bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modeling the deformation behavior of polymer sandwich structures with inhomogeneous core
Authors: Takacs Laszlo , Szabó Ferenc 
Published: August 2020

Abstract
Polymer sandwich structures become widely used in the transportation industry due to their high bending stiffness and strength combined with low weight. In the conceptual design phase, it is essential to model the mechanical behavior of the sandwich properly in full-vehicle scale in order to analyze different design variants effectively. In this paper, a finite element modeling method is shown. The method is introduced on a sandwich structure with glass fiber reinforced, vinyl-ester matrix composite face-sheets and a PET foam as core material with an inhomogeneous structure. To model the sandwich panel with layered shells, where the core material is a single layer, equivalent stiffness constants of the inhomogeneous core are needed. To determine these constants, a detailed finite element model was created and virtual tensile and shear tests were performed. On the other hand, an analytical method was also shown. By applying the Voigt- and Reuss-rule on the inhomogeneous core, the needed stiffness constants can also be determined properly. Results of the two methods were compared and they showed a good correlation. Validation of the model was performed via comparing the results of the 4-point bending experimental tests and the simulation results.
Characterization of short fiber-reinforced polylactic acid composites produced with Fused Filament Fabrication (FFF)
Authors: Csenge Tóth , Norbert Kovács Krisztián 
Published: August 2020

Abstract
The interdisciplinary expansion of additive manufacturing (AM) technologies resulted in an increasing demand for high-performance materials for engineering applications. In order to enhance the mechanical properties of printed products, short fiber composites are of great interest recently. In this study, the development of short fiber-reinforced composite materials is performed along with the mechanical characterization of the samples produced by fused filament fabrication (FFF) technology.
Comparison of CT and metallographic method for evaluation of microporosities of dye cast aluminum parts
Authors: Bubonyi Tamás , Barkóczy Péter , Gácsi Zoltán 
Published: August 2020

Abstract
Nowdays, the different material characterisation and testing methods are constantly evolving. With modern techniques, we have the ability to take a look inside the product without sample cutting, with modern CT systems. The modern techniques with their development become closer and closer to industrial applications. However, the testing protocols are sometimes 1 or 2 steps behind. This is mostly due to the cost or the complexness of the new testing methods. In this study we would like to take a quick look on the current standard industrial testing of porosities and microcracks and compare them with computer tomograph assisted testing.
On the necessity of domestic research on nuclear materials science
Authors: Trampus Peter 
Published: August 2020

Abstract
Globally, systematic research is going on to better understand the operation induced degradation effects of reactor structural materials and to enhance the effectiveness of their in-service monitoring. In Hungary, there are four reactor units in operation and two new ones are soon to be built. Some of the construction features of the new units differ from that of the operating ones. In order to be prepared in time for efficiently managing materials science related questions, it is necessary to establish a coordinated research program utilizing the capabilities of domestic research institutions. This paper describes the major elements of this potential program. Implementation of the program can assist ageing management activities of the operating units.
Preparation and characterization of poly(lactic acid)/boehmite alumina composites for additive manufacturing
Authors: Lendvai L , Fekete I 
Published: August 2020

Abstract
The purpose of this work is to investigate the suitability of boehmite alumina (BA) reinforced poly(lactic acid) (PLA) for additive manufacturing with the fused filament fabrication method. PLA filaments with 0-10 wt.% BA content were produced via melt compounding using a twin-screw extruder. Dumbbell-shaped and prismatic specimens were manufactured then by feeding the prepared filaments into a desktop 3D printer. Mechanical, morphological and melt flow properties of the developed samples were determined. The addition of BA decreased the melt flow rate of PLA, however not so much that it would have hindered its suitability for 3D printing. With increasing BA content both the strength and the stiffness of the samples increased slightly at constant deformability and toughness. Scanning electron microscopic images revealed a homogenous dispersion of BA particles within the PLA matrix, although remaining agglomerates were also observed.
Advanced method for measuring slurry surface tension
Authors: Dzhambulatov R , Savvin V , Bataev D , Khasanov A , Uspazhiev R , Khasbulatova Z , Bagov A 
Published: August 2020

Abstract
The work is devoted to a method that makes it possible to level the influence of sedimentation on the surface tension of slurry. To do so the methods for measuring surface tension are used, where the sedimentation process is multidirectional relative to the surface under study. An analysis of the results shows that the proposed method can virtually eliminate the influence of sedimentation on the surface tension of dispersed systems with low kinetic stability. Using the proposed method, the concentration dependence of the surface tension of aqueous slurries of bentonite in the range of 0–20 mass% of the solid phase is studied.
Influence of various factors on the spreading kinetics
Authors: Novosadov V S , Dadashev R Kh , Kutuev R A , Elimkhanov D Z , Dadasheva Z I , Talkhigova Kh S 
Published: August 2020

Abstract
It was found that at the stage of fast spreading (τ≤ 0,02c) at constant driving force within the wetting perimeter, the following exerts the main impact on the spreading kinetics: inertial forces that prevent spreading and change their sign when the speed slows, viscous resistance forces, the influence of which increases in proportion to the growth of the thickness of the boundary layer and vertical forces, which begin to appear when the spreading velocity slows down.
Self-consistent model of fluid structure in volume and boundary layer
Authors: Novosadov V S , Dadashev R Kh , Kutuev R A , Elimkhanov D Z , Dadasheva Z I , Talkhigova Kh S 
Published: August 2020

Abstract
The study proposes the self-consistent theory that combines an activation model, a free volume model and a cluster model. The theory makes it possible to explain why the flow of fluid in slip conditions requires extremely minimal tangential stresses and describes the real structure of the fluid in the boundary layer, as well as to explain why the fluid is almost not squeezed out of the capillary gap.
Features of deformation and destruction of fine-grained fiber concrete
Authors: Maslennikov S A , Pashkova O A , Dmitrienko V A , Rud D O 
Published: August 2020

Abstract
The article analyzes the conditions of buildings construction in town Shakhty after the closure of coal mining enterprises. The appearance of deformation processes after old mine workings were flooded, is usually accompanied by uneven surface deformations and cracks formation in load-bearing structures is noted in the article. The positive effect of polypropylene microfiber additives on the deformation properties of Portland cement masonry solutions was studied, as it significantly reduces the probability of cracks in building structures. The results of experimental studies of mechanical properties of compositions with optimal dosage of polypropylene microfiber are presented. An increase in flexural and compressive strength of microfiber-modified samples was noted in comparison with the control ones. The dependence of ultimate deformations on normal stresses is established, which allows predicting the permissible ultimate deformations of masonry. The module of the total solution strain was evaluated.
Anomalous character of temperature dependences of some AgInSe2 parameters AgInSe2
Authors: Matiev A , Uspazhiev R , Khamkhoev B , Torshkhoeva Z , Blagina L , Gachaev A , Martazanova L , Evteeva R 
Published: August 2020

Abstract
Based on the experimental and X-ray studies of the absorption spectra and the temperature dependence of the crystal lattice parameters of AgInSe2 single crystals and the coefficients of thermal expansion along the corresponding crystallographic directions were calculated. It was found that the thermal expansion of AgInSe2 crystals along the a and c axes changes its sign at a temperature of 142.31 and 135, 14 K, respectively. The anomalous nature of the band gap width AgInSe2 was established.
Phase transformations and dielectric characteristics of FE-relaxor Sr0.75Ba0.25Nb2O6 ceramics and thin films
Authors: Pavlenko A V , Tolmachev G N , Stryukov D V , Alikhadzhiev S Kh , Aliev I M , Zhidel K M , Tsebaev S N , Dzhambulatov R S 
Published: August 2020

Abstract
In the paper the results of a structure and dielectric properties study of ferroelectric-relaxor Sr0.75Ba0.25Nb2O6 (SBN-75) ceramics and thin films with the structure of an unfilled tetragonal tungsten bronze have been presented. The existence of orientation domains in the SBN-75 film with rotation in the interface plane only by angles of ± 18.4° relative to the axes of the MgO substrate is revealed. In the tetragonal approximation, the unit cell parameters of the film (c = 3.948 Å and a = 12.49 Å) and its strain in comparison with the cell parameters of the ceramic sample have been determined.
External impacts on structure and relaxation properties of thermotropic liquid crystal copolyester
Authors: Zhukova G S , Radjabov Z R , Kurbanmagomedov A K , Boykova G V 
Published: August 2020

Abstract
The methods of thermally stimulated depolarization (TSD) and X-ray diffraction analysis were used to study the impact of electric and temperature fields on the relaxation properties, structure, and molecular mobility of a liquid crystal (LC) copolymer based on polyethylene terephthalate (PET) and n-hydroxybenzoic acid (n – HBA). It was shown that polarization in the LC state besides the main relaxation transition leads to the formation of additional high-temperature maximum on current thermograms of thermally stimulated depolarization (TSD). The data of X-ray diffraction analysis indicate a change in the orientation of mesogenic units after polarization in an electric field. The results were explained by the combined action of electric and temperature fields on the conformational structure of the liquid crystal copolyester, namely, a change in the degree of crystallinity of the studied copolyester under the influence of external fields.
Morphology of geophysical fields of Terek-Caspian trough and placement patterns of oil and gas structures
Authors: Abubakarova E A 
Published: August 2020

Abstract
The paper considers the characteristic morphological features of geophysical fields caused by fault tectonics of the Tersko-Caspian trough. The results of the interpretation of the gravitational and magnetic fields of the region using the Cascade 3D spectral-correlation analysis of data are presented. Computer technology made it possible to analyze three-dimensional digital geophysical information using the methods of a probabilistic-statistical approach. Linear positive anomalies of geophysical fields are identified that extend in the fault zones. A comparative analysis of the maps of transformants of the gravitational and magnetic fields and maps of oil and gas structures. Based on the results of comparative analysis, a dependence was established that characterizes the confinement of the known oil and gas deposits in the region to the zones of positive linear anomalies of geophysical fields of a sub-latitudinal strike.
Determination of multistoried buildings stiffness properties in the inverse dynamics solution
Authors: Sobolev V I , Sobolev I V , Druzhinina T Ya 
Published: August 2020

Abstract
The article is devoted to the development of methods and evaluation of the accuracy of determining the horizontal stiffness of multi-storey buildings basing on the results of instrumental measurements of the self-induced vibrations parameters carried out with the help of high-precision instruments. The proposed studies are extremely relevant in estimating the unsoundness degree of the buildings that have passed a certain period of operation or buildings that have been subjected to severe exposure. The use of dynamic methods of load-bearing structure condition analysis has undeniable advantages, since it excludes the need for a detailed examination, often associated with the necessity to open the enclosing structures and evict the residents of the building. The advantages of using this approach are particularly evident in the survey of a large array of residential buildings that are in heterogeneous operating conditions and require rapid results. The practical application of the methods was tested in the survey of the high-rise apartment buildings of 1-335 series in the city of Irkutsk. However, the need to use dynamic models of small dimension in the evaluation of stiffness parameters makes it inevitable and urgent to solve the problems of assessing the accuracy of such approximations.
Application of RAPID technology for well drilling
Authors: Guseynova E L 
Published: August 2020

Abstract
The article is devoted to multilateral drilling, it provides a brief history, relevance of application, development prospects, advantages. The history of the emergence and development of the unified international classification of multilateral wells the TAML is also described in detail. The article summarizes the characteristics of the six difficulty levels of the TAML Classification System. The use of advanced RAPID brand joints is described and analyzed in detail. Various designs of joints of the Rapid brand are considered. The authors also propose the construction of a multilateral well using a connector of the Rapid X type.
Cyclic impact on productive formations of high-viscosity oil deposits
Authors: Kotenev Yu A , Mukhametshin V Sh , Sultanov Sh Kh , Kotenev A Yu 
Published: August 2020

Abstract
It is shown that the priority condition for reliable forecasting of the cyclic impact on productive formations of high-viscosity oil is the joint research and study of rheological and filtration properties of high-viscosity oils, including thixotropic properties, as well as mathematical calculations to choose the right mode of the working fluid injection. For the Stepnoozerskoe field conditions, the optimal injection period is 10 days.
Accounting of time factor during bottomhole zone treatment
Authors: Mukhametshin V V , L Se Kuleshova 
Published: August 2020

Abstract
It was found that when treating the bottomhole zone with acid compositions preventing emulsification in terrigenous reservoirs, the time factor has a significant influence on the treatment efficiency, much more than the features of the geological structure of an objects. The algorithm, which allows reducing the negative influence of the time factor on the efficiency of oil production intensification by application of technological impact indices, is proposed. Geological-statistical models were obtained, which allow planning the treatment efficiency, selecting wells and technological treatment indicators taking into account the time factor in real time.
On the development of an experimental design and field test of an upper bit tool
Authors: Zaynagalina L Z 
Published: August 2020

Abstract
The design of upper bit tools has been developed. Such tools provide crushing, sifting and removal of slurry from the bottom when drilling vertical, deviated and horizontal wells with a roller cone bit. The analysis of slurry samples from directional and horizontal wells was carried out to determine rational geometric dimensions of the working channels of the upper bit tool. The design requirements of upper bit tool, ensuring the stability of its operation, are presented.
The actualization of the garden city model in modern urban planning with participation practices (on the example of Grabnyk park renewal in the city of Rivne)
Authors: Blinova M Y , Ilchenko S A 
Published: August 2020

Abstract
The participation practices in Ukrainian urban planning are a fairly new phenomenon. The growing interest in such approaches primarily reflects positive changes in the development of cities. On the other hand, this interest draws attention to problems of implementation of these approaches in actual urban planning practice. It is important to note here that although participation practices are well regulated in countries with developed democracy, under conditions of developing democracy in Ukraine there are still no well-functioning mechanisms of interaction between government and society at local levels. Regarding participation of local communities in city development, the discussion about the place of a professional architect in urban planning processes that include participation practices becomes particularly important. In this article we uncover effectiveness of participation practices and limitations of their application in the context of Ukraine. We also determine the differences in understanding effectiveness and limitations of these practices in Ukraine and developed democracies.
Sustainable Mobility in the Context of Humanization of the Urban Environment: a regional experience
Authors: Korshunova N N , Morozova E B , Dolinina O E 
Published: August 2020

Abstract
The purpose of the research is to identify modern approaches to the spatial development of Belarusian cities. The article focuses on the role of transit-oriented design in spatial development of cities. The principles of ‘green urban construction’ and their implementation in pilot projects for urban areas reconstruction in Polotsk-Novopolotsk agglomeration are considered. The introduction of developed territory transformation models into urban planning practice was suggested. The participation of Belarus in international initiatives and projects relating to urban and transport planning are assessed. Organizational and institutional prerequisites for using the European experience of mobility management have been established. The scientific novelty consists in the study of the concept of sustainable mobility as a tool for territorial development and humanization of the environment with a focus on the conditions in Belarus.
Problems of Architecture and Professional Development of an Architect beyond “Limits to Growth”
Authors: Fomenko O O , Danylov S M , Izbash A M 
Published: August 2020

Abstract
The study examines the regional specifics of the formation of architectural specializations under the influence of social and resource crises experienced by Ukraine. Based on the work of D. Meadows and J. Forrester (system dynamics) a method was developed for the formation of “Knots of problems” based on “positive and negative feedback loops”. Some “Knots of problems” and their influence on the formation of needs for architects and urbanists of the new generation were described on the example of Kharkiv. The identified needs are shaped by the acute socio-economic crisis experienced by the city. The authors argue that a focus on servicing territorial communities and developing strategies to enhance the role of society in creating an energy-efficient and environmentally positive architecture should be considered a prority in the work of architects of new formation. The research based on the identified socio-economic “Knot of Problems” describes its hermeneutic circle (a circle of interconnected systemic contradictions that prohibits the solution of identified problem). The analysis of the revealed “Circle” indicates that an achievement of a sustainable state by the cities of Ukraine is practically impossible without a significant increase in socialization in urban communities. The study focuses on the importance of universities and, in particular, architectural faculties, in the revival of territorial communities.
Peculiarities of erecting walls for houses and buildings by technology of monolithic construction using permanent formwork unit
Authors: Butnik S V , Viatkin V A , Dzhalalov M N , Hovorukha I V , Bielka V V 
Published: August 2020

Abstract
The article deals with constructive and organizational-technological solutions when performing works on construction of external and internal bearing walls with the use of combined permanent formwork. The technology allows to reduce the construction time by combining in the system of the retained formwork unit three technological processes, which are performed simultaneously by one group of contractors - erection, insulation and wall decoration. Depending on the thickness of the insulation in such houses and buildings, it is possible to achieve close to zero energy consumption.
Role of potential-determining ions and water molecules in the structure formation of cement compositions
Authors: Plugin A , Kostyuk T , Bondarenko D , Pluhin O , Arutyunov V 
Published: August 2020

Abstract
The paper is concerned with dealing with an urgent problem of present-day construction materials science and engineering such as increasing the strength of cement stone when using finely dispersed fillers. It has been found that the physical and mechanical properties of Portland cement-based materials largely depend on the strength of the cement matrix modified by finely dispersed fillers, in particular, on the electric surface properties of all components and pore walls (equilibrium electric surface potential and double electric layer with potential-determining ions and counter-ions and at the interface between the solid phase and water). Studies were conducted to determine the values of equilibrium electric surface potentials of perlite and glass hollow microspheres. The system-forming hierarchical structure of water acting as a matrix or a crystal-forming platform for the synthesis of spatial structures during the formation of a crystalline cage on the surface of micro-fillers was substantiated. The assembly elements of these systematized structures were investigated using electron microscopy. It should be noted that when water films are supersaturated with ions during cement hydration, crystals nucleate and grow on the surface of micro-fillers, which leads to self-compaction and hardening of the cement matrix at the microlevel.
Modification of the structure of the stabilized basalt fiber
Authors: Gots V I , Palchyk P P , Tymoshenko S A , Palchyk S P 
Published: August 2020

Abstract
The study of thermophysical, physical-mechanical and acoustic characteristics of coarse continuous basalt fiber in the conditions of influence of operational factors and corrosion environment is carried out. It is shown that obtaining barrier materials with high thermophysical and acoustic properties is possible by creating a porous system in the material with a predetermined textural characteristic of pores of different class, purpose and combination. The influence of the porous system of coarse continuous basalt fiber on the operational properties of flexible heat and sound insulation products and materials has been studied. It is determined that the performance characteristics of flexible thermal insulation materials are in direct proportion to the degree of porosity of the constituent materials and their structural characteristics. Shown that the increase in the operating temperature of these materials, sound and thermal resistance is determined by the chemical and mineralogical composition of the source materials and their structural characteristics. The influence of the mechanism of selective leaching of coarse continuous basalt fibers on their textural characteristics and the zone of operating temperatures is studied.