle coarsening and entanglement. Dehomogenization of particle stream results in reverse dynamics of the stream. The importance of prevention and minimization of small particles coalescence by separating the oil stream leads to the need of improving the properties of the dispersers to boost their efficiency. Our paper investigates the operating principle of the disperser for separating particles (separator), which is designed by the authors. We have considered a particle stream of dispersed structure. We have obtained the conformity with the stability of the disperser operation. To yield the results we use the extremum problems for differential equations. This approach provides strong evidence that there are optimum parameters of the dispersers, which result in better stability of the particle stream.
Modern Technological Possibilities of the Environmental Safety of Food Production
Authors: Kretova Yu.I. , Merenkova S.P. , Lukin A.A.
Published: September 2016

High susceptibility of barley to pathogenic microorganisms leads to decrease in quality. Under the influence of metabolic products of microorganisms biochemical processes occur in grain leading to changes in the protein-carbohydrate balance, the emergence of a large number of low molecular weight proteins and increased acidity. During the long process of molding grain can form toxic substances such as aflatoxins, citrinin, ochratoxin, zearalenone. Mycotoxins belong to a group of natural toxic chemicals and constitute a serious risk to human health and animals because of their toxicogenic, carcinogenic, mutagenic effects. This grain mass can not be used in the production of malt and beer. The level of infestation of grain by microorganisms depends on many factors. Conditions of processing of grain after harvest is one of the main factors, therefore, timely technological treatment of barley grain is important. Traditional methods of grain processing do not always meet the safety requirements, some methods are energy intensive and have a very limited scope. The effective method of reducing the mycelial infestation − method of electrophysical influence, in particular, microwave heating.
New Method for Determining the Electron Streams in the Metals from the Measured Flows of Scattered Primary Radiation
Authors: Kosianov P.M.
Published: September 2016

The paper examines the results of theoretical and experimental studies of different interaction of ionizing emission photons with substances, in particular, the photo effect and the Compton scattering of these photons. The paper substantiates a new method of determining the recoil electrons number - the photoelectrons number ratio. The results of certain measurements are presented. The analysis of the results showed that there are noticeable divergences between the theoretical calculations and the experimental data.
Research the Properties of Temperature High-Coercivity Permanent Magnets NdFeB
Authors: Ismagilov F. , Vavilov V. , Farrakhov D.
Published: September 2016

The article addresses the issue of improving the accuracy of power electromechanical systems design. The performance of power electromechanical systems relies on the performance of permanent magnets used, which is nonlinearly dependent on temperature. It is shown that the calculation error introduced by this nonlinearity cannot be described accurately enough with one equation. It is also shown that the performance of thermally unstable magnets can degrade abruptly at a certain temperature, which causes additional and unpredictable decrease in electromechanical system’s performance.
Corrosion-Resistance of MAO-Coatings on Al-Si Alloys
Authors: Dudareva N.Y. , Abramova M.M. , Kalschikov R.V.
Published: September 2016

The results of the experimental study of the influence of micro-arc oxidation (MAO) on the corrosion resistance of aluminum alloy samples AK12D are presented in this paper. The description of the research methodology, including the formation of the hardened layer on the surface of laboratory samples by MAO under various process conditions and the study of their corrosion resistance are given. The studies were conducted in accordance with the experimental design theory for fractional factorial experiment 23-1. The MAO process was carried out using an alkaline electrolyte. MDO process factors were chosen according to an electrolyte concentration of the components (caustic potash - KOH and water glass - Na2SiO3) and electrical parameters of the process determined by the capacitors capacitance. In addition to corrosion resistance of the samples, the thickness, porosity, and microhardness of MAO layer were determined. Regression equations and conclusions about the degree of influence of modes of micro-arc oxidation on the corrosion resistance of the samples were compiled on the basis of the data obtained. The results showed that the MAO process regimes have a significant effect on the corrosion resistance of the samples. Regression equations describing the effect of the thickness and porosity of the surface on the corrosion rate are derived. It has been found that the greatest influence on the corrosion resistance renders the mean value of porosity. With an increase of this parameter there is an increase in the corrosion resistance of the coating. To account for this effect, it has been suggested that the corrosion resistance of the MAO layer should not correlate with the porosity but with the absolute volume occupied by the pores in the coating. The study was conducted to investigate the prospects for the use of the MAO method for improving the corrosion properties of parts and details made of Al-Si aluminum alloys.
Study of Thermal Resistance and Mechanical Properties of Thin Sheets of Low-Alloyed Aluminum Al-Cu-Mn and Al-Mg-Si Alloys
Authors: Demyanenko E.G. , Popov I.P.
Published: September 2016

The paper investigates a variety of properties of thin aluminum sheets fabricated using physical action of pulsed magnetic fields and weak pulsed current. The possibility of using thermal resistant aluminum alloys parts in aircraft manufacturing, including ones made by forming processes which require sufficiently high plasticity of initial sheets, is widely discussed. Two possible technological options have been tested for manufacturing sheet samples of Al-Cu-Mn and Al-Mg-Si alloys. A set of properties has been investigated (thermal resistance, mechanical properties, specific electrical conductivity, macrostructure of weldability zones, corrosion resistance of alloy samples. Casted workpieces were thermo-mechanically treated by heating and upsetting to 50 – 55 % with consequent hardening and aging. After that workpieces were subjected to multi-cycle rolling up to 0.3x10-3 m. The achieved results demonstrate that after 400 hours of exposure to 250°C, the thermal resistant parameters by tensile strength are higher after the exposure to weak pulsed currents than after the exposure to pulsed magnetic fields. Maximal thermal resistant parameters by tensile strength and maximal electrical conductivity was achieved in 01327+Sc (Al-Mg-Si) alloy. The mechanical properties, corrosion resistance and Erichsen formability parameters were also determined.
Structure Formation and Phase Composition of Sulfur-Bitumen Systems
Authors: Gladkikh Vitaliy , Korolev Evgeniy , Husid Dmitrij
Published: September 2016

Nowadays, modification of the bitumen by sulfur is considered as an effective way to enhance the properties of materials for road construction. By means of using the sulfur we eliminate the need to reconstruct existing production facilities for asphalt concrete. There is a plenty of research had already been performed for investigation of the sulfur-extended asphalt. Still, formation of new compounds in sulfur-bitumen systems depends on many factors, including mixture and thermal conditions. In the present work we have carried out both experimental and theoretical examination of the specific sulfur-bitumen binder made of grade 60/90 petroleum bitumen and technical sulfur at temperatures that are typical for ordinary asphalt concrete technology. The obtained results indicate that there is no noticeable formation of new chemical products in sulfur-bitumen melts at temperatures below 145 °C. Sulfur is partially dissolved in bitumen during the technological operations; the limiting concentration of dissolved sulfur is near 10%. Later in the course of cooling, the crystallization of the sulfur takes place, accompanied with formation of a separate solid phase.
Recycling Waste Wood of Construction
Authors: Grigorieva Larisa , Oleinik Pavel
Published: September 2016

The article considers contemporary methods and especially recycling of wood waste. The volume of wood waste is constantly growing due to the increase in the number of buildings subject to demolition or dismantling, reconstruction and repair works. The article contains the main requirements to the raw material derived from waste. Advantages of products made from wood-polymer composite materials on physic mechanical parameters. The comparative characteristic of cost for the production of wood-polymer plastic. It is noted that production made from wood polymer composite materials has unlimited product range, including boards, various profiled molded and moulded details with complicated shape (the board for the floor, skirting board, baguette, etc).
Fire and Explosion Protection of High-Rise Buildings by Means of Plaster Compositions
Authors: Gravit Marina , Mikhailov Egor , Svintsov Stepan , Kolobzarov Aleksey , Popovych Ivanna
Published: September 2016

The article describes the aspects of fire protection of high-rise buildings. Various methods of protection of unique buildings from fire and explosion in the world practice were considered. For example, using the innovative fire-resistant materials on load-bearing structures, their characteristics and rationing, progressive collapse. The comparative analysis of various types of fire-resistant plaster by such parameters as the chemical composition, fire resistance, durability, density, thickness of the layer was made. Perspectives of development of fireproof plaster compositions were projected.
Diagram of Non-Linear Straining of Carbon-Fiber Reinforced Concrete at Static Effect
Authors: Plevkov Vasiliy , Belov Vyacheslav , Baldin Igor , Nevskiy Andrey , Veselov Anatoliy , Serov Evgeniy
Published: September 2016

The article reflects the results of experimental studies of carbon-fiber reinforced concrete under compression and tension. Qualitative change of concrete strength and stress-strain properties at its dispersed reinforcement with carbon fibers is fixed. As a result of the statistic processing of experimental data, analytical dependencies for determination of carbon-fiber reinforced concrete main strength and stress-strain characteristics under compression and tension are suggested. Calculation diagram of non-linear straining of carbon-fiber reinforced concrete at static effect is presented.
Complex-Action Reagent for Oil-Infield and Oil-Trunk Pipelines
Authors: Nelyubov Dmitry , Shabarov Alexander , Podorozhnikov Sergey
Published: September 2016

Development results of an oil field reagent TNCHS-15.0 are presented, this is a solution of non-ionic surfactants composition, that can prevent asphaltene-resin-paraffin precipitation of oil and lower viscosity of oil dispersed systems during transport via pipeline. Effectiveness of developed reagent is proved by the results of laboratory researches in LLC «RN-UfaNIPIneft» with recommendation to conduct field tests on Ust-Tegusskoe field of LLC «RN-Uvatneftegaz». Viscosity reduction at temperatures, typical for oil transportation, is 55% and effectiveness of asphaltene-resin-paraffin precipitation inhibiting is 62%.
Structure of Polymer Composites on Basis of Epoxy Resin and Organic and Inorganic Dispersed Industrial Wastes
Authors: Galeev Ruslan Razinovich , Maisuradze Natalya Vyacheslavovna , Abdrakhmanova Lyailya Abdullovna
Published: September 2016

he paper presents the influence of the conditions of combining of the epoxy binders and particulate filler on the formation of submolecular structure of the composites. The optimum concentrations of filler among industrial waste in the composition content has been determined and the dependence of the formation of the structure of the following technological parameters such as filler concentration, order of components combining (epoxy resin, hardener and filler), solidification modes of the composition has been identified. Microphotographs of the structure and interpretation of the connection of the properties of the composites and their structure are presented below.
Effective Sediment Treatment of Urban Sewage by Microwave Radiation
Authors: Vialkova Elena , Zemlyanova Marina , Pesheva Anna
Published: September 2016

In this paper, we propose a method of treating wastewater and sludge by microwave radiation. Many Russian scientists are studying microwave effect on the properties of water and sladge and they are solving the practical application of microwave technology in the treatment of wastewater and sludge. Research carried out at the department “Water supply and sanitation”, Tyumen State University of Architecture and Civil Engineering (Russia), confirm changing properties of water and sediments. So too studies confirmed the economic feasibility of the use of microwave radiation for treatment plants having small capacity.
Increasing Hot Rolling Mass of Steel Sheet Products
Authors: Artiukh Viktor , Mazur Vladlen , Prakash Raghu V.
Published: September 2016

The article exposes contemporary materials and structures for metallurgy. Feasible increase of dynamic forces on the rolling machinery during rolling of billets with masses up to 20 t (Stand No.1 of CWM 1700 HR, «U.S. Steel Košice», Košice, Slovakia, and PJSC «Illich MMPP», Mariupol, Ukraine) is discussed. It is proved that weight of billet, velocities of metal delivery to working rolls and rolling significantly influence the dynamic loads during metal biting. The technical solutions are suggested which would allow the steady rolling process of billets with masses up to 20 t and prevent accidental failures of frame parts, chocks and main lines.
Self-Organization Processes in Silicate and Cement Construction Materials
Authors: Sidorenko Yulia V. , Korenkova Sofia F.
Published: September 2016

Innovative materials and structures are analyzed in this paper. On the basis of provisions of the systems analysis the principles and approaches to modeling of processes of contact and condensation curing of silicate materials are developed. The mechanism of contact and condensation process on macro - and mesolevels of system is presented. There are provisions of synergetic at its base: formation of an infinite cluster of a framework of a raw from the power links connected by a contact condensation crossing point as a result of redistribution of an unstable phase calcium-silicate knitting between sources and drains of structure-forming elements. Theoretical modeling of intergrain condensation at the base of which there are submodels of the squeezed deposit and a capillary porous body is executed. The nanosized filler has a polyfunctional influence on the structure and properties of calcium-silicate and cement materials, takes part in the formation of new chemical compounds and the structure of pore walls.
Eco-Friendly Polymer Construction Materials
Authors: Gerasimova Vera , Zotikova Olga
Published: September 2016

This article addresses contemporary construction polymer elements found useful in civil engineering and construction in Russia due to their high technical and economical efficiency. Advantages and drawbacks of the polymer materials are reviewed. This work in no way claims a fullness of reviewing all the issues of using polymers in construction, but it nevertheless enables to provide a general insight into the problems to be solved in the field of future production and use of environmentally safe polymer materials for construction applications. One of the substantial goals of the applied research is to design rather durable, non-toxic and fire-resistant construction materials intended for construction of residential and public buildings. Readers can get an overview about ecological problems linked to the production and application of the polymers in construction field.
Nano Filled Façade Plasters to Increase Durability of Building and Structures
Authors: Perlova Elena , Platonova Maria , Bondarenko Evgeny , Togo Issa , Tereshchenko Alexander , Fikfak Alenka
Published: September 2016

Innovative materials and structures are analyzed in this paper. The quality indicators of the wet front systems could be improved by possible expanding the range of mineral fillers due to the use of raw materials nanotehnological carbonate.This work is dedicated to use of nanofilled compositions for plastering in order to expand the competitiveness of Russian producers. It presents an experimental method of determining strength of the separation of the sample solution from the hardened base (brick or concrete). Educed the effect of the sludge and the PCC on the plasters composition.
Influence of Fillers on Polyvinyl Chloride Materials Thermal Resistance
Authors: Nizamov Rashit , Abdrakhmanova Lyailya Abdullovna
Published: September 2016

Innovative materials and structures are analyzed in this paper. Multicomponent formulation of polyvinyl chloride materials containing various functional additives requires assessment of their influence on polymer stability while processing and operating. According to the nature, particulate fillers widely used in plasticized and liquid compositions based on polyvinyl chloride may have different impact on thermal resistance of materials. This paper presents the study of organic and nonorganic dispersed waist as filler in polyvinyl chloride formulation and determines key parameters of their influence on thermal resistance of composition. Polyvinyl chloride stabilization course by means of polyfunctional fillers-modifiers in different mechanisms, such as: chemical stabilization – chloride hydride acceptance, replacement of chlorine labile atom in polymer macromolecule, adjoining conjugated defective ethylenic bonds, recombination macroradicals and physical stabilization – chloride hydride sorbing, reduction of mechanical destruction by oiling, etc. have been considered. Contribution into stabilization course in various mechanisms depending on chemical nature, dispersion rate and mineral content of fillers is evaluated.
Heat Liberation of Barium Cements as a Background of their Application in Mass Concrete Structures
Authors: Barabanshchikov Yury , Belkina Tatiana , Muratova Anna , Bieliatynskyi Andrii
Published: September 2016

The article deals with heat liberation of barium cements, which influences the crack formation in mass concrete structures. The results of heat release and physical testing of barium cements with a different content of BaO are presented in this paper. The strength of cement and its setting time will decrease significantly, if the content of BaO in clinker is high (about 47%). This cement is characterized by a low water requirement and heat liberation. Properties of cement with a low content of barium oxide (5.5%) are close to the properties of the standard Portland cement. In this case heat liberation is low in the initial period of hardening, but at the later stage it exceeds the exotherm of a reference sample. A small amount of BaO in cement clinker reduces the exothermic effect and increases the thermal crack resistance of concrete.
Basic Concepts of Solar-to-Chemical Energy Conversion by Oxide Semiconductors
Authors: Alim Mohammad A. , Bak Tadeusz
Published: September 2016

The purpose of this work is to consider the basic concepts on the present state of understanding of photocatalytic energy conversion using oxide semiconductors. This work also considers the approaches in derivation of theoretical models that allow explanation of the effect of properties on the performance of oxide-based photocatalysts in photocatalytic water oxidation. In this work we show that the performance of photocatalytic systems must be considered in terms of a range of the key performance-related properties (KPPs) that, in addition to the band gap, include the concentration of surface active sites, charge transport and Fermi level. Taking into account that all these KPPs are related to defect disorder, defect engineering may be applied in processing oxide semiconductors with optimal properties that are required to exhibit maximised performance in solar-to-chemical energy conversion.
Analytical Calculation of Resistance to Burst of Single Jersey Underlying Two Synthetic Materials Used in Furniture Industry
Authors: Lengyel Bianca , Cernescu Anghel , Nes Cristian Sorin
Published: September 2016

Synthetic leather materials, that have single jersey in their structures, are widely used both for the seat covers of cars and in the case of seats for furniture used in everyday life. To develop constructive and ingenious solutions that increase the durability of these materials in time, it is necessary to know all the requests that these materials have fulfil. In this paper we proposed an analytic study of two synthetic leather materials in terms of resistance to burst of the knits underlying their composite structure.
A Study of Mode III Fracture Toughness in Young and Mature Concrete with Fly Ash Additive
Authors: Golewski Grzegorz Ludwik , Sadowski Tomasz
Published: September 2016

A description of processes of formation and propagation of cracks in material requires the knowledge of all fracture mechanics parameters, i.e.: KIc, KIIcand KIIIc. In this study a new testing method and estimation of the fracture toughness in Mode III (antiplane shear) of concretes containing: 0, 20 and 30% volume content of the class F fly ash (FA) was proposed. Fracture toughness tests were performed on axial torsion machine MTS 809 Axial/Torsional Test System. The studies examined effect of FA additive on the parameter KIIIc. In order to determine the fracture toughness KIIIca special device was made. Experimental investigation under third mode fracture was carried out both in young and mature concrete composites (after: 3, 7, 28, 90, 180 and 365 days). 20% addition of FA as well as a 30% addition of FA causes a reduction in fracture toughness of young concrete. After 28 days of couring a significant increase of the KIIIc was noticed in composites with a 20% additive of FA while concrete mixtures with a higher additive of FA still had lower analyzed fracture mechanics parameter.
Thermal Analysis to Optimize and Control the Cast Iron Solidification Process
Authors: Riposan Iulian , Stefan Ion , Firican Ciprian , Stan Stelian
Published: September 2016

The cooling curve and its derivatives display patterns that can be used to predict the characteristics of a cast iron. The effects of melting, superheating and holding in an acid lined coreless induction furnace were explored, as they affect the role of preconditioning and / or inoculation to restore solidification with low eutectic undercooling. Increased chill (iron carbides amount) in the experimental irons correlates well with certain thermal analysis parameters, such as the degree of eutectic undercooling. Preconditioning of the molten base iron before tapping led to improved solidification parameters in both untreated and inoculated irons as measured by the most significant thermal analysis cooling curve events. A double treatment incorporating preconditioning with inoculation improved the thermal analysis parameters, and consequently, the quality of the cast iron. If standard Ca-FeSi alloys do not have sufficient inoculation potential, the addition of the inoculant enhancing alloy (S, O and oxy-sulphides forming elements) will greatly enhance inoculation, well illustrated by changes to the thermal analysis parameters. A newly defined Inoculation Specific Factor [inoculation effect / inoculant consumption which led to that beneficial effect ratio] of different alloys is illustrated by thermal analysis, with good correlation with microstructural characteristics.
Heat Transfer Process in Jet Turbine Blade with Functionally Graded Thermal Barrier Coating
Authors: Sadowski Tomasz , Pietras Daniel
Published: September 2016

In the jet engine the temperature of exhaust gases should be as high as possible, from the point of view of its efficiency. The value of this temperature is limited by toughness of the turbine blades material. Superalloy Inconel 625, which is commonly used in aerospace industry, indicates 13% less yield point in 800OC than in 25OC. The temperature of exhaust gases can reach 1500OC. The blade material has to be protected due to this fact. The one possibility of turbine blade protection is using of thermal barriers coatings (TBC). The coating has a very low thermal conductivity and therefore it protects against the thermal shock failure of the substrate material. The TBC can be manufactured as: 1) monocrystalline, 2) layered structures (e.g. [1-3]) or 3) as a functionally graded material (e.g. [4-7]). The differences between the properties of blade material and TBC can lead to significant increase of the high shear stresses in the substrate-TBC interface.In this paper numerical analyses of cooled turbine blade with various kinds of functionally graded thermal coatings were performed. The main aim was to find the optimal material properties distribution of the functionally graded TBC to avoid damage initiation and growth between TBC and substrate. In the calculations the effect of temperature on material properties both mechanical and thermal was taken into consideration.
Optimization of Synthetic Slag Additions Used in Continuous Casting of Steel
Authors: Ardelean Marius , Lăscuțoni Alina , Ardelean Erika , Socalici Ana Virginia
Published: September 2016

The appropriate use and in adequate quantities of synthetic slags in continuous casting process (insulating coating powder in tundish and respectively lubricant molding powder in crystallizer) gives a good quality of continuous castings products. The paper presents two methods of determining the necessary of slags: using dispersion analysis software Minitab.v17 and optimization of heat transfer in tundish, depending on powder coating thickness, performed with a program made in Mathcad14 and respectively optimization of the molding powder thickness, using an own simulation program. Both methods are based on the properties of steel grade which is casted (in particular the liquidus temperature of the steel) and they can be adapted to the specifics of the continuous steel casting machines.
Preliminary Tests for Precious Metals Recovery from Sideritic Waste
Authors: Cânda Letiția , Ardelean Erika , Ardelean Marius , Strugariu Laura
Published: September 2016

Waste deposited in ponds can also contain precious metals, as trace elements. Preliminary studies have shown, by chemical analysis, the presence of gold and silver in waste steel. This paper presents some preliminary aspects of experimental work related to gold recovery opportunities from sideritic waste, Teliuc type - stored as a pond and future directions in research. There were two distinct phases considered: gravimetric concentration and removal of three layers from the experimental material, respectively, the treatment of the concentrate with “aqua regia”.
Mechanical Characteristics Alteration of a Steel Used in Water Turbine Blades
Authors: Coman Răzvan , Ciocoiu Robert , Diniță Alin , Ciucă Ion
Published: September 2016

A water turbine blade was investigated after it was discarded. First general macroscopic observations were performed on the turbine blade surface and then chemical composition of the steel was determined by arc spark optical emission spectroscopy. The study aimed to observe if the mechanical properties of the steel changed by a significant amount when compared with literature data. Tensile and impact tests were performed. The samples were obtained from transverse sections from the blade.
Research on Composite Materials Used for Brake Shoes Manufacture
Authors: Popa Erika , Pascu Liviu , Socalici Ana Virginia , Ardelean Marius
Published: September 2016

The paper relates laboratory experiments in order to obtain a composite material used for brake shoe manufacture. Regarding the testing materials were processed 38 samples. The percentage and composition of materials are: 15-45% novolac, 1,5-10% hexametyltetramin, 0-8% sulfur, 0-15% carbon fiber, 0-20% graphite, 0-25% aluminum, 15-28% brass and 0-40% rubber. The evolution of tribological and temperature parameters were analyzed in the contact zone tribological testing disk - split pin method. The composite material has the role to replace the classic material (cast iron) used in brake shoes composition in order to reduce the noise caused by rolling stock.
Researches Regarding the Influence of Vacuum Parameters on the Efficiency of Gas Removal from the Liquid Steel
Authors: Ardelean Erika , Hepuț Teodor , Vătășescu Mihail , Crișan Eugen
Published: September 2016

The presence of gas in steel is a problem in terms of quality, by the way how is influenced steels mechanical and technological characteristics.Current steel making technology allows inclusion of gas content at relatively low value, but under current conditions, it places a great emphasis on the purity of the steel and the superior mechanical and technological properties, secondary treatment is required (ladle metallurgy) and, if possible, even the treatment of liquid steel in vacuum installations. The paper presents the influence of the main parameters of vacuum treatment (treatment duration, high vacuum period) and thermic parameters of steel (input and output temperature of the steel in installation) relative to hydrogen and nitrogen contents from steel for processing on automatic machines. Correlations obtained are presented in Excel and Matlab both the analytical and graphical form.
Numerical and Experimental Analysis of Foreign Objects Impact into the Surface with TBC Coating
Authors: Sadowski Tomasz , Golewski Przemysław
Published: September 2016

While the plane is maneuvering before start or landing, some solid particles (e.g. sand, dust, soil) can be sucked into an engine with the air. Their vast majority is stopped on the compressor blades, but the smaller ones are able to get into a hot part of the engine and cause erosion. Erosion is widely recognized as the second mechanism, after corrosion that reduces the TBC coating thickness. In many cases, erosion can completely remove it. Furthermore, TBC coatings are more susceptible to erosion due to their porous structure than full dense ceramic materials.
In order to investigate the phenomenon of particles impact with diameter of 4mm, the pneumatic driven laboratory work station was built. The work station has an adjustable pressure, so that the foreign object may possess different kinetic energies. The pressure can be read on a digital pressure gauge and the shot release is done electrically. In addition, the work station has a universal cross table that provides precise positioning of the sample so as to be able to perform a dozen or so impacts in predetermined distance intervals. However, the most important component is the velocity measurement system which is used to determine the impact energy.
The paper presents the results of 11 impacts made with different energies. The effect of complete destruction of the ceramic layer as well as indents without visible damage was achieved. Numerical simulations allowed to define the zones of stress influence of the individual indents. The brittle cracking model in Abaqus allowed the virtual representation of damage due to impact load.
Numerical and Experimental Studies of Fluid Flow and Heat Transfer in a Model Experiment for Hydrothermal Growth
Authors: Ursu Daniel , Negrila Radu , Popescu Alexandra , Grozescu Ioan , Vizman Daniel
Published: September 2016

Understanding of the natural convection flow in hydrothermal autoclaves is essential for the control of the growth rate and the quality of the grown crystals. This paper presents an analysis of the natural convection fluid flow and heat transfer and show the comparison between simulation and experimental results for the experimental model in a small size autoclaves, fill with water. A numerical model based on finite volume method has been developed to simulate the heat transfer and fluid convection in the vessel. Results show that the flow will strongly affect the temperature distribution. It can be observed that in the upper region the liquid flows up in the middle of the vessel and flows down in lateral parts near the walls. The temperature difference between experimental and simulation results is less than 1 °C in the upper part and between 2 and 3 °C in the bottom part. Velocity measurements show a good qualitative agreement between simulation and experimental results. The value of the z-component of velocity along the symmetry axis slightly increase with the increases of temperature difference ΔT .
Numerical Model of Thermal Field Developed in Fe67Cr4Mo4Ga4P12B5C4 Bulk Amorphous Alloy Processing
Authors: Radu Bogdan , Buzdugan Dragoş , Codrean Cosmin , Şerban Viorel Aurel , Vișan George
Published: September 2016

Metallic amorphous materials were developed during 80’s as new materials, with very interesting industrial properties (heat conductivity, magnetic properties, fusion temperature, corrosion resistance, etc.). Technology to obtain these materials, based on very rapid cooling of a melted alloy with glass forming ability, has limitations for the dimensions of the products that can be obtained with amorphous structure (thickness has to be very thin), which can be overpassed by development of bulk amorphous alloys with high glass forming ability and good control of the cooling speed. Numerical modeling of thermal field during ultra-high cooling, developed in researches presented in this paper, allows researchers to estimate the results of applying in reality certain cooling conditions. This model will help developers of bulk amorphous alloys in checking if are ensured conditions to obtain an amorphous alloy with fewer experimental tests, less time and low expenses.
The Influence of Cooling Rate and Equivalent Carbon on the Chill Tendency and Cooling Curves Parameters in Uninoculated and Inoculated Grey Cast Iron
Authors: Panciu Elena , Anca Denisa Elena , Chisamera Mihai
Published: September 2016

The main objectiv of this experimental research is a comparative analysis of the changes caused by varying both of cooling rate and carbon equivalent content on depth of chill tendency and cooling curves parameters of grey cast irons.
Numerical Modeling of Thermal Field Distribution during Friction Stir Welding (FSW) of Dissimilar Materials
Authors: Radu Bogdan , Codrean Cosmin , Cojocaru Radu , Ciucă Cristian
Published: September 2016

Friction Stir Welding (FSW) is an innovative solid state welding process, relatively new in industry, which allow welding of two or more materials which have very different properties, particularly thermal properties as fusion temperature, thermal expansion coefficient, specific heat and thermal conduction and have a predisposition to form intermetallic brittle phases, neither one of the components to be weld reach to the melting point. Being a solid state welding process temperature field is very important for the quality of the welded joint, and a lot of researches focused on this topic. This paper presents some results in modeling and estimation of thermal field developed during FSW of dissimilar joints, using Finite Element Analysis. Numerical modeling of thermal field allows engineers to predict, in advance, the evolution of temperature and to estimate the behavior of the welded materials during the welding process. This will reduce significantly the time and number of experiments that have to be carried out, in the process of establishing a good FSW technology, as well as reducing significantly the cost of the tests.
Influence of the Graphitisation Degree of Carbon Nano Fibres Serving as Support Material for Noble Metal Electro Catalysts on the Performance of PEM Fuel Cells
Authors: Rost Ulrich , Muntean Roxana , Podleschny Pit , Marginean Gabriela , Brodmann Michael , Şerban Viorel Aurel
Published: September 2016

In this experimental work polymer electrolyte membrane fuel cell (PEMFC) electrodes are analysed, which are prepared by the use of two sorts of carbon nano fibres (CNF) serving as support material for platinum nano particles. Those CNFs, which are heat treated subsequently to their production, have a higher graphitisation degree than fibres as produced. The improved graphitisation degree leads to higher electrical conductivity, which is favourably for the use in PEMFC electrodes. Samples have been analysed, in order to determine graphitisation degree, electrical conductivity, as well as morphology and loading of the prepared electro catalyst. Membrane electrode assemblies manufactured from prepared electrodes are analysed in-situ in a PEM fuel cell test environment. It has been determined that power output for samples containing CNFs with higher graphitisation degree is increased by about 13.5 %.
Numerical Simulation of Friction Stir Welding (FSW) Process Based on ABAQUS Environment
Authors: Iordache Daniela Monica , Bădulescu Claudiu , Nitu Eduard Laurentiu , Iacomi Doina
Published: September 2016

. Simulation of the FSW process is a complex issue, as it implies interactions between thermal and mechanical phenomena and the quality of the welding depends on many factors. In order to reduce the time of the experimental tests, which can be long and expensive, numerical simulation of the FSW process has been tried during the last ten years. However, there still remain aspects that cannot be completely simulated.
In this paper the authors present the steps of the numerical simulation using the finite elements method, in order to evaluate the boundary conditions of the model and the geometry of the tools by using the Arbitrary Lagrangian Eulerian (ALE) adaptive mesh controls.