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Eldar M. Salpagarov, Andrey A. Belyakov, Aleksei V. Sivenkov
Materials Science Forum, Volume 1040, pp 68-74;

The main purpose of this work is to study and evaluate the mechanical properties of nanocomposite coatings based on metal-ceramics. The research also estimates factors affecting the unique properties of these surface coatings. The study compares the physical and mechanical properties of tool material plates with a nanodispersed multilayer composite coating and analyzes the results of mechanical tests with and without these coverings. The results of the investigation show that nanocomposite coatings contribute to hardness, strength and wear resistance more than three times, while traditional hardening methods, such as thermal and chemical-thermal treatment, improve the mechanical properties much less. It can be concluded that nanocomposite coatings can increase the strength resource of the tool. Their main disadvantage is the individuality of the properties of each coating and the need for expensive equipment for their creation and application. In the use of nanocomposite coatings to increase surface properties, multicomponent coatings are of the greatest interest. As a result of this work, the nanocomposite metal coating of the nc-TiN/a-Si3N4 system was studied, the dependence of properties on the content of the nc-TiN and a-Si3N4 phases was examined, and the optimal ratio was found which ensured the highest values of hardness with the best wear resistance.
K.G. Karapetyan, Olga V. Denisova
Materials Science Forum, Volume 1040, pp 41-46;

The paper considers the applications of foamed glassy phosphate materials as carriers of biologically active substances. One of the advantages of phosphate materials is their ability to effectively support the life of microorganisms. This feature of phosphate glassy materials opens up the prospects for the application of microorganism strains - destructors of oil products to their foamed samples, that is, the creation of biosorbents for purification of water and soil from hydrocarbon contamination. The advantages of a biosorbent are explained by the high biological activity of microorganisms on the surface of foamed glassy phosphates and the possibility of active development of microorganisms with the simultaneous destruction of petrochemical contaminants. The use of biosorbent eliminates the problem of its utilization and regeneration, thus it is suitable for repeated use. The formation of porous glassy phosphate materials on the surface by the method of molecular layering of monolayer coatings allows obtaining chemically modified composite materials, which improves their performance characteristics such as strengthening the material structure with a simultaneous increase in the catalytic activity of biochemical processes.
Pavel Dohnálek, Jaromír Jirkovský, Tereza Sázavská, Jan Šubrt, Václav Pumpr, Hana Bíbová, Michaela Jakubičková, Martin Pusztai
Advances in Science and Technology, Volume 108, pp 1-9;

This article presents research and development on innovative photoactive admixtures for concrete and cement-based plasters for the finishing of concrete surfaces finished this year. The goal of the development was to provide the resulting surfaces of these newly developed materials with a self-cleaning ability stemming from photocatalytic reaction during exposure to UV radiation. The specific function of all these products is based on the photocatalytic oxidative mineralization of all organic structures present on the surface, i.e., their gradual transformation into the final simple inorganic compounds, which are carbon dioxide, water and the corresponding mineral acids. This research and development was carried out as part of a project supported by the Czech Ministry of Industry and Trade, in the TRIO programme; and in cooperation of BETOSAN s.r.o., the Technical University of Liberec, the Institute of Inorganic Chemistry of the Czech Academy of Sciences and the J. Heyrovsky Institute of Physical Chemistry of the Czech Academy of Sciences. The first type of developed material is a photocatalytically active admixture in powder form, allowing the preparation of concrete surfaces with photocatalytic properties. The second type of developed material is a photocatalytically active cement-based plaster, intended primarily for application to a concrete substrate. Two final versions of both materials were developed. In the case of the plaster this means preparation of two colour variants, specifically white and grey. For the powder concrete admixture two types with different application procedures were developed. This means one version of admixture mixed throughout the entire volume of the concrete and second variant applied only in the surface layer of the concrete. We anticipate mainly exterior applications on the self-cleaning outer shell of buildings, as well as treatment of the surface layer of various structures such as bridges, noise barriers, traffic barriers and tunnels. The developed materials can also be used in interiors under specific conditions, with anticipated uses in the health care and food processing industries.
Diana T. Musina, Vadim R. Karibov, Ngo Q. Khanh
Materials Science Forum, Volume 1040, pp 94-100;

Stabilization of the functional properties of dispersed and compact solid metals, as well as regulation of their reactivity, improvement of water-repellent, antifriction and anti-corrosion properties by creating the protective films on the surface is an urgent problem of obtaining resource-saving materials. Previously, the research conducted at REC "Nanotechnology" of Mining University proved that chemisorption of ethylhydridesiloxane vapors together with cationic surfactants based on quaternary ammonium compounds has a beneficial effect on the water-repellent properties of metals. In order to obtain the physicochemical substantiation of the effect of hydrophobization of the surface of modified dispersed metals for the first time, the study of the electrophilic-nucleophilic properties of the active substances of the surface modifiers of dispersed and compact metals was carried out using the methods of quantum-chemical modeling in HyperChem software package. The dipole moment, energy of the highest occupied and the lowest unoccupied molecular orbitals, electrophilic-nucleophilic properties were determined. The series of enhancement of nucleophilic/electrophilic properties and dipole moment for modifiers were obtained. The donor-acceptor properties, the differences in the characteristics of the molecules of alkamone (A), triamone (T) and hydrophobic silicone organic liquid were quantitatively and qualitatively established. The patterns of the formation of hydrophobic properties of the surface during the layering of molecules of ammonium and organosilicon compounds with different electrophilic-nucleophilic properties on dispersed metals have been established. Recommendations for the use of modifiers for the production of high - and superhydrophobic materials are proposed.
Victor V. Nosov, Egor V. Grigoriev, Sabina A. Peretyatko, Artem P. Artyushchenko
Materials Science Forum, Volume 1040, pp 101-108;

The strength of materials is determined by their atomic molecular structure and the process of decay of atomic molecular bonds, which must be taken into account when optimizing materials strength control technologies. The fracture photomicrograph of metal microdamage of welded joint at various moments of time, a multilevel model of flow of acoustic emission signals of materials are presented. The physical meaning, the scale level of parameters included in the model are revealed. The structure of the mathematical model of the flow of AE signals with components of its informative elements of different scale level by strength characteristics of structural materials and resource of technical objects is shown. The multilevel model of the AE signal flow is hierarchically structured, obtained by generalizing deterministic-statistical variability. It describes the process of randomly recording deterministic accumulated damages in the material both before and after the formation of a crack at the stage of waiting for its next leap. It is shown that the proposed nanotechnology of strength control of materials is reduced to non-destructive determination of parameters of prognostic homogeneous destruction, identification of which is based on multilevel modeling of time dependence of micro-crack formation, formulation of criterion of strength homogeneity, registration of AE parameters related to the model of a specific product, which can be automated processing of registration results and determination of universal strength nanoconstants from already published reference data of fatigue tests of standard material samples.
Elena V. Zelenina, Vadim V. Bakhmetyev, , Mikhail A. Shvindin
Materials Science Forum, Volume 1040, pp 35-40;

Radioluminescence technologies are at the front line of the optic and electronic studies. Effective, self-contained and safe radioluminescent light sources can find their application in space industry, in medicine and in military technologies. The question of the performance improvement of the solid-state radioluminescent light sources (SRLS) without raising the included activity of working radionuclide can be solved by upgrading the phosphor crystalline structure. The electron-beam treatment for zinc-sulphide phosphors initial batch has been studied in a wide range of concentrations of the activating agent (Cu) for improving the radioluminescent performances of the phosphors, for creating the structural defects that form centers of luminescence. The changes of the phase composition were investigated under different synthesis conditions. It is revealed that electron-beam treatment of the initial batch leads to the growth of the wurtzite phase content in zinc-sulphide phosphors synthesized below the phase transition temperature. The changes of the phase content promote the spectral redistribution under the tritium beta-excitation. It is obviously the reflection of the fact of «green» luminescence centers rearrangement between the volume of the crystal and its surface. The correlations between structural configuration and performances of ionizing luminescence were found. Electron beam treatment gave the 20% increase of brightness of the radioluminescence. The achieved enhancement of luminescence performances allows the development of advanced tight-packed SRLS with minimal radioactivity and high energy-light conversion.
Valeria V. Strokova, Viktoriya V. Nelyubova, Ulyana N. Duhanina, Dmitriy A. Balitsky, Oleg I. Drozdov
Materials Science Forum, Volume 1040, pp 159-164;

The paper presents the results of the assessment of the effect of bacterial microorganism Sporosarcina pasteurii and CaCl2 and CH4N2O precursors as agents initiating carbonate mineralization processes on the construction and technical properties of binders. In order to achieve this, a preliminary bacterial solution with precursors was prepared, which was introduced into the system instead of mixing water in the range of 0–10% with interval of 2%. The effect of the bacterial solution as a complex additive on the physical and mechanical properties of cement paste and stone is shown: normal density, setting time, water segragation, strength in compression and bending. The introduction of the solution provides a reduction in the setting time of cement without loss of strength both at the initial and at the final stages of hardening.
P.Y. Piskarev, Alexander A. Gervash, S.A. Vologzhanina, Boris S. Ermakov, A.M. Kudryavceva
Materials Science Forum, Volume 1040, pp 8-14;

In this work, a study of the cases of destruction of the CuCrZr / 316L (N) bimetallic joint (BMJ) obtained by diffusion welding under conditions of hot isostatic pressing (HIP) was carried out. The identified defects are cracks propagating in the BMJ zone in the corner zone of the mock-ups of the heat-sink elements (HE). The analysis of the causes of destruction of the BMJ was carried out and the factors leading to the weakening of the BMJ zone are analyzed. The analysis of the thermal and stress-strain state of the HE mock-up during the manufacturing process was carried out. The study of the elements of the HE mock-up were carried out by methods of non-destructive testing (ultrasonic testing (UT)) and destructive testing (metallography; fractography; energy-dispersive X-ray spectroscopy; tensile tests). The inclusion of brittle phases in the zone of the BMJ was revealed and an assumption was made about the chemical composition of these phases. It was revealed that this line of brittle phases is a crack propagation zone in all cases of destruction of the BMJ in the HE mock-ups. The temperature range is revealed at which the effect of "ductility failure" of the CuCrZr is observed during the tensile testing of the samples.
Anna B. Vlasenko, Vadim V. Bakhmetyev, Sergey V. Mjakin
Materials Science Forum, Volume 1040, pp 61-67;

Photodynamic therapy (PDT) is a promising modern method for treatment of oncological, bacterial, fungal and viral diseases. However, its application is limited to diseases with superficial localization since the body tissues are not transparent for visible light. To address this problem and extend PDT application to abdominal diseases, an enhanced method of X-ray photodynamic therapy (XRPDT) is suggested, involving X-ray radiation easily penetrating the body tissues. The implementation of this approach requires the development of a pharmacological drug including a photosensitizer stimulated by visible light to yield active oxygen and a nanosized phosphor converting X-ray radiation into visible light with the wavelength required for the photosensitizer activation. This study is aimed at obtaining X-ray stimulated phosphors with nanosized particles suitable for XRPDT application. For this purpose, Y2O3:Eu phosphors were synthesized via hydrothermal processing of the corresponding mixed acetate followed by annealing. To prevent from the undesirable agglomeration of the particles in the course of hydrothermal synthesis and subsequent annealing, different techniques were used, including rapid thermal annealing (RTA), microwave annealing and addition of finely dispersed pyrogenic silica (aerosil) to the phosphor. The microwave annealing was carried out using a special installation including a resonance chamber for maintaining a standing wave of microwave radiation. The performed research allowed the determination of hydrothermal processing optimal duration affording the synthesis of phosphors with the highest luminescence brightness. The application of microwave annealing is found to provide phosphors with a more perfect crystal structure compared with RTA. The developed method of Y2O3:Eu phosphor synthesis involving pyrogenic silica addition to the autoclave allowed the preparation of samples with the amorphous structure and significantly reduced the particle size without a considerable decrease in the luminescence brightness. The particle size of the phosphor synthesized with aerosil addition is less than 100 nm that allows its implementation in pharmacological drugs for XRPDT.
Nikolay M. Barbin, Lydia V. Yakupova, Dmitriy I. Terentev, Valery T. Kuanyshev
Materials Science Forum, Volume 1040, pp 15-20;

The behavior of С56 fullerene when heated in a nitrogen atmosphere at a pressure of 105 Pa was studied using computer thermodynamic modeling. The modeling consisted in a complete thermodynamic analysis of the system using the TERRA software package, which is one of the most developed and efficient ones that implements such thermodynamic calculations. Experiment temperature ranges are from 273 to 3373 К. Based on the calculated data, a graph of the carbon balance in the С56-N2 system was constructed, the ongoing physicochemical processes were described, divided into four classes: sublimation, dissociation in the gas phase, chemical reactions occurring in the gas phase, dissociation and chemical reaction in the gas phase. Temperature intervals of reactions are identified. The equilibrium constants of the reactions are calculated and described, as well as the coefficients of these constants are found using the least squares method. The temperature interval of thermal stability of the condensed C56 fullerene and C56 vapors is defined. This work is one of the series of works on the properties of nanoparticles, in the future it is planned to study the thermal properties of higher fullerenes. The data obtained can be used to determine the explosive and fire hazardous properties of fullerenes as a dispersed solid.
Sergey V. Balabanov, Aleksei I. Makogon, Maxim Yu. Arsentev,
Materials Science Forum, Volume 1040, pp 185-190;

The article presents the results of a study of the physical and mechanical properties of cellular structures fabricated by means of additive manufacturing. The structural elements are repeating in three directions, and have a geometric shape of Schwarz-P surface. Samples in the form of a cube (size 30x30x30 mm) were created by layer-by-layer fusion of thermoplastic polymer on a FDM (Fused Deposition Modeling) 3D printer. Compression tests of samples with different geometry have shown that with an increase in the characteristic size of a repeating structural element with a decrease in the parameter (t), the strength of the samples increases and is maximal at t = -0.6. According to the calculations performed by the finite element method, this is associated with an increase in the area of ​​the dangerous section. However, specimens with t = 0 have the highest specific strength. This is because the average curvature of products with t = 0 is zero at each point, which contributes to the effective distribution of mechanical stresses in the specimen. When t ≠ 0, the average curvature is constant, but has a non-zero value.
Andrey S. Dolgin, Aleksei I. Makogon, Sergey P. Bogdanov
Materials Science Forum, Volume 1040, pp 178-184;

Today 3D printing with ceramics is a promising direction in the development of additive technologies. In this work, we have developed a technology for printing with ceramic pastes based on aluminum oxide and wax, namely: an extruder for printing with ceramic pastes was modeled and manufactured, the composition of the slip was selected and the paste for printing was made. After choosing the print parameters, test samples were printed: a disk and a box. Since 3D printing with ceramics is just one of the stages of manufacturing ceramic products, then we selected the parameters for drying and sintering the raw material. Drying of products is necessary to burn off an excess amount of a binder (paraffin), and due to sintering; the raw material acquires final strength and mechanical characteristics. After sintering, the sintering parameters and physical and mechanical properties of the products were measured. The microstructure of the printed products was studied using scanning electron microscopy. The phase change during sintering was studied by X-ray analysis. All obtained properties were compared with a reference sample (corundum tile made of aluminum oxide of the same grade, but using traditional ceramic technology, including pressing, drying and sintering of the product). In terms of all properties, the printed ceramics are not significantly inferior to the reference sample; however, in general, the additive technology has more advantages, such as a wide variety of shapes, shorter manufacturing time for parts, and lower energy costs.
Liana Yu. Saubanova, Semen V. Diachenko, Valeriya S. Loray, Liubov A. Nefedova, Sergey P. Bogdanov, Nikolay A. Khristiuk,
Materials Science Forum, Volume 1040, pp 172-177;

Powders of X6CrNiTi18-10 stainless steel were fabricated from original workpieces of different grade by gas atomization method. It was found that it is necessary to use argon as a gas for gas atomization of X6CrNiTi18-10 steel, since the use of nitrogen leads to the formation of its compounds, namely, titanium nitride. It is shown that all used workpieces – electric arc, electric slag and vacuum arc refinement – allow one to obtain powders suitable for further utilization in selective laser melting technology of 3D printing. The main physicochemical and technological properties of the obtained powders have been investigated. Changes in the chemical composition and quality of the powders are not significant within the X6CrNiTi18-10 grade. The 0...20 μm fraction of powders does not have fluidity, and thus cannot be used for additive technologies. The fraction 20...63 μm have suitable rheological properties for additive technologies and may be used in selective laser melting (SLM) process. The yield of target fraction 20 ... 63 microns was ≈45%. The fraction 63...120 μm may be used for the direct metal deposition (DMD) additive technology. Considering the economic aspect of the technology, it is preferable to use original workpieces of X6CrNiTi18-10 steel produced by electric arc or electroslag process, since the market price of vacuum arc steel is significantly higher. The fraction of ferrite phase in the powder increases with a decrease of particle size of the resulting powder and is lower comparing to the original workpiece. In the future, for a detailed study of the technological properties, it is planned to grow samples from each type of the obtained powders on installation for selective laser melting and direct laser deposition to determine the physical and mechanical properties of fabricated samples (tensile and impact bending tests) and carry out metallographic studies.
Milan Holický,
Advances in Science and Technology, Volume 108, pp 53-57;

Categorization of bridge constructions by the failure consequences due to loss of ultimate capacity or serviceability is a difficult task that can be resolved using two different approaches: elementary method using currently valid standards advanced method based on risk assessment. The elementary method is grounded on subjective assessment of bridge malfunctioning or collapse. The bridge is classified into an appropriate category (consequence class) in accordance with the most severe consequence. It is a simple procedure that may be applied without the need of demanding mathematical procedures. However, the resulting categorization may be affected by uncertainties in the assessment of consequences. The advanced method is based on a comprehensive analysis of bridge malfunctioning using a procedure of risk assessment. This method takes account of the occurrence probability of unfavourable events and the significance of individual consequences. Classification of a bridge construction into an appropriate category depends on the resulting risk of the bridge failure. This more laborious approach provides credible results without excessive uncertainties. The most adverse difficulty of the method is a combination of some consequences like the loss of life and economic costs. Both the above-mentioned approaches to the categorization of bridges by failure consequences can be effectively used depending on the type of bridge, on the intensity of exploitation, on expected consequences, and on social impacts of bridge malfunctioning.
Daria Dmitrievna Netsvet, Alexandr L. Popov, Viktoriya Viktorovna Nelubova, Svetlana V. Lasunova
Materials Science Forum, Volume 1040, pp 132-138;

The paper presents studies on the properties of various types of micro-reinforcing fibers to assess their role and effectiveness in the structure formation of the cellular composite. Based on the data on the weight loss after exposure in a model medium of cement, analysis of the alkali resistance of fibers of five different types – basalt fiber, heat-treated basalt fiber, polymer fiber and glass fibers from two different manufacturers – was carried out. It is shown that the fibers have a sufficiently high durability in the medium of hardening cement, which is expressed by a relatively insignificant weight loss of the original fiber after exposure in a model medium for 28 days in ambient conditions. The weight loss for some fibers sharply increases when hardening conditions are changed to hydrothermal ones. The images of fibers exposed in a model medium of cement, obtained using scanning microscopy, were also analyzed, and the character of distribution of acidic and basic adsorption sites on the surface of fibers depending on the type was assessed. Based on the analysis of the obtained data, we can talk about a high number of active sites on the surface of basalt and glass fibers, which ensures the formation of crystalline new formations on them and makes it possible to predict their high adhesion to the cement matrix.
Victor I. Bolobov, Stanislav A. Chupin, Erik V. Akhmerov, Vyacheslav A. Plaschinskiy
Materials Science Forum, Volume 1040, pp 117-123;

The results of tests for resistance to abrasive wear on highly abrasive hard rock white electrocorundum are presented. The main material of fast-wearing elements of mining and processing equipment-110G13L steel (Gadfield steel) in comparison with other 9 grades of steel and cast iron, including specially developed wear-resistant foreign steels such as Hardox and Miiluks, is analyzed. The studies were carried out using an experimental stand for studying the material wearing process. On the stand the sample was fixed in a holding device and, after being brought into contact with the abrasive, it was rotated under a constant load. As a result of the experiments, it was confirmed that the order of placement of the tested materials in terms of increasing wear resistance coincides with their placement in terms of increasing hardness. At the same time, the wear resistance of the most resistant material – U8A steel after quenching – is about 4 times higher than this indicator for the least resistant components – low-carbon steel 25L, including gray and high-strength cast iron SCH21, VCH35. The wear resistance of 110G13L steel, as well as 65G, U8 steels in the hardened state, is from 1.5 to 2 times higher than that of foreign steels M400, H450, M500, H500. The results of the conducted studies allow us to evaluate the analyzed materials on the basis of their wear resistance and hardness indicators on the feasibility of using them in the manufacture of fast-wearing parts of mining equipment. Based on the research data, it seems promising to develop new ways to increase the wear resistance of domestic steel, including 110G13L steel traditionally used in mining.
Karen Yu. Shakhnazarov, Evgenii I. Pryakhin, Andrey V. Mikhailov
Materials Science Forum, Volume 1040, pp 191-199;

The article deals with the problems of withstanding harsh temperatures by steel and iron. The authors of the work discuss iron denser high-temperature of γ modification and maximums and minimums of impact. In addition, the article analyses the transformations of iron and anomalies of properties: peak of heat capacity, acceleration of diffusion, etc. The authors take into account the consensus on the causes of polymorphism and the theoretical model of ferromagnetism. Besides, there is a consideration of "transformation" in interaction between Fe atoms that produce anomalies of steel properties. It is necessary to note the transformation detected by anomalies of any properties including mechanical. In the presented work the authors have made an attempt to prove transformations in iron at ~650 °C on the basis of extreme values of hardness and microhardness, metallographic structure, parameters of fine structure, precipitation resistance force depending on temperature. Therefore, the analysis of literature sources on physical and mechanical properties of iron and its derivatives has been made.
Ljubov Aleksandrovna Bokhoeva, I.O. Bobarika, A.B. Baldanov, Vitaly Evdokimovich Rogov, Anna S. Chermoshentseva
Materials Science Forum, Volume 1040, pp 124-131;

Due to the intensive development of composite materials and technologies for producing parts from them, they are increasingly used in various industries, including the manufacture of products with increased requirements for the characteristics of final products (strength, stiffness, minimum weight, etc.). In this regard, the authors analyzed the possibility to optimize the layered structure of a composite material in order to give it a pronounced predictable anisotropy of properties required for the final product. Thus, the influence of the orientation of the fibers of the reinforcing material in different layers of the package and the number of layers of the package on the physical and mechanical characteristics of the hypothetical product were analyzed. The problem was solved through the example of the development of a wing for a hypothetical UAV.
V.Yu. Piirainen, A.A. Barinkova, V.N. Starovoytov, V.M. Barinkov
Materials Science Forum, Volume 1040, pp 109-116;

Current global environmental challenges and, above all, global warming associated with a change in the carbon balance in the atmosphere has led to the need for urgent and rapid search for ways to reduce greenhouse gas emissions into the atmosphere, which primarily include carbon dioxide as a by-product of human activity and technological progress. One of these ways is the creation of industries with a complete cycle of turnover of carbon dioxide. Aluminum is the most sought-after nonferrous metal in the world, but its production is not environmentally safe, so it constantly requires the development of knowledge-intensive technologies to improve the technological process of cleaning and disposal of production waste, primarily harmful emissions into the atmosphere. Another environmental problem related to aluminum production is the formation and accumulation in mud lagoon of huge amounts of so-called highly alkaline "red mud," which is a waste product of natural bauxite raw material processing into alumina - the feedstock for aluminum production. Commonly known resources and technological methods of neutralizing red mud and working with it as ore materials for further extraction of useful components are still not used because of their low productivity and cost-effectiveness. This article describes the negative impact of waste in the form of "red" mud and carbon dioxide of primary aluminum production on the environment. The results showed that thanks to carbonization of red mud using carbon dioxide, it is possible to achieve rapid curing and its compact formation for safer transportation and storage until further use. Strength tests of concrete samples filled with deactivated red mud were also carried out, which showed the prospects of using concrete with magnesia binder.
Aleksei D. Khalimonenko, E.G. Zlotnikov, Ilya V. Gorshkov, M.A. Popov
Materials Science Forum, Volume 1040, pp 21-27;

The article deals with the determination of the efficiency of a multi-bladed tool equipped with inserts made of oxide-carbide cutting ceramics, depending on the microstructural parameters of the tool material. The microstructural parameters of the oxide-carbide cutting ceramic, which affect the performance of the tool, are proposed to be determined according to the electrical resistance of the tool material. In order to implement the method for determining the working capacity of the instrument, a basic design of the device for measuring the electrical resistance of the material of the instrument is proposed. The device for measuring the electrical resistance of ceramic plates consists of a body made of a dielectric material, with channels for supplying a conductive material and a groove for installing a case with a test sample. During the test, the channels are filled with a liquid conductive material, which fills the cavity formed by the channel of the case, the groove of the case and the plate itself under test. To ensure uniform filling of the cavity, after the introduction of the liquid conductive material, metal balls are installed into the channels, which are made in such a size as to ensure free sliding along the channel, but not to let the liquid pass into the upper part of the channel. The tested ceramic plate is installed in the walls of the removable case. The walls of the removable case include electrodes, which, when the device is in operation, are inserted into a cavity with a liquid conductive material at one end, and are connected to an ohmmeter at the other. Using a device for measuring the electrical resistance of ceramic plates, it is possible to determine the operability of the tool and guarantee its operation without rejection for a certain period of time, which was confirmed by experimental research in the milling of workpieces of machine parts made of gray cast iron. Experimental studies in multi-edge machining with cutters with different values ​​of electrical resistance of ceramic plates made it possible to plot graphs of the dependence of the quality of machining during milling on the operability of the tool and on the time of the machining process.
E.I. Pryakhin, A.E. Ligachev, Yurii R. Kolobov, Eugeny A. Zakharenko, Valeriy V. Romanov
Materials Science Forum, Volume 1040, pp 47-54;

This work represents the characterization of materials surface before and after laser processing with macrophotography, optical metallography, and scanning electron microscopy before and after thermal exposure. The factors influencing the reliability of the laser-induced code readability have been determined as color and contrast. The range of stability of the code readability under thermal influence on the structural materials under study was determined, which allows improving the reliability of the laser-induced marking codes readability. The research objects in this paper were samples of the following materials: alloys based on copper, aluminum, and iron with laser-induced codes of various types applied on the surface. This work aimed to research the stability of laser-induced codes readability after thermal exposure using macrophotography, optical metallography and scanning electron microscopy on structural materials of various purposes before and after laser processing (when forming a binary matrix code). The research results obtained and presented in this article on the stability of laser-induced codes reading under thermal action on structural materials can be used in different fields of industry, when marking products of heavy, general, medium, and precision engineering, as well as for marking metal products and blank parts. The results of this research are also planned to be used for further analysis of the occurring damage, leading to reading errors due to mechanical and chemical influences. It is planned to evaluate the limit values of the parameters that determine the degree of degradation at which the encoding will be considered to have lost the recognizing ability. Requirements for the quality and permissible code damage will also be developed to ensure their reliable identification.
Anna N. Popova, Viktoriia E. Kison, Vladimir S. Sukhomlinov, Alexandr S. Mustafaev
Materials Science Forum, Volume 1040, pp 87-93;

This paper presents the results of the application of new unique techniques based on plasma nanotechnology in metallurgy and materials science. In recent years, a team of authors have developed the solutions for extraordinary problems arising in the conditions of metallurgical enterprises related to the production of synthetic materials and control of manufactured products, namely, the methods for the production of various structural materials and optimization of methods for their non-destructive testing by atomic emission spectral analysis (AESA). The paper points out some aspects of ongoing research, in particular, an innovative technique that allows obtaining ultrapure samples of white corundum by plasma melting of alumina in a reactor. This method also allows obtaining ultrapure aluminum at the output, which can be used for the purposes of hydrogen energy. In the course of the research, the criteria for thermal protection, temperature conditions and optimal parameters of the plasmatron were determined. In order to carry out the studies of metals and alloys by AESA method, a new global analytical method was developed, which made it possible to take into account the influence of various important parameters, including third elements, background plasma radiation, etc. This method has been preliminary tested on emission spectrometers made in Russia and can significantly reduce the error in the determination of low concentrations of elements. In addition to the consideration of these parameters, the method makes it possible to perform high-precision calibration of atomic emission spectrometers of the same type (produced in series), using not a set of several tens of approved standard samples, but only two standard samples. For each area, patent applications were formed and filed.
S.B. Ermakov, S.A. Vologzhanina, Boris S. Ermakov
Materials Science Forum, Volume 1040, pp 1-7;

New requirements put forward to the modern industry to reduce harmful emissions increase the utilization rate of metal, reduce the production time of equipment, the production of components and parts from hard-to-process materials aim to introduce new technological processes. A promising technology is additive growing, which allows one to minimize the production time of unique products, to use hard-to-process alloys, for example, based on the Ni-Fe-Cr system, in their manufacture. The study was carried out by the method of mathematical planning of the experiment with subsequent processing of the results on a supercomputer. The results of the influence of the current applied to the plasma torch and the flow rate of the plasma-forming gas are presented; wire feed rates during spraying in power plants per fraction and particle size ratio in the volume of the yield of suitable. The minimum allowable yield of the product is set at 30 % with the production of fractions in the range from 40 to 140 microns. The results obtained for the Inconel 718 alloy confirmed the possibility of obtaining Ni-Cr-Fe alloy powders. The mode proposed in the work allows obtaining commodity fractions at the level of 30-35% of the mass of the sprayed feedstock. Additional tests of the mechanical properties and corrosion resistance of samples made from the resulting powder showed satisfactory results, similar to the results of tests of samples made from heat-treated alloy forgings.
Tomáš Zelenka
Advances in Science and Technology, Volume 108, pp 17-22;

The article deals with the construction of a geophysical observatory in the town of Fürstenfeldbruck, Bavaria, Germany. The observatory is being built for the Technical university in Munich. The main function of the observatory is to measure changes in the Earth ́s spin rate or, its axes deviations etc., which can occur with physical impulses in a form of, for example, an earthquake or nuclear explosion etc. Measuring such physical phenomena is important and the data is used to adjust navigation of satellites orbiting the Earth. As there were installed unique measuring tools in the building, the construction materials and building process itself has had to be carefully chosen and though through. The observatory is placed underground and has shape of a tetrahedron. The top of the construction is oriented in direction to the Earth ́s centre. To secure the pit the sprayed shotcrete was used and reinforced with AR Glass. To anchor the pit horizontally they also used the AR Glass. After finishing the pit, the central shaft was built and situated vertically from the top of the tetrahedron in direction to the Earth ́s surface and to the top of the tetrahedron base. Under a layer of concrete, there is a PE HD pipe DN 630 in every wall to connect the tetrahedron top with the base tops. There are several concrete shafts situated in each top tetrahedron base and also, at half of the span between the tetrahedron base tops. All these concrete shafts on the ground are interconnected by plinth beam with one another. The plinth beam contains three PE HD pipes DN 140. This type of construction was chosen as there is laser circling in the tetrahedron base, its top, and between tetrahedron top and base. In every shaft there is installed a measuring instrument, which is very sensible when in contact with steel parts. The sensibility to steel was a reason for employing only glass reinforcement GFK in every concrete part of this construction.
Valeria V. Strokova, Maria V. Nikulina, Pavel S. Baskakov, Alina V. Abzalilova, Anastasia Y. Esina
Materials Science Forum, Volume 1040, pp 165-171;

The existing methods of confering hydrophobic properties to various building materials are considered. Obtaining special, including hydrophobic, properties of water-emulsion paints is a very relevant task. Previously, a method was developed for producing an emulsion of a polysiloxane stabilized with polyvinyl alcohol. The paper describes the possibility of using a hydrophobisating emulsion of polyhydrosiloxane as a functional additive for an acrylic water-dispersion paint. This emulsion is capable of forming coatings on dense and porous surfaces with an adjustable contact angle up to 105 °. The use of this emulsion, with its sufficient coalescence for volumetric hydrophobization of coatings, makes it possible to obtain a high contact angle on the surface. In the paper, it was assumed that the partial introduction of small amounts (up to 10 %) of a hydrophobizing emulsion into water-dispersion paints would allow achieving the contact angle of wetting for similar coatings consisting exclusively of emulsion. It is shown that the introduction of small amounts of a hydrophobizing emulsion with an auxiliary coalescing action of ethylene glycol makes it possible to impart hydrophobic properties to the surface of the resulting coating. When the optimum concentration of ethylene glycol in the coating is reached, dissolution and transport (yield) of polysiloxane to the surface is ensured. The research carried out made it possible to develop a paint composition with a hydrophobizing emulsion with a contact wetting angle of about 100 °, which ensured the hydrophobicity of the previously hydrophilic coating of a water-dispersion acrylic paint.
, Petr Bíly, Radek Štefan
Advances in Science and Technology, Volume 108, pp 35-44;

Nowadays, the safety of nuclear power plants is of increasing interest and importance. The main reasons for increased safety concerns are the recent major nuclear accident in Fukushima in 2011 and the overall tendency of environment protection. One of the possible ways of increasing the safety of nuclear power plants is the underground placement of all potentially dangerous systems under ground as the overlying soil or rock layer would act as a "earth" containment which would reduce the probability of ground level release following primary and secondary containment failure. Moreover, partial or total underground placement of nuclear power plant would reduce its visibility, and thus, public concerns would also be reduced. However, many design, operational, and economic disadvantages are linked with the underground placement of nuclear power plants. The aim of this paper is to provide state-of-the-art review of existing underground nuclear reactors, conceptual designs of underground nuclear reactors, and related literature, which can later be used for the design of a underground reinforced concrete containment building.
Anastasiia M. Dorokhina, Vadim V. Bakhmetyev, , Hiroko Kominami, Arira Fujii
Materials Science Forum, Volume 1040, pp 55-60;

In this paper, the time effect of hydrothermal synthesis on YF3 morphology particles is considered. The work was carried out on X-ray-excited YF3:Ce3+ phosphors. The synthesis was carried out by the hydrothermal method, since it avoids high temperatures leading to particle agglomeration. The first stage of research consisted in identifying the most favorable medium for obtaining the required phase and size - water or organic matter (ethylene glycol and ethanol). Research has shown that ethylene glycol has all the advantages: it prevents agglomeration, allows us to get the required phase. Hydrothermal synthesis of YF3 samples to determine the optimal synthesis time was carried out according to the same scheme - in an organic medium of ethylene glycol without using stabilizers for 4, 8, 12, 16, 20 hours. Our study showed that it is possible to obtain a YF3 sample that meets the necessary requirements (including nanoscale) within 16 hours, moreover, without the use of stabilizers. In parallel with the study of the synthesis duration, an experiment was carried out on the effect of various stabilizers on the properties of the YF3:Ce3+ phosphors (5%). The synthesized nanophosphors possessed effective X-ray luminescence with a maximum in the region of 300 nm, which makes it possible to use them in the composition of preparations for PDT.
Vladimir V. Tomaev, Andrey G. Syrkov, , Vladimir V. Taraban
Materials Science Forum, Volume 1040, pp 75-86;

The scientific basis for the production of a new composite material (1-x)PbSexPbSeO3, where x=0-1, by oxidation with oxygen at temperatures of 500-550 °C and oxidation times of 0.5-4 h from the initial phase of PbSe in the form of powder, film or compact material, having a ferroelectric phase transition in disordered crystals is developed. On the X-ray spectra of the original PbSe samples oxidized at 500°C (oxidation time of 0.5 h) it has been found that the PbSe phase reflexes are predominately present, including the X-ray spectra of the original PbSe samples oxidized at 500 °C (oxidation time of 4 h) - PbSeO3 monoclinic phase reflexes. For all other PbSe oxygen-oxidized samples at temperatures of 500-550 °C and within the time range of 0.5-4 h, X-ray spectra show the simultaneous presence of X-ray reflexes of both phases with the trend of increasing the PbSeO3 phase as the oxidation time increases. Temperature measurements of the DC resistance of the PbSe samples revealed an abnormal change in electrical resistance at the initial oxidation stage for both the film and the compact material, and further oxidation contributed to the capsulation of PbSe grains by the dielectric casing PbSeO3 and the gradual increase in the resistance of the material.
Svetlana D. Pozhidaeva, Evgeniy G. Klikin
Materials Science Forum, Volume 1040, pp 28-34;

The search for optimal conditions for the method of synthesis of copper (II) salts to create a unified one-step method for obtaining salts from natural raw materials was the purpose of this work. During the process of salt production, it is desirable that the product accumulates in the solid phase and is easily separated by phase separation methods. The study of the direct interaction of copper (II) oxide with acids in organic liquid media using a bead mill as a reactor and grinding agent of different nature showed that besides the usual places of localization of product that take place in practice, we can meet unusual places of localization of product, such as the surface of a foreign solid phase in the reactor zone, for example, the surface of the grinding agent, reactor elements, etc. It was found that in some cases, localization on a solid surface could be a favorable localization option in terms of the speed of the process. But it happens not always, because it requires specific methods of separation of film from surface, which can be very expensive. Often, the localization of the product on the solid surfaces is an extremely unfavorable localization option. It was found that different variants of product localization of interaction CuO with acids which were implemented in different proportions, prevented the creation of a unified method for producing salts in such systems
, Radek Štefan
Advances in Science and Technology, Volume 108, pp 45-52;

In the last decade, the computing power of computers has significantly increased, which enabled very detailed and accurate numerical static non-linear analyses of reinforced concrete structures to be carried out using sophisticated commercial software. However, higher risk of errors, both in the calculation inputs and algorithm, is linked with the increased detail and accuracy of numerical modelling. For this reason, it is convenient to verify the results provided by sophisticated software using simplified analytical approaches. In order to provide a tool for quick and easy verification of results provided by sophisticated software, a novel web-based application employing simplified analytical methods has been developed by the authors of this paper. This web-based application is capable of quick and easy calculations of bending moments in reinforced concrete two-way slabs. For the calculation of bending moments, the Marcus Method is employed. This method introduces a correction coefficient to the Rankine-Grashoff Theory of Equal Deflections in order to account for the torsional restraints at the corners of the slab. These analytical methods are algorithmized and implemented using the JavaScript programming language. A graphical user interface for the input of data and for the interpretation of results is created using the HTML markup language. The novel web-based application is freely available and works on all common devices and operating systems. From the presented results, it is clear that the novel web-based application is quick, easily available, user-friendly, and intuitive. The web-based application can be used for the verification of the calculated bending moments during the design of a reinforced concrete two-way slab.
Yulia N. Ogurtsova, Valeria V. Strokova, Pei Qi Zhao, Marina V. Antonenko, Ekaterina N. Gubareva
Materials Science Forum, Volume 1040, pp 153-158;

The paper presents the results of the determination of the effect of a photocatalytic composite material (PCM) with the composition SiO2‒TiO2 on the main properties of white Portland cement: heat release during hydration, phase composition and microstructural features of cement stone, pressure strength and self-cleaning ability. PCM was synthesized by a sol-gel method based on tetrabutoxytitanium and finely dispersed diatomite powder and 15% cement was added instead. The presence of PCM in the cement system provided the reduction of the induction period of cement hydration, consolidation of the microstructure of the cement stone with the products of the pozzolanic reaction, the ability to photocatalytic self-cleaning of the cement stone surface.
Sergey P. Bogdanov, Nikolay A. Khristiuk, A.V. Anisimov,
Materials Science Forum, Volume 1040, pp 139-152;

The article presents the results of a study of diffusion chromium plating of stainless steel X20Cr13 by iodine transport. The main kinetic laws of the process - the effect of temperature and time of chromium plating on the thickness of the coatings - have been studied. It is shown that the main phases of the coating are chromium carbides and nitrides with surface microhardness HV up to 15 GPa. The tribotechnical properties of the obtained coatings on rollers - friction pairs are determined.
Mohamad Yasser Baaj
Advances in Science and Technology, Volume 108, pp 23-33;

Construction industry is one of the oldest industries in the world. It is the most manpower dependent industry in mankind civilization till now, very risky industry, and very slowly changing compared to other industries like IT hardware or car manufacturing for which a huge development took place to reduce, or may be eliminate, dependency on manpower.
Pavel Krupík
Advances in Science and Technology, Volume 108, pp 11-16;

Roads with cement concrete covers have a long tradition in the Czech Republic. They are used mainly on highway sections of roads with higher traffic intensity. The subject of this article is a brief description of communications with cement concrete cover. Furthermore, the determination of the expected time cycles of their maintenance and costs in the time axis of life from the perspective of Construction 4.0 and facility management. The article is based on TP 92 Design of maintenance and repairs of pavements with cement concrete cover [6]. The output is an interface in an Excel spreadsheet both in the current financial statement and in graphical form, which can serve as a basis for planning future repairs, including securing financial resources.
Jana Majerová, Rostislav Drochytka
Solid State Phenomena, Volume 321, pp 171-176;

The electrical conductivity of concrete can be achieved by adding steel wires or functional fillers. Commonly used fillers are nanotubes, carbon black, nickel powder and so on. These fillers are expensive, but there is a possibility to use waste materials. This is the subject of this experiment. The conductive properties of conductive sand, sludge from the wire drawing process, iron grinding dust waste and waste carbon were verified. From these fillers, waste carbon showed the best electrical properties (impedance). The impedance of the waste carbon was 0.31 Ω and the impedance of the cement composite containing 70% of the weight of waste carbon was less than 670 Ω.
Dorothea Sklenářová, , Diana Mária Koporcová
Solid State Phenomena, Volume 321, pp 45-50;

In this study, the process of decomposition of CaCO3 and crystallization of CaO has been analyzed. The aim of this work is to compare behavior and changes in microstructure between different limestone samples (as geological age and origin, total porosity, hardness category). Studied samples were analyzed in high temperature chamber during the firing process by XRD analysis. With the increasing temperature, the growth of crystallites was measured and computed. In multiple samples a different behavior in these properties was observed. Further analysis studied different temperatures of the end of decomposition of CaCO3 and the beginning of formation of CaO in soft-porous and hard-recrystallized limestones.
Michal Pešata, Lukáš Procházka, Jana Boháčová
Solid State Phenomena, Volume 321, pp 105-111;

This paper deals with the possibility of using pumice concrete as thermal insulation lining of industrial chimneys. Two formulas were prepared, the first from sulphate resistant cement and the second as a reference mixture from Cem I 42.5R. The thermal insulating properties of the prepared recipes will be evaluated as well as the resistance to the action of sulphates in 5 % sodium sulphate solution. No significant decrease in strength was observed when samples were stored in 5% sodium sulfate solution for 60 days. Only the reference series reported a significant unexpected decrease in strength.
Solid State Phenomena, Volume 321, pp 131-140;

Forsterite refractory ceramics is utilized in the metallurgical and cement industries as a lining of metallurgical furnaces and rotary kilns for its high refractoriness up to 1850°C and refractoriness under load above 1600°C. Another significant property of forsterite is its coefficient of linear thermal expansion utilized in the electrotechnical industry for ceramic-metal joints. Addition of aluminium oxide into the raw material mixture results in creation of magnesium-alumina spinel (MgO·Al2O3) which improves sintering, thermal shock resistance and mechanical properties in comparison with pure forsterite ceramics. Inexpensive source of aluminium oxide is fly ash. Utilization of fly ash, secondary energetic product of coal-burning power plants, is important for the environment and sustainable development. This paper evaluated properties of fly ash-based forsterite-spinel ceramics in comparison with alumina-based forsterite-spinel ceramics. Forsterite-spinel ceramics was synthesized from olivine, calcined magnesite and fly ash/alumina powders. XRD analysis was used to determine mineralogical composition, thermal analyses were used to determine the behaviour during firing and scanning electron microscopy to determine the morphology of crystal phases. Refractoriness of pyrometric cones, refractoriness under load, thermal shock resistance, coefficient of linear thermal expansion, water absorption, porosity and modulus of rupture were also determined on fired test samples.
Solid State Phenomena, Volume 321, pp 73-79;

Stability of microstructure and heat resistant ability at high temperature is one of the important properties in ceramics or silicate materials which are normally exposed with fire such as refractories and insulation or other materials used in furnaces. This study used a ternary-blended geopolymer which was synthesized from an optimized mixture of red mud (RM), rice husk ash (RHA), diatomaceous earth (DE), and water glass solution (WGS) with silica modulus of 2.5. The geopolymer samples were tested thermal properties of heat resistance (%), volumetric shrinkage (%), mass loss (%) at 1000°C to evaluate thermal resistant ability. Changes of microstructure of the ternary-blended geopolymer samples were also characterized before and after exposed at high temperature using methods of X-ray diffraction (XRD), Thermogravimetric analysis or thermal gravimetric analysis (DTA-TGA), and Scanning electron microscope (SEM). The experimental results showed the ternary-blended geopolymer has high thermal stability and unchanged microstructure even at high temperatures. Hence, the geopolymer in this study is suggested to apply as an insolation with the upper limit of temperature to work at 1000°C.
Petr Figala, Rostislav Drochytka, Vit Černý
Solid State Phenomena, Volume 321, pp 37-42;

This work deals with the basic research and development of new technologies of cement-based invert grouting, in the recipe of which the appropriately selected secondary raw materials will be used as much as possible. This new grout will be part of a new comprehensive system for the remediation of chemically exposed building structures, such as sewers, silage pits and wastewater treatment plants. The aim of this work is to monitor the influence of the method and the degree of homogenization of the developed recipes on selected physical-mechanical properties of the injection material. For the needs of this work, several basic recipes were proposed, as well as the methodology of production of test specimens, their storage and testing. At the same time, three homogenization methods were chosen, differing in the manner and degree of implementation. The basic characteristics of grouting materials, which were monitored in this work, include the viscosity and processability of fresh material. Due to the requirement for increased resistance of the new material, the compressive strength and absorbency of the hardened test specimens 40 × 40 × 160 mm were monitored depending on the maturation time. The research results so far show that thorough homogenization has a fundamental effect on achieving the required physical-mechanical properties. The final methodology of homogenization of dry components will be used in the pre-preparation of all materials of the new chemically resistant remediation system, including the sprayed mixture.
Lucia Osuská, Milan Meruňka, Rudolf Hela
Solid State Phenomena, Volume 321, pp 119-124;

For concrete constructions built as underground spaces, basements or cellars, it is necessary for these constructions to be able to resist the influence of groundwater pressure that could disrupt the compactness of the entire construction by its action. For this reason, constructions of so-called white boxes are often used. White boxes are concrete constructions whose main capability is high water impermeability, exhibiting at the same time minimal volume changes. These properties could be accomplished by a series of several technological precautions, one of which is the composition of the concrete mixture itself. The aim of this paper is to evaluate the influence of finely ground limestone and the latent hydraulic addition of finely ground blast furnace slag on the properties of concrete composite such as water impermeability, water absorption, or volume changes. These properties are vital for the construction of white boxes. In this paper, the suitability of the mutual combination of active and internal additive will also be evaluated.
, Phong Thanh Dang
Solid State Phenomena, Volume 321, pp 65-71;

Climate change is recognized as a global problem and even the industrial and construction sectors are trying to reduce the green-house gas emissions, especially on CO2 emissions. In Vietnam, the coal-fired thermal power plants are discharging millions of tons of CO2 and coal ash annually. This coal ash is comprised of about 80% of fly ash and the rest is bottom ash. This study would like to introduce one of the potential solutions in a carbon-constrained society that would not only manage the fly ash but also utilized this as raw material for green materials through geopolymerization. The geopolymer-based material has lower energy consumption, minimal CO2 emissions and lower production cost as it valorizes industrial waste. The fly ash containing high alumino-silicate resources from a coal-fired power plant in Vietnam was mixed with sodium silicate and sodium hydroxide solutions to obtain the geopolymeric pastes. The pastes were molded in 10x10x20cm molds and then cured at room temperature for 28 days. The 28-day geopolymer specimens were carried out to test for engineering properties such as compressive strength (MPa), volumetric weight (kg/m3), and water absorption (kg/m3). The microstructure analysis was also conducted for this eco-friendly materials using X ray diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), Differential Thermal Analysis - Thermal Gravimetric Analysis (DTA-TGA).
David Bujdoš
Solid State Phenomena, Volume 321, pp 83-87;

This paper deals with the comparison of non-destructive methods of measuring modulus of elasticity by ultrasonic pulse velocity method and impact resonance method. Main research is focused on scattering of measured data, where by different volunteers were used the methods mentioned above on same test sample. This paper does not deal with the conversion relationships between individual methods, but it outlines the suitability of the chosen method in participation with the nature of samples, the difficulty of measurement and the expected reproducibility and interpretability of the measured data.
Grigory Ivanovich Yakovlev, Ekaterina V. Begunova, Rostislav Drochytka, Jindřich Melichar, Igor Aleksandrovich Pudov, Zarina S. Saidova
Solid State Phenomena, Volume 321, pp 51-57;

The paper presents the results of studies of the structure and properties of a fluorohydrite binder modified by a chrysotile nanotubes dispersion in a medium of calcium nitrate solution. It is shown that addition of this modifier into the anhydrite composition leads to a 106-fold decrease in electrical resistance. Microstructural analysis of the fluorohydrite composition showed changes in the morphology of new formations with the creation of crystalline hydrates of increased density. The presence of elongated nanocrystals on the surface of the hardened matrix was noted. In addition, IR spectrum absorption lines, prove the presence of calcium nitrate in the pore space of the composition, which contributes to a significant decrease in the electrical resistance of the developed composite.
Martin Ťažký, Rudolf Hela
Solid State Phenomena, Volume 321, pp 15-21;

The continuous tightening of emission limits for the production of harmful substances into the air and the rising price of emission allowances gradually force construction material producers to limit the use of binders with a high content of Portland clinker. In the production of concrete, this is achieved by using admixtures, which make it possible to reduce Portland cement doses. However, the single European market uses a method that maximises the use of blened cements, making it easier for cement plants to meet emission limits while not reducing cement production. The performed experiment focused on the possibility of using CEM II and CEM III cements and their comparison with CEM I cement not only in terms of the physical–mechanical parameters of concrete but also in terms of the stability of concrete mixtures made from these cements. The stability of concrete mixtures was monitored using the water separation value in the pressure method. In the experiment, the relationship between water separation and physical parameters of cement was explored.
Ondřej Pikna, Martin Ťažký, Rudolf Hela, Klára Křížová
Solid State Phenomena, Volume 321, pp 3-8;

One of the main characteristics in the concreting of massive waterproof structures and dam bodies is the prediction of crack formation. This prediction is associated with an understanding of the mechanics of development of hydration temperatures that affect in particular the selected binder parts of concrete. A suitable combination of cement with mineral admixtures, as well as the use of so-called shrinkage-reducing admixtures, seems to be an effective tool for influencing the dynamics of development and maximum values of hydration temperatures. Appropriate selection of the formula itself can significantly extend the lifetime of the mentioned structures. The paper is focused on monitoring the influence of different types of mineral admixtures on the effect of volume changes of cement pastes. The association of these volume changes with the development of hydration temperatures of these pastes was also observed. In order to minimize both of these phenomena, the possibility of using a shrinkage-reducing admixture was verified.
Lenka Nevřivová,
Solid State Phenomena, Volume 321, pp 149-155;

The mineral mullite has many outstanding refractory properties. The content of aluminum oxide in the raw material is the basic factor influencing the content of mullite in the final product. Depending on Al2O3 content, silica-alumina materials can be divided into fireclay and high-alumina with the Al2O3 content of 45 % and more. The study describes the influence of raw material, the influence of homogenization of raw material and influence of firing temperature on the mullite formation in fireclay refractory material. Three kinds of refractory clay with different chemical composition were used as raw material for fireclay grog production. Three kinds of homogenization and three different temperatures were studied as factors influencing mullite formation. Powder X-ray diffraction was used to determine mullite content in material. Quantitative phase analysis was conducted by the Rietveld method. Mullite crystals morphology was observed by scanning electron microscopy.
Jan Bubeník, Jiří Zach
Solid State Phenomena, Volume 321, pp 157-164;

Currently, the use of board materials as a material intended for the dry construction of building structure cladding in the building industry has become widespread. The most common types of board materials include wood-based boards (particle, fibre, laminated / plywood, oriented strand boards [OSB]), cement-bonded particleboards and gypsum plasterboards or gypsum fibre boards. In the case of board materials based on inorganic binders, these are most often represented by boards in which the fillers used are bonded by plaster or cement. Wood can then be used as filler, which is predominantly an assortment of inferior-quality trees or comes from a short rotation coppice, treated by various technological processes. Microstructure and material composition have the greatest influence on the physical and mechanical properties of the boards. The use of the boards in the internal or external environment is determined by their individual properties. Another indicator for the possible use of boards is the form of moisture with which the board comes into contact after installation into the structure. For the external environment, the boards have to withstand mainly liquid moisture; in contrast, in an internal environment, the boards come into contact mainly with air humidity. The diffusion properties of the individual products are also crucial for the overall design and use of the boards for structure cladding.
Pavlо Krivenko, Volodimir I. Gots, Oleh Petropavlovskyi, Igor Rudenko, Oleksandr Konstantynovskyi
Solid State Phenomena, Volume 321, pp 165-170;

Optimization of complex shrinkage-reducing additives (further, SRA’s), consisting of ordinary portland cement clinker (further, OPC clinker), salt-electrolyte and surfactants, is provided for prevention of steel reinforcement corrosion due to shrinkage mitigation in alkali-activated slag cement (further, AASC) fine concrete. Modification of AASC by SRA included 0.3 % sodium lignosulphonate, 0.15 % sodium gluconate, 1.4 – 2.0 % NaNO3 and 6.5 - 7.7 % OPC clinker (by mass of granulated blast furnace slag) provides shrinkage reduction from 0.984 up to 0.560 – 0.605 mm/m (t=202 °С, R.H.=65 %). Unlike, SRA presented by the mentioned system with 1.50 - 1.59 % Na2SO4 and 4.0 - 4.65 % OPC clinker causes shrinkage mitigation from down to 0.625 - 0.640 mm/m. In addition, SRA with 1.80 - 2.05 % Na3PO4 and 4.0 - 4.6 % OPC clinker minimizes shrinkage to 0.713 - 0.700 mm/m. Shrinkage mitigation in modified AASC fine concrete is explained by less water, higher crystallinity of hydrated phases as well as by formation of minamiit (Na,Ca0.5)Al3(SO4)2(OH)6, calcium hydronitroaluminate ЗСаО∙А12О3∙Са (NO3)2∙10Н2О and calcium hydroxylapatite Са10(РО4)6(ОН)2 crystals versus salt-electrolyte, i.e. Na2SO4, NaNO3 and Na3PO4 agreeably. The 28 day compressive strength of modified AASC fine concrete is not less than the reference one (48.0 - 56.0 МPа).
Sergii G. Guziy, Olena Guzii, Vasyl Lashchivskiy
Solid State Phenomena, Volume 321, pp 97-103;

Practical work and is devoted to the study of the rheological and deformative properties of Geofip aluminosilicate glue, obtained on the basis of an alkaline aluminosilicate binder composition Na2O Al2O3×6SiO2×20H2O, modified with 5% Cr2O3, when gluing wooden trusses in the field. The rheological and deformative properties of an aluminosilicate adhesive based on an alkaline aluminosilicate binder composition of Na2O×Al2O3×6SiO2×20H2O modified with 5% Cr2O3 have been investigated. It is noted that the dynamic viscosity of the adhesive slurry in the speed range from 0.1 to 0.8 RPM varies from 147600 to 144600 cP, and the average plastic viscosity in the same speed range is 87.39 cP. It was found that at shear rates from 0.021 to 0.168 1/s, an increase in shear force from 31 to 242.9 dyne/cm2 is observed due to the stabilization and uniformity of the dispersion phase particle distribution in the dispersion medium of the adhesive. It is shown that the aluminosilicate adhesive at a surface tension value of 88.1 mN/m is characterized by coefficients of wetting (s = 0.648) and fluidity (f = -62.02 mN/m), which ensures the uniformity of its application to the pine substrate. The average thickness of the adhesive layer was 1.25 mm, and the average depth of penetration of the aluminosilicate adhesive into the wood substrate, respectively, 0.12 mm. The destruction of the adhesive seam occurred at shear stresses of 515 MPa. The relative shear deformations were 162.5×10-5 mm.
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