bluuebunny/crossref_metadata_2025 huggingface dataset:
Determining the optimum heating time of small sized test specimen made from weldable mild steel
Authors: Tancsics F , Ibriksz T
Published: August 2020

The usage of CHT (Continuous Heating Transformations) diagrams for a given steel or equivalent grade, requires knowledge of heating temperature, average heating rate, and the heating time. Definition of these technological parameters are primarily based on the complex relationship system between the geometric, thermal parameters and the heating device. In our research, we mainly focused on those physical key parameters that can mostly influence the heating and transformation rate. These parameters provide realistic, usable data for analysing the process of thermal diffusion and FEA (Finite Element Analysis) tests. During analysis, an easy-to-use function relationship was determined for approaching the heating rate more precisely. This method allows handling the CHT charts easily, within a selected range, regarding weldable mild steels.
Wetting of Non-Reactive and Reactive Metallic Substrates by Brazing Liquids
Authors: Weltsch Z
Published: August 2020

A survey of wetting as central phenomenon in soldering and brazing technologies are presented in this paper. The wettability is expressed by the magnitude of wetting angle. The equilibrium condition is widely investigated in the case of non-reactive partners. The phenomenon is less documented in the case of reactive partners, when chemical reaction (hence, local compositional change) also occur between the contacting phases. The brazing process belongs to this category. The mutual wettability is basic requirement for the formation of strong and durable bonding between the machine parts. Therefore, the correlation between the wetting angle (Θ) and the strength of the resulting bonding will be investigated. Not only the chemical concentration change, but phase transformations may also occure in such brazing procedure, when the contacting partners are reactive. As the chemical potencial of components are also change in this cases, the phase transformations has also impact on the evaluation of wetting angle between the brazing pool and alloy pieces to be joined. This phenomena will also be demonstrated in the case of non-reactive and reactive partners as well.
Conservation purpose material testing of corrosion products on outdoor bronze statues
Authors: Szilvia Szilvia , Nagy Melinda , Juhász Laura , Bubonyi Tamás , Péter Barkóczy , Forgács György , Szatmáriné Bakonyi Eszter
Published: August 2020

A detailed material testing was carried out before the conservation project of the János Arany statues of Garden of Hungarian National Museum. The scope of the testing to analyse the corrosion products on the surface and help to develop the best cleaning and protection practice. Samples were taken from more areas and the samples were analysed by SEM-EDS, XRD, FT-IR methods. This article introduces the results of the testing and the relevant effect to the conservation process.
Preparation of soft magnetic composite from Fe-6.9wt%Si by different heat treatment strategies.
Authors: Kocsis Bence , Varga Lajos Károly , Zsoldos Ibolya
Published: August 2020

Present study investigated the effect of isothermal heat treatment strategies between 800 °C and 1150 °C on the magnetic properties of toroidal samples made from Fe-6.9wt%Si powder. The samples were prepared by classical powder metallurgy method since the classical sheet forming methods no longer work with the high silicon content. Our results presented here are part of a series of comparative experiments where we study the effectiveness of the insulating layers created during and before the compacting of soft magnetic composites (SMCs). Our goal was to create a soft magnetic composite made of ferromagnetic and inorganic insulating material with a frequency limit already in the megahertz range and a Snoek limit of few gigahertz. In the case of samples made from Fe-6.9wt%Si powder, the computed tomography results showed that significant porosity is to be expected after pressing. Its positive effect occurred during the heat treatment in the atmospheric agent, where silicon is precipitated and deposited on the surface of the particle. This coating is an electrically insulating layer at the grain boundaries. Depending on the heat treatment strategy, 1 or 2 ferromagnetic phases were observed. The frequency limit approached the target values, but due to the low value of static permeability, the Snoek limit did not reach the gigahertz range. However, there is a significant improvement in magnetic properties compared to the heat-treated samples in a protective gas.
Effect of Beracha-I type color etchant on the ferrite phase in different type Fe-C alloys
Authors: Renkó József Bálint , Bonyár Attila , Jánoš Szabó Péter
Published: August 2020

In material science, and particularly in metallography, various etching processes are frequently used to visualize grain structure. For some etching processes, it is sufficient to immerse the specimen into the etchant only for a few seconds, but for color etching, samples must be kept in the etchant for several minutes to achieve a colored surface layer. In our research, a measurement environment was created, in which the process of color etching can be observed in real-time. A closed microfluidic system ensured the controlled laminar flow of the etchant. The surface of the observed spherical graphite cast iron and DC01 low carbon steel was monitored from the beginning to the end of etching. Comparing the etching of the spherical graphite cast iron and the low carbon steel samples give a more comprehensive picture of the effect of Beraha-I type color etchant on the ferritic structure. Though the etchant reacts with the same ferritic phase in both cases, the etching process develops in different ways. The layer formation was much faster in the ferritic phase of DC01 steel, compared to ferrite in cast iron specimens.
On kinetics of transfer of interphase borders during contact melting with an electric transfer
Authors: Bagov A M , Khasanov A I , Zubhadzhiev M-A V , Umarova L Kh
Published: August 2020

The mathematical laws of kinetics of the liquid zone growth under the contact melting of binary metal systems in the presence of constant electric current were described; the analytical and graphic solutions to this problem explain the experimental data.
Stable Tetrahedron NaCl – KCl – PbCl2 – PbWO4 in the quaternary reciprocal system Na, K, Pb // Cl, WO4
Authors: Kochkarov Zh A , Baysangurova A A , Khasbulatova Z S , Khubaeva M V , Alarkhanova Z Z , Bataev D K-S , Maglaev D Z
Published: August 2020

The phase diagram of the stable tetrahedron NaCl – KCl – PbCl2 – PbWO4 of the quaternary reciprocal system Na, K, Pb // Cl, WO4 was first studied using methods of differential thermal analysis. Its phase diagram was triangulated and stable triangulating internal sections of NaCl – PbWO4 – KCl.2PbCl2, NaCl – PbWO4–2KCl. PbCl2 and obtained tetrahedra NaCl – PbCl2 – PbWO4 – KCl.2PbCl2, NaCl – KCl – PbWP4, and NaCl – KCl – PbWP4. There are coordinates of three quadruple invariant points revealed.
Geotechnical monitoring
Authors: Gairabekov I G , Kaimov Sh S-E , Mishieva A T , Ibragimova E I , Gairabekov M-B I , Gayrabekova A I
Published: August 2020

The paper considers methods of observation over foundation settlement of buildings and structures on the southern slope of the Veduchi Ski Resort and its accompanying infrastructure. The study was carried out from control stations via geometric levelling of the II class. Based on the results of two observation cycles, the settlement values were obtained, all buildings and structures settled within 0.4–2.2 mm. Based on the data on the limit permissible values presented in the paper it can be concluded that buildings and structures on the southern slope of the Veduchi Ski Resort and its accompanying infrastructure are within the permissible settlement values.
Geodynamic features of the territory of Grozny city
Authors: Gaysumov M Ya , Kerimov I A , Badaev S V , Gaysumov O M , Doduev A A
Published: August 2020

The work contains data on tectonic structure, modern geodynamic activity and materials on the study of negative exogenous processes obtained as a result of the development of oil fields located on the urban land. The analysis of geodynamics of the Tersko-Sunzhen structure located in the central part of the Tersko-Caspian deflection was performed. The history of the formation of this tectonic zone is long and diverse and is determined by its fault-block tectonics. At the present stage, the territory is also defined as geodynamically active, consisting of blocks bounded by faults and fractures, which are characterized by intense movements of the earth’s surface. Stress unloading is expressed in the deformation of rock massif and in case of rapid (stepwise) unloading of tectonic stresses – through earthquakes. A special condition is that Starogroznenskoe and Oktyabrskoe oil fields are located on the territory of the city. To date, the cumulative production amounted to more than 150 million tons of oil. Long-term development of deposits led to equilibrium disturbances of the geological environment with significant change of formation conditions and accordingly to the development of hazardous geodynamic processes.
Synthesis of group compressed-air sources for marine seismics
Authors: Gulenko V I , Zakharchenko E I , Rudakov A V , Zakharchenko Yu I
Published: August 2020

The improvement of geological efficiency of marine seismic survey implies continuous improvement of the entire technological complex used in water areas. This is typically accomplished by using complex linear or spatial non-uniform compressed-air groups. In the development of such sources, in addition to solving a number of purely technical problems related to their placement on board the ship and safe operation, one of the most difficult tasks is to determine the initial requirements for selection of the main parameters of the group, such as the volumes of working chambers sources and geometry of their grouping, as well as other factors determining amplitude, time and frequency of emitted acoustic signals. This study considers the main principles of grouping the compressed-air sources for marine seismic survey. It is shown that the most important factors determining the choice of source parameters and specific research technology include the nature of geological tasks and seismic conditions, which primarily depend on the sea depth in the study area. A simple method of calculating the configuration of linear subgroups with fluctuation suppression is described, as well as examples of building linear and spatial groups based on them with pronounced directional properties are considered.
Resource-saving technology of ceramic brick production with nickel slags of Orenburg Region
Authors: Gurieva V A , Ilina A A
Published: August 2020

The paper considers the problem of using technogenic products in the production of construction materials thus obtaining ceramic products with specified properties both in Russia and abroad. It provides data on chemical and mineralogical composition of initial raw materials, defines pre-calcination and calcination properties of clay and nickel slag. Compositions with different percentage of clay/slag are developed and two-factor experiment is carried out, where the first factor is the percentage of slag in a sample, while the second factor is the sintering temperature of samples. The diagrams show the influence of material composition of clay/slag charge mixture on compression strength, water absorption and density of test samples after firing at a temperature of 900, 950, 1000 and 1050 °C. The obtained results allowed identifying the need for sintering of masses from clay of Khalilovsky deposit with nickel slags of OAO Yuzhuralnickel of Orenburg Region in the production of ceramic brick.
Analysis of carbon fiber destruction by lighting current
Authors: Guschin I A , Erina T N
Published: August 2020

The paper considers the unique properties of conducting carbon fiber composite: specific resistivity at different directionality of layers and critical energy of layering and destruction on the basis of experimental data. High mechanical strength and low specific gravity are noted, allowing its use in aircraft engineering to improve aircraft tactical and technical data of aerial vehicles. Strong anisotropy of electrically-conductive properties affects current spreading through carbon fiber and leads to significant destruction of the material. Theoretical analysis of lightning current spreading along anisotropic-conducting material in the form of extended plate was carried out on the basis of two proposed models of carbon fiber destruction by lightning currents. For the first continuum model an exact analytical solution to the Laplace equation with Neumann boundary conditions via the Greenberg method was found. The criteria for composite destruction was found, and the radius and depth of destruction of a conductive material by lightning current were calculated. Layer-by-layer destruction is considered on the basis of carbon fiber equivalent circuit. The strong anisotropy of the material resulting in the release of full energy in the first layer is taken into account. It is shown that the destruction of the top layer changes the distribution of currents over the remaining layers. The results of numerical modeling of layer-by-layer destruction of carbon fiber for different number of layers are given. The conclusion on the application of criteria to forecast the lightning effects and optimize lightning at the stage of aircraft design is made.
Hybrid modeling of wave processes in the scientific justification of hydraulic solutions
Authors: Kantarji I G
Published: August 2020

To determine the wave or ice load on offshore hydraulic structures, calculation methods and modern mathematical models are used, as well as field observations and laboratory studies. Each of these methods has advantages and disadvantages. Sharing existing methods provides an approach called “hybrid or composite modeling.” Hybrid modeling provides the most reliable approach for designing safe facilities. However, the interaction of the individual components of hybrid modeling requires further research. This article is devoted to the study of the problems that arise when verifying the results of numerical modeling of wind waves using field and laboratory model measurements. The experience of studying the projects of the port-shore protection complex in Imeretinka, Sochi, the LNG terminal in the Ob Bay and the port in the East Bay of the Sea of Japan is used.
Identification of intermittent point source capacity and location of the initial contamination plume
Authors: Kochergin V S , Kochergin S V
Published: August 2020

While working on a model of mass impurity transition for the waters of the Sea of Azov and the Kerch Strait, we calculated the capacity of the immediate point source and identified the location of the initial contamination plume. Contamination source capacity identification is based on minimizing the quadratic functional of the forecasting quality and solving associated problems. Associated problem solving is also used in order to identify the location of the initial contamination plume in the body of water under analysis. The first goal was reached for the Gulf of Taganrog area, and the second one – for the Kerch Strait area. It must be noted that both areas have heavy marine traffic and experience the construction of new transport corridors. Simulation results were produced taking into consideration north-western winds that are dominant in the region. Quantitative experiments show that it is possible to identify the capacity of an intermittent point source of contamination using a three-dimensional model of mass impurity migration, as well as to identify the location of the initial contamination plume.
Asphalt concrete on the basis of converter slags
Authors: Kovalev N S , Otarova E N , Gladnev V V , Sadygov E A ogly , Demidov P V , Panin E V
Published: August 2020

The properties of converter slag, its activity and the influence of the degree of decay on the structural and mechanical properties of asphalt concrete are studied. It has been established that asphalt concrete with a degree of decay of converter slag of 1.24 % or less can be used for paving roads. It has increased heat, water and frost resistance, which will significantly increase the service life of roads from the beginning of operation to overhaul.
Automation system for oil and gas service enterprises
Authors: Remizova I V , Krugovaya T S , Krotova S Yu , Ovchinnikova E N
Published: August 2020

The paper presents the results of the development of a single integrated solution for the automation of technological processes of service enterprises of the oil and gas sector, which allows to organize the work of production and management in a single information space. Algorithms have been developed to solve individual problems that are interconnected into certain algorithmic modules. The results of the integration analysis of modern automation systems of the ERP-class are presented, in particular, the level of adaptation to the stages of the product life cycle, compliance with standards and safety requirements, the complexity of the transition to the automation system. The results of the analysis of possible risks of the project during the implementation of this algorithm are presented. The practical significance of the development of a single production management algorithm is described. Finally, the treatise evaluates the main advantages and economic effect of the introduction of an automation system for an enterprise engaged in the production of oil and gas pipes at the process control level.
Technology for the formation of refractory metals for micro- and nanoelectronics products
Authors: Mustafaev G A , Khasanov A I , Cherkesova N V , Mustafaev A G
Published: August 2020

Metal silicides play a significant role in the preparation of ohmic contacts and Schottky barriers on silicon. The formation of ohmic contacts is carried out by applying a metal film with a thickness of ∼ 100 nm to silicon, followed by annealing at temperatures of 400–600 °C, as a result of which there is a reaction between silicon and metal with the formation of silicide. With this technology, silicon diffusion leads to instability of devices. In this regard, the authors developed an improved technology for the formation of silicides of refractory metals to obtain ohmic contacts. Ion implantation allows, due to ionic mixing, forming nickel silicide on the surface of the samples when heated. It is important that, with an increase in the radiation dose, the formation of Ni2Si silicide slows down. This effect can be explained by the formation of a dielectric Ni3Si2. Similar phenomena were observed during the bombardment by oxygen and nitrogen ions.
Anticorrosion properties of manganese-containing complex oxides, obtained by stoneware method
Authors: Nurislamova E A , Ziganshina M R , Stepin S N , Mendelson V A
Published: August 2020

In recent years, in the search for alternatives to toxic anticorrosive chromium pigments, the use of complex metal oxides in this capacity has been actively developed. In this work, the anticorrosive and other physicochemical properties of complex oxides, including manganese in oxidation degrees +4 and +5, obtained by the calcination method were investigated. As a result, it has been shown that the products obtained have good prospects for being used as anti-corrosion pigments. Higher inhibitory properties of pigments containing manganese in oxidation state +5, is probably a consequence of their aqueous extract’s alkaline reaction. During the experiments, it was found that the competitiveness of the synthesized pigments can be markedly enhanced by using natural ore, pyrolusite, as manganese source.
To a question of a choice of a method of production of construction works on set of technological cards
Authors: Sinenko S A
Published: August 2020

The need to create an automated system for selecting rational organizational and technological solutions based on modern design technologies. Methods. Based on known BIM building information modeling objects are created by the Bank (information base) of typical technological cards (TC) from which the method of the study criteria based on modified genetic algorithms (GA) is the most efficient TC for this type of work. Results. The article deals with the choice of the method of production of construction works on the set of technological maps of construction and installation works. Conclusion.
Visualization of process maps for construction and installation works
Authors: Sinenko S A , Aliev S A
Published: August 2020

the article presents the principles, methods and means of visualization of organizational and technological solutions developed as a part of technological maps for the production of construction and special operations. In this paper, the authors analyze the possible ways of the development of visualization of organizational and technological solutions. The examples of 3D images of the main production schemes as a part of technological maps for the installation of beams in machine rooms in the building of hydroelectric power plants are shown. The developed display techniques can be used in the practice of the design of technological maps for the production of construction and special operations. This technology will expand the scope of modern design tools in the practice of construction production.
Properties of foam concrete based on highly concentrated aluminosilicate binder suspension
Authors: Sivalneva M N , Strokova V V , Kobzev V A
Published: August 2020

Cementless binders and building materials are promising. The article presents results of production of foam concrete compositions using high-concentration aluminosilicate binder suspension based on granodiorite. Their basic physical and mechanical characteristics and microstructural features are described. The method of multifactor experiment was used, which allows to vary the parameters: water-solid ratio, amount of binder component and stabilizing additive. Thus, during steps of mathematical planning, optimal parameters were recommended, the observance of which is necessary to obtain cementless cellular composites with the best properties.
Preliminary assessment of the earth’s surface movement in the impact zone of a subway tunnel construction
Authors: Alekseev G V , Medvedev E A , Tereshin A A
Published: August 2020

Numerical modeling of the displacement of the earth’s surface during the construction of deep tunnels is considered on the example of one of the Moscow metro lines. Based on the results of numerical simulation of the driving of one and two tunnels using several calculation schemes, the forecast parameters of the displacement trough, such as subsidence, slopes, curvature, horizontal deformations of the earth’s surface, are determined. According to the criteria of deformations of the earth’s surface, a tunnel influence zone is constructed. In the influence zone of tunnels, it is necessary to create observation stations for surveying (geodetic) monitoring of subsidence of buildings and the earth’s surface, including using automated monitoring systems. According to monitoring data, the parameters of the calculation models are adjusted to increase the reliability of the simulation results. A technique is proposed for a preliminary assessment of the displacement of the earth’s surface in the influence zone of the construction of subways tunnels.
Unconventional raw materials in silicate materials designing based on technogenic metasomatism knowledge
Authors: Volodchenko A , Lesovik V , Volodchenko A , Cherepanova I
Published: August 2020

A large number of scientific schools is working over improving existing building materials and designing some new composites for various functional purposes, where the composites properties play a very important role. However, priority is given to the initial properties of building composites but one of the main indicators by which these properties could be evaluated after prolonged use and under the influence of natural and man-made processes is durability. The study on building materials under changing operating conditions, based on unconventional natural and man-made materials is becoming very interesting and relevant for today. The theoretical basis for increasing the durability of building materials may be the theoretical knowledge of technogenic metasomatism in building materials science. It has been established that the use of unconventional natural and technogenic raw materials, in particular unconventional clay rocks for production of hydrothermal hardening silicate materials will help to achieve the necessary structurization level and maximum physic-mechanical properties of highly efficient wall products under various operating conditions.
Prospects of applying formation water and heavy brines derived therefrom in oil production and national economy
Authors: Kadyrov R R , Mukhametshin V V , Galiullina I F , Kuleshova L S , Safiullina A R
Published: August 2020

In recent years, the amount of minerals recovered from the earth interior exceeds their production over the entire past human history. The reserves of some rare elements have been significantly reduced and the demand for them has increased dramatically through the use of new techniques and technologies. The task of developing new types of mineral raw materials from formation waters has become ever more relevant. In the process of formation water preparation during the production of table salt the fluids and heavy brines are obtained, which are suitable for their further use in oil production. The fluid obtained through deferrization of formation water has reduced content of magnesium ions. The use of this fluid makes it possible to increase the mechanical strength of the cement stone, the tightness of the “column-cement stone” contact zone, and to reduce magnesia corrosion.
The use of variable frequency drive for the operation of the NBT mud pump
Authors: Suleimanov R I , Khabibullin M Ya
Published: August 2020

The article discusses the process of optimizing the operation of the NBT-600 mud pump by adjusting the frequency of the current supplied to the pump drive. As a result of a technical measure, efficient operation of the pump is ensured, the energy consumption of the pump unit is reduced, and the main parameters of the pump are increased.
Schools of architecture as an instrument of architectural policy on the examples of European countries
Authors: Yesipov A O , Myronenko V P , Ivanova N V
Published: August 2020

The purpose of this article was to analyze the cultural policies in the field of architecture in various European countries and consider the principles of using the tools of schools of architecture as its element. Such issues are especially relevant for Ukraine, where the problem is the lack of regulated norms for Ukrainian architectural policy and specialized state institutions. The need to draw attention to the architectural education of Ukraine is due to its lack of actualization compared to advanced European countries and the depletion of the physical plant of universities. An analysis of foreign experience will make it possible to use the potential of universities to solve the problems facing the society.
The problem of formation of innovative directions in the profession “Architect”
Authors: Fomenko Oksana , Danylov Serhii , Sleptcov Oleg , Izbash Andrii
Published: August 2020

The paper investigates the phenomenon of the impact of innovation on the formation of competencies, specializations and specialities in the profession “Architect”. A research model is proposed that describes the impact on the profession of innovative, architectural and construction factors and the goal-setting factors of innovative knowledge and technologies. The features of the influence of changes in the socio-economic factor of the functioning of Kharkiv (Ukraine) on the formation of new urban areas in architecture are described. An experiment is described to create a cognitive model of the “Novi Doma” housing estate, Kharkiv, in which the authors of the study participated as expert architects. The deep socioeconomic crisis of the housing estate revealed and described in the experiment made it possible to draw conclusions about the parameters of a new scientific and educational direction in urban studies.
Reactive powder concrete incorporating metakaolin and fly ash for monumental architectural objects
Authors: Dvorkin L , Zhitkovsky V , Lushnikova N , Fursovych M
Published: August 2020

The paper gives coverage on the properties of reactive powder concrete, incorporating metakaolin and fly ash and polyacrylate superplasticizer. There are given results of comparative research of reactive powder concrete (RPC) containing silica fume. There are also considered the impact of curing conditions on the strength of RPC specimens. The combination of fly ash and metakaolin is the effective composite mineral additive that allows to obtain RPC without silica fume. The optimal dosage of metakaolin in composite admixture from the point of maximum flexural and compressive strength was about 10% by cement weight. The curing of the RPC specimens in the hot water at t=80°C increases compressive strength of concrete at 20-25%. Adding the combination of metakaolin and fly ash with permits to achieve RPC high values of mechanical properties compatible to RPC containing silica fume. High fluidity of fresh concrete along with high performance of hardened concrete allows to apply RPC for manufacturing architectural elements of non-linear geometry, thin structures, and other.
Architectural construction using technologies based on knowledge about the flow of Bingham plastic fluids in various pipelines
Authors: Zadorozhnyi A A
Published: August 2020

Currently, such types of engineering work as construction of classic buildings and structures, as well as erection of new ones that have an irregular shape, i.e. curved, arched, elliptical, round and similar surfaces, can be performed using complex technological equipment, such as combined external or internal formwork, the use of shotcrete technology together with the off-formwork construction technologies (3D printers). One of the prerequisites for uniform transportation of media by a concrete pump through pipelines, concrete conveying pipes, and most importantly, their homogeneous distribution by an extruder during layering, is a study based on mathematical modeling and comparative analysis of mathematical models of the flow of Shvedov-Bingham fluids in pipelines of various cross-sections, determining the performance, optimal rheological properties of mortars and concrete liquids. This will allow further control of their fluidity and plastic viscosity during the extrusion process.
Radiation protective properties of fine-grained concretes and their radiation resistance
Authors: Anopko D V , Honchar O A , Kochevykh M O , Kushnierova L O
Published: August 2020

Studies have shown that the thickness of the half layer of the gamma radiation flux attenuation with E = 662 keV is 3,5-5,2 cm (depending on the concrete density average) and for a neutron flux with E = 2,5 MeV is 5-6 cm. The radiation resistance of concrete under the influence of gamma radiation large doses, their activity and radionuclide composition after irradiation with neutrons was investigated. To study the behaviour of concrete under the influence of gamma radiation, two series of samples were made. One series was the control, and the second was exposed to gamma radiation. The temperature of the samples during testing did not exceed 40 °C, the dose of gamma radiation was 109 rad. Its value corresponds to the dose that concrete can receive when it comes into contact with highly radioactive wastes from the “Shelter” facility for 300 years. The characteristic of an industrial gamma-ray plant is radiation energy of 1,25 MeV and a dose rate of 2 Mrad/h. Using this setup allows you to reach a dose of 109 rad in less than a month, and 108 rad in 4 - 5 days. Concrete that reached the age of 28 days and stored under normal conditions was exposed to gamma radiation. Analysing the obtained data of physical and mechanical tests of radiation-protective compositions, it can be noted that large doses of gamma radiation practically do not affect the strength of the developed material.
Evaluation of the frost resistance of concrete in real operating conditions
Authors: Lapovska S D , Krasnianskyi G Iu , Klapchenko V I , Aznaurian I O
Published: August 2020

The article proposes a method for evaluating the frost resistance of concrete at actual operating temperatures, using measurement results at temperatures that are regulated by current standards. Frost resistance was evaluated by determining the amount of water freezing at different temperatures, based on the measured adsorption isobars and the obtained relationship between the freezing temperature of water in concrete pores and relative humidity. A comparison of the calculated values of the frost resistance of concrete with those got based on direct measurements showed the adequacy of the calculation model. To get information about the frost resistance of concrete during unilateral freezing, a conductometric method was used to determine the kinetics of moisture diffusion and ice formation. It is shown that the use of this method allows one to establish the propagation speed of the ice formation and water diffusion front and the corresponding freezing depth of concrete samples depending on their capillary-porous structure and initial storage conditions. In general, the studies conducted allowed us to get a more reliable picture of the behaviour of concrete under alternating temperature load than is provided for by current regulatory documents.
Manufacture of construction materials by energy-saving technology through the example of the Bashkir region
Authors: Gabitov A I , Ryazanova V A , Salov A S , Gaisin A M , Timofeev A A
Published: August 2020

Information on the history and formation of the production and application of efficient concrete walling items and road facilities in the construction practice is presented herein by studying historical data. Ways to improve quality of small walling items and road facilities to comply with current energy-saving requirements are analyzed from the historical point of view. Vibropressed technology became widespread over 40 years ago in North America and Europe, being characterized by high capacity and automation of equipment with abilities to manufacture wide spectrum of products by size, shape, finish and color distinguished by low material and energy intensity of production, efficiency of application thereof in energy-saving wall constructions. Special features in making vibropressed concrete items by Besser equipment in the Bashkortostan construction companies are presented.
Ecological efficiency photocatalytic concrete
Authors: Sopov V P , Shyshko N S , Kondrashchenko V I , Yihe Zhang
Published: August 2020

The process of urbanization is accompanied by the formation of a high density of street highways, buildings, people, transport and industrial enterprises, high energy consumption, an increase in the amount of waste and the release of a large amount of pollutants into the atmosphere and the aquatic environment. Air pollution is one of the most serious environmental problems in cities and poses a threat to vegetation, animals, materials and human health. One of the main environmental pollutants is nitrogen oxides (NOx). Finding ways to remove NOxfrom the surrounding air is a necessity today, as it will help to improve the ecology of large cities, as well as reduce O3concentration at ground level. Titanium Dioxide (TiO2) is a natural semiconductor material that is widely used in many industries. In construction, titanium dioxide is used to create building materials with a self-cleaning surface. In recent years, a fairly powerful photocatalytic effect of surfaces with titanium dioxide has been discovered. Self-cleaning combined with the photocatalytic effect of TiO2makes it an ideal additive in the production of building materials for urban environments. Depending on the application, TiO2can be used as a coating, additive in concrete, gypsum or paint. TiO2can be used for surfaces of paving elements or building facades, retaining walls, tunnels. In this paper, we study the effect of the addition of titanium dioxide on the formation of the physicochemical properties of concrete.
A study of the alkali-silica reaction in recycled glass concrete
Authors: Sopov V P , Korkh O I , Izbash M Yu
Published: August 2020

Recently, it has been paid more and more attention to the concept of sustainable development. One of these technologies is the production of “green concrete”. It can be created by replacing natural concrete aggregate with secondary one. Therefore, white glass cullet was used as a replacement for 30% of coarse and fine aggregates in this study to design “green concrete”. It was designed four concrete mixes for the investigation. Measurement of the fresh concrete mixes’ performance showed that the use of glass aggregates reduces its workability. But it can be increased by using chemical admixtures. The highest strength - 28.94% more than the control sample, was obtained by a sample that contained coarse of glass aggregate and had low water-cement ratio. Sample №3 had lower strength only for 1.62% than sample №1 among mixtures with normal W/c ratio. Исследование фазовых превращений показало
Architectural and Urban Planning Features of Ecotopia
Authors: Fedak A
Published: August 2020

This article has been devoted to the analysis of the description of architecture in the works of utopian philosophers, and the identification of the main means by which they tried to ensure the environmental friendliness of their society and connection with nature. Utopian ideas and concepts arise as a result of dissatisfaction with the standard of living and contribute to the active development of society. The models of states described in utopian works serve as a source of ideas for possible scenarios for improving current systems. Ecotopies are a specific type of utopias which describe states with a clear and exclusively ecologically-oriented social order. This article presents an analysis of architectural and engineering means of communication with nature in the works by Plato, T. More, T. Campanella, Cyrano de Bergerac, D. Vairasse and V. Odoyevsky. The work of E. Callenbach, as the first example of ecotopia, is analyzed in detail, and the peculiarities of the architecture and urban structure of the cities of Ecotopia are highlighted.
Peculiarities of Formation of a Systems Approach in Domestic Urban Planning
Authors: Ladigina I V , Rudenko A O
Published: August 2020

The formation of a systems approach to urban planning in Ukraine is considered, starting from the second half of the twentieth century. Territories with a high level of urban planning development were formed at the time as a result of the development of an industrial component of the production industrial complex, which became the basis for perspective formation of urban systems as real entities. The transition to post-industrial relations causes the increase in complexity of urban systems and their study as complex, open, non-linear, socio-territorial entities capable of self-organization as a real process that takes place in their structure.
An anamorphic time-lens-based optical cryptosystem for protection of time-varying signals
Authors: Wang Mingqing , Lou Shuqin
Published: August 2020

The similarity between in-plane directions of spatial optics and overlapped time ranges of temporal optics is introduced as a new rule of the space–time duality. Applying this rule, an optical dual random phase encoding (DRPE) cryptosystem in the temporal anamorphic fractional Fourier transform (TAFrFT) domain is proposed for physical-level protection of time-varying signals. The structure of a TAFrFT system is an anamorphic time lens (ATL) sandwiched by two identical dispersion elements. The additional key provided by a TAFrFT system is only related to phase profile of the involved ATL, leading to a dispersion-independent manner of key updating as well as an enlarged key space (KS) in comparison with the conventional temporal FrFT and Fresnel transform system. This manner of key updating has potential as a one-time key strategy to evade the intrinsic linearity and symmetry weakness of DRPE-like temporal cryptosystems, due to the updating speed being comparable to the frame rate of plaintext signals. As the temporal counterpart of a spatial optical device composed of cylindrical lenses along different directions, an ATL is designed as an equal-spaced array of time lenses with unipolar phase, constant extension, and varying phase height. Implemented by an arbitrary waveform generator (AWG)-driven electro-optic phase modulator (EOPM), the time interval of adjacent time lenses, extension of each time lens, and the standard phase height are optimally designed as functions of the AWG bandwidth B

M
and the EOPM damage phase threshold

Γ

0

. By numerical simulations, a 16-slot input optical Gaussian pulse sequence with half pulse width of 10 ps and frame length of 2000 ps is encrypted with a KS near

2

698

provided by ATLs at parameters

B
M

=

100

GHz and

Γ

0

=

5

π

radians under the state of the art, enough for resistance to brute-force attacks.
Did nuclear transformations inside Earth form nitrogen, oxygen, and water?
Authors: Fukuhara Mikio
Published: August 2020

Nitrogen and sea water concentrations have increased continuously from the Archean era. A rapid rise in oxygen concentration has been recorded from around 0.8 billion years ago. These phenomena cannot be completely explained by the collision of planetesimals with abundant nitrogen and the late veneer heavy bombardment of comets and meteorites with abundant water, and photosynthesis of heterotrophic plants, respectively. The formation of nitrogen, oxygen, and water are postulated to be the result of an endothermic nuclear transformation of carbon and oxygen nuclei confined in the carbonate aragonite lattice of Earth’s mantle or crust at high temperatures and pressures. This process was likely influenced by excited electrons generated by stick sliding during the evolution of supercontinents, mantle convection triggered by collisions of major asteroids, and nuclear fusion in Earth’s core. Thus, we show that calcium carbonates may have played a crucial role in the generation of atmosphere and sea water in Earth’s history.
Generation of non-thermal plasmas over large and complex surfaces
Authors: Jakob Henrike , Kim Min Kwan
Published: August 2020

Atmospheric non-thermal plasma is gaining increasing attention for various applications including food, medical and healthcare technologies because of its unique capability in producing reactive species. In spite of its promising potential, generating non-thermal plasma over large and complex geometries such as the human body or a narrow channel is still challenging and is limiting the use of atmospheric non-thermal plasma. In this study, we propose two new electrode systems, printed and knitted electrodes, to enhance scalability and flexibility of a conventional atmospheric non-thermal plasma source. The flexibilities of both electrode systems are quantified for varying curvatures to generate non-thermal plasma over complex geometries. Moreover, both electrode systems are assessed for varying system size to assess the ability of large scale plasma geometries. Electrical and optical diagnostics including Optical Emission Spectroscopy (OES), are used to monitor the property of plasma generated by these systems. The present study shows that both printed and knitted electrodes can produce non-thermal plasma, however both have certain limitations. Concluding from these findings, a schematic of new hybrid electrode system for the treatment of large surfaces or narrow long channels is proposed to eradicate these limitations.
Existence of exceptional points for Fuchsian groups of finite coarea
Authors: Nakanishi Toshihiro , Ushijima Akira
Published: August 2020

It is shown by Fera that there exists uncountably many exceptional points for cocompact Fuchsian groups. We generalize this result to the case that Fuchsian groups are of finite coarea.
Convergence analysis for a stabilized linear semi-implicit numerical scheme for the nonlocal Cahn–Hilliard equation
Authors: Li Xiao , Qiao Zhonghua , Wang Cheng
Published: August 2020

In this paper, we provide a detailed convergence analysis for a first order stabilized linear semi-implicit numerical scheme for the nonlocal Cahn–Hilliard equation, which follows from consistency and stability estimates for the numerical error function. Due to the complicated form of the nonlinear term, we adopt the discrete

H

−
1

H^{-1}

norm for the error function to establish the convergence result. In addition, the energy stability obtained by Du et al., [J. Comput. Phys. 363 (2018), pp. 39–54] requires an assumption on the uniform

ℓ
∞

\ell ^\infty

bound of the numerical solution, and such a bound is figured out in this paper by conducting the higher order consistency analysis. Taking the view that the numerical solution is indeed the exact solution with a perturbation, the error function is

ℓ
∞

\ell ^\infty

bounded uniformly under a loose constraint of the time step size, which then leads to the uniform maximum-norm bound of the numerical solution.
A countable dense homogeneous topological vector space is a Baire space
Authors: Dobrowolski Tadeusz , Krupski Mikołaj , Marciszewski Witold
Published: August 2020

We prove that every homogeneous countable dense homogeneous topological space containing a copy of the Cantor set is a Baire space. In particular, every countable dense homogeneous topological vector space is a Baire space. It follows that, for any nondiscrete metrizable space

X
X

, the function space

C
p

(
X
)

C_p(X)

is not countable dense homogeneous. This answers a question posed recently by R. Hernández-Gutiérrez. We also conclude that, for any infinite-dimensional Banach space

E
E

(dual Banach space

E
∗

E^\ast

), the space

E
E

equipped with the weak topology (

E
∗

E^\ast

with the weak

∗

^\ast

topology) is not countable dense homogeneous. We generalize some results of Hrušák, Zamora Avilés, and Hernández-Gutiérrez concerning countable dense homogeneous products.
Dynamics of Tpm1.8 domains on actin filaments with single-molecule resolution
Authors: Bareja Ilina , Wioland Hugo , Janco Miro , Nicovich Philip R. , Jégou Antoine , Romet-Lemonne Guillaume , Walsh James , Böcking Till
Published: August 2020

Characterization of the kinetics of Tpm1.8 binding to actin filaments with single-molecule resolution. This work provides molecular insight into actin–tropomyosin filament formation and the role of tropomyosins in regulating actin filament dynamics.