Nanotechnologies in Construction: A Scientific Internet-Journal @nanobuild-en
Статьи журнала - Nanotechnologies in Construction: A Scientific Internet-Journal
Все статьи: 523
Creation of polymer composites with mineral fillers
Статья научная
Introduction. Currently, the development of science and technology requires the creation of new polymer composites with high technical characteristics for various industries. One of the primary methods to improve the physical and technical characteristics of polymer composites based on thermoplastic elastomers is by incorporation of natural fillers. In the Kyrgyz Republic, there is particular interest in using fine mineral fillers extracted from local natural resources. The minerals and rocks found in the region are characterized by high availability, extensive reserves, and a variety of properties. The accumulated experience in research and practical application opens up prospects for using these materials to create polymer composites with unique characteristics. This opens up new possibilities for using the cavitation process in various industrial applications, including the grinding of materials. Methods and materials. An experimental hydrocavitation mill has been developed to produce fine powders from minerals and rocks intended for use as fillers in polymer composites. The physicochemical properties of polymer composites and their raw materials were studied using modern instruments and equipment. The fractional composition and physical and technical characteristics of some minerals and rocks used to obtain active fillers for polymer composites are given. Results and Discussion. The fractional composition of crushed fillers with a particle size of less than 0.31 mm is distributed as follows: finely ground basalt – 7.3%, wollastonite – 44.6%, marble dust – 50.26%, brown coal powder – 47.56%. The analysis shows that among the studied fillers, finely ground basalt contains the smallest amount of fine fractions, which is due to its high hardness compared to other minerals such as wollastonite, marble, and coal. Physical and mechanical studies of the resulting polymer composites showed that when finely ground basalt is added, an uneven distribution of basalt powder in the polymer matrix is observed, which leads to a decrease in the strength characteristics of the composite. Therefore, to obtain a more durable material, it is necessary to grind minerals and rocks to the level of microparticles using the cavitation effect. For this purpose, a laboratory mill was created that operates based on the cavitation effect. Fillers at the level of micro- and nanoparticles were obtained using the developed hydro cavitation mill. The physical and technical characteristics of polymer composites with additives of the resulting nanofillers have been determined. The compressive strength of composites with mineral fillers (fraction less than 0.31 mm, content of wollastonite filler in the composite – 25.2%) was 5.47 MPa, with basalt filler – 5.2 MPa, and with leather powder (dust) – 4.25 MPa. Fillers at the level of micro- and nanoparticles were obtained using the developed hydro cavitation mill. The physical and technical characteristics of polymer composites with additives of the resulting nanofillers have been determined. The compressive strength of composites with mineral fillers (fraction less than 0.31 mm, content of wollastonite filler in the composite – 25.2%) was 5.47 MPa, with basalt filler – 5.2 MPa, and with leather powder (dust) – 4.25 MPa. The compressive strength of the composite with the addition of carbon filler (13.2%) was 4.2 MPa. The introduction of up to 14.2% of mineral fillers into the composition of the composite increases its heat resistance: when adding basalt filler – up to 106 °C, and wollastonite – up to 114 °C. Conclusion. The fractional composition of mineral fillers based on inorganic raw materials studied for their use in creating polymer composites. A hydro cavitation mill was made and a method for processing fillers from minerals and rocks was developed. New polymer composites were obtained with the addition of basalt, wollastonite, marble, and leather industry waste. Studies have been carried out on the physical and technical characteristics of these polymer composites depending on the content of fillers, such as basalt, wollastonite, marble and leather industry waste.
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Design and research of Nielsen arch bridge with fully composite structure system
Статья научная
China is the kingdom of arch bridges. Based on the principle of structural elastic potential energy standing value, the innovative application of the design theory of composite arch bridge bending and compression is presented, optimize the design of composite structural arch bridge arch axis, and propose the design and construction method of medium-bearing composite Nielsen arch bridge. The design of the medium-bearing composite Nielsen arch bridge is carried out, its structural strength, stiffness and stability are analyzed by finite element analysis. By simulating the parameters of arch axis, sagittal span ratio and arch section, the convergent composite arch axis with solid web foot section is adopted to improve the economic spanning capacity of the composite Nielsen arch bridge and expand the adaptation range of large span arch bridge in plain area or soft base area.
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Destruction of stable emulsions using nanodispersed fullerenes
Статья научная
Introduction. This article describes the results of the destruction processes studies of stable emulsion suspension sludge systems, conducted by the authors. Destruction processes are achieved by adding nanoparticles to demulsifying compositions. Currently, there is no universal composition demulsifier that effectively destroys emulsions formed in oil sludges. Research methods. To deal with this issues, the authors have conducted research on the creation of an effective demulsifier containing nanosized particles of fullerenes. The studies were carried out with dispersed oil-slurry emulsion-suspension systems, selected from open storage ponds of enterprises of JSC «Tatoilgaz» and JSC «TAIF-NK». For the destruction of the oil-containing system of the emulsion-suspension type, a composite mixture of complex action has been developed, which includes anionic wetting agents, nonionic surfactants, flotation reagents, detergents and alkaline buffer solutions that provide the required value of a constant indicator of the acid-base balance of the aqueous medium. Results and its discussion. A composite demulsifying mixture of complex action, which increases the effectiveness of the wetting washing action of surfactants, namely, the diphilic structure of the dispersed medium changes to hydrophilic, that is, the contacts of particles having a monophilic surface with the hydrocarbon phase of the emulsion medium are broken. When particles pass into the water volume from the phase separation boundary, the layer on the surface of the emulsified water is destroyed. The dehydration time of petroleum products is reduced by almost 2 times. Conclusion. During the research, the intensification and increase of the efficiency have been successfully reached.
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Determination of the amount of Ca(OH)2 bound by additive nano-SiO2 in cement matrices
Статья научная
Comparison of the content of Ca(OH)2 in hardened cement matrices, which contains the additive SiO2 nanoparticles and in matrice without additives was performed by the method of thermogravimetric analysis. Alite portland cement «SsangYong» and «Denki» were used. Hydrothermal sol of «Geosil» was introduced as an additive of nanoparticles of SiO2. The amount of introduced nano-SiO2 was from 1.15 to 1.74 wt.% in respect to cement consumption. Water-cement ratio was provided at the level of W/C = 0.39–0.26. The compensating amount of polycarboxylate SVC-5Neu was 0.2–0.77 wt. %. The Ca(OH)2 content was calculated from the mass loss of the cement matrice sample in the temperature range 460–510оC. It was determined that the sol «Geosil» additive reacts quickly with Ca(OH)2 (CH) in cement matrice, significantly (up to 40%) reducing its content. By the period of 24 h sol «Geosil» binds 750 [mg CaO /g SiO2] and continues to bind CH up to 100–700 days, to the value δCaO = 1300 [mg CaO /g SiO2]. The pozzolan binding reaction Ca(OH)2 with the formation of calcium hydrosilicates may be one of the mechanisms for increasing the strength of concrete when introducing SiO2 nanoparticles.
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Determination of the effective parameters of a triangular corrugated web for crane runway beams
Статья научная
Introduction. The aim of this study is to investigate the performance of crane runway beams with triangular corrugated webs. These beams are increasingly popular in industrial construction because of to their enhanced shear resistance and structural efficiency. Flat webs have several disadvantages, including high stress levels and excessive material consumption. Optimizing the geometry of corrugations makes it possible to improve strength and reduce the overall construction cost. Methods and Materials. The study is based on numerical modeling using the finite element method (FEM) in LIRA-CAD 2022 software and full-scale experimental testing. The performance of beams with both corrugated and flat webs was analyzed under wheel loads from cranes with lifting capacities of 10, 30, and 50 tons. Deformations and the distribution of normal and shear stresses were evaluated. Results and Discussion. The numerical model demonstrated high accuracy, with a maximum deviation of only 2.9% from experimental results. Crane runway beams with corrugated webs exhibited lower shear and normal stresses, reduced deflections, and more uniform force distribution. They also proved to be more economical due to lower material consumption and reduced labor intensity. Additionally, the corrugated beams showed enhanced economic performance, reducing material costs. Conclusion. Triangular corrugated web beams outperform traditional flat web beams in structural and economic terms. The findings support the use of optimized corrugation profiles to increase load-bearing capacity and reduce production costs. These results are relevant for optimizing crane beam design in industrial structures.
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Статья научная
Introduction. Currently, additive technologies are widely used across various fields. Their application in construction addresses several critical challenges. In the 3D printing process of small architectural forms, it is very important to choose the right composition of the materials from which they will be made. Materials and methods. We used for composition development: synthesized aluminosilicates as a nanomodifying additive, Portland cement without additives 52.5N as a binder, fine filler quartz sand from the Ukhtinsky and Chaadaevsky deposits, complex additive Sika Antifreeze N9, and superplasticizers Axton and C-3. The water retention capacity of formulations using a nanomodifying additive was determined by the amount of water in the test composition before and after the tests. The kinetics of water absorption of the compositions was determined in accordance with the methodology presented in GOST 5802. Porosity was determined by the content of free and chemically bound water in the cement stone. The change in the normal density and setting time was determined using the Vic device. The intergranular voidness of the sand was calculated from the values of the true and bulk densities of the fine aggregate. The true density was determined using the Le Chatelier device. The bulk density of materials was determined using the methodology established by GOST 9758. Results and discussion. It was revealed that the presence of a nanomodifying additive in the composition, with a dispersion of Sud = 0.69 m2/g and Sud = 1.03 m2/g, increases the strength of the compositions compared with the control ones (without additives) from 7% to 17.8%, respectively. That is, there is an inverse relationship between the dispersion of the introduced additive and the change in the strength of the samples. The high dispersion value of the introduced additive ensures optimal conditions for the hardening of compounds, which is confirmed by studies on the water absorption of compounds. During the research, the influence of the amount of the studied additive on the setting time of cement, changes in the normal density of cement dough and porosity of cement systems were evaluated. In order to reduce cement consumption and increase the mobility of the mixture composition, a fine filler is introduced – sand with a mixed grain composition. In the process of selecting the composition of the concrete mix for 3D printing of small architectural forms, their technological properties were taken into account. Four compositions of a concrete mix for 3D printing with different amounts of nanostructuring additive, sand, and cement were studied. Conclusion. Compositions with optimal characteristics have been identified for further research in the field of selection and development of concrete mixtures for 3D printing of small architectural forms.
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Development of a new PVC composition with reduced combustibility
Статья научная
Polyvinyl chloride (PVC) is one of the mostly plasticized polymers. The plasticizers used in this case are esters of aromatic or aliphatic acids with linear or branched aliphatic alcohols with a moderate chain length. Among them, phthalates (orthophthalic acid esters with fatty alcohols) have the widest range of applications among aromatic acid esters. They are characterized by excellent compatibility not only with PVC, but also with a number of other polymers, possess good physical and mechanical properties, but are toxic compounds. Therefore, their use is gradually being replaced by low-toxic and non-toxic plasticizers. Adipic acid esters which are widely used are environmentally safe. However, their use in plastic compounds for cable products requires the introduction of special additives – flame retardants. The results of the development of a low combustible PVC formulation are described herein. The dibutoxyethyl adipate developed by us was used as a plasticizer, and industrial di-(2-ethylhexyl) phenyl phosphate – as a flame retardant. First of all, we obtained an ester of adipic acid and ethoxylated butanol with a degree of ethoxylation of 5. Conditions of its production with maximum yield are selected. The physical and chemical properties of the synthesized compound were studied. Formulations of PVC compositions based on the obtained adipate with various amounts of di-(2-ethylhexyl) phenyl phosphate were compiled. Flammability tests of PVC compounds are presented. The combustible characteristics of the cable plastic samples using the developed plasticizers comply with state standard 5960-72 with changes 3-9. The best results were obtained by using phosphorus-containing additive in an amount of 3 wt%. It is shown that small amounts of di-(2-ethylhexyl) phenyl phosphate provide fire-fighting properties.
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Статья научная
Introduction. In the modern socio-economic and geopolitical development of Russia, the development of industry comes to the fore. Among the many industries, ammonia stations play the most important role. The main regularities of the process of pumping and preparing water. The process consists of six stages, this article discusses the automation of stages 1 and 2: for water treatment and pumping it out with pumps H1 and H2 from the tank P2. Products in the form of purified water are the most important criteria for subsequent production at an ammonia plant, therefore, increased requirements are imposed on the quality of finished products, including the quality of purification of the water used with the help of nanofilters. The required quality cannot be achieved without control the process in an automated mode. Development of a neural network. To control the converters frequency values during the preparation and pumping of water, an artificial neural network must be used. Its development was carried out in the Matlab environment in the Neural Network Toolbox package, input and output data were defined for this, data processing and preparation were performed, as well as the choice of the type and architecture of the neural network. The architecture of the Layer Recurrent neural network, the process of its construction and training in Matlab is described. Testing of neural networks. During testing of the Layer Recurrent network for the degree of their training, the smallest error was obtained for 30 neurons in the hidden layer. The proximity to the set values indicates the applicability of the network for controlling the parameters of frequency converters. Development of the neural network controller model in the Simulink package. The simulation of the control system in the Simulink package using a neural network controller with the Layer Recurrent architecture is performed. Checking the frequencies of the frequency converters H1 and H2 in Simulink for the level parameters in the tanks and in the tank LT1_вх, LT2_вх, LT3_вх showed that the object model works correctly, thus, the simulation of the neural network showed that the training was successful. Conclusion. As a result of the conducted research, an artificial neural network was developed to control the process of preparing and pumping water in the Matlab environment and a simulation of a neural network in the Simulink package.
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Development of armored products made from multilayer composite plates
Статья научная
Introduction. Modern requirements for personal and local armor protection dictate the creation of lightweight, durable, and efficient materials that can withstand a variety of threats, including shrapnel and low-velocity bullets. Conventional metal armor panels, while reliable, have a significant weight that limits their use. At the same time, ceramic materials, although they provide a high level of protection, are prone to the formation of secondary fragments upon impact. In this regard, composite materials such as aramid fibers and ultra-high-molecular-weight polyethylene (UHMWPE), which combine low weight with high strength and resistance to dynamic loads, are of particular interest. The article discusses the development of multilayer plates made from composite materials for personal and light armor protection. Methods and materials. Multilayer structures, including UHMWPE and aramid fabrics, were used to create armor plates. These structures were impregnated with epoxy resin and bioadditives such as collagen. The paper proposes a technology for the production of multilayer plates using aramid fabric and bioadditives. The technological process consisted of several steps: 1) a comprehensive study of the selected polymer materials with experimental determination of rigidity and strength characteristics; 2) cutting the fabric using a laser machine; 3) manufacturing an armor plate depending on the material and the loads subjected to it. Composite plates made from UHMWPE were created through hot molding using a press mold, and they consist of varying numbers of material layers. Multilayer elements (up to 30 layers) were made from aramid fabric with epoxy resin with bioadditives, which impart new elastoplastic properties to the material. Results. The ANSYS software package was used to calculate the strength of a multilayer composite plate under shock loading; field testing of the obtained plates as armor protection were also conducted, demonstrating good agreement with the calculations. Discussion. The obtained combined armor plates are highly effective in absorbing kinetic energy and preventing fragment penetration. Adding bioadditives to the epoxy matrix increased the interlayer defect zone, which contributed to the dissipation of impact energy. According to the authors, when adding bioadditives, the material acquires high fracture toughness. Conclusion (Findings). The developed armor plates offer a combination of low weight, no ricochets, and minimal deformation behind the barrier. This makes them promising for use in personal and local protective equipment. The use of bioadditives has improved the mechanical properties of the composite materials, and the test results confirm that the products comply with the Br3 protection grade, with a weight reduction of 25–30% compared to the analogues. The resulting products (low weight, absence of ricochet and traumatic consequences after impact) make them suitable for use as protection against shrapnel and pistol bullets.
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Development of environmentally friendly PVC compositions
Статья научная
Introduction. Polyvinyl chloride (PVC) is one of the most important polymers in the economy. Due to its versatility, this material is now found in a wide variety of products used in everyday life. A wide range of physical and mechanical properties is given to it by the use of additives, the main of which are plasticizers. The most common in terms of consumption are orthophthalic acid esters, in particular, dibutyl phthalate (DBP), dioctyl phthalate (DOP), diisononyl phthalate (DINP), diisodecyl phthalate (DIDP). Phthalates are well combined with polymers, give them high physical and mechanical properties, therefore plastic compounds based on them are widely used in the construction sector, engineering, as well as in agriculture and in everyday life. Numerous studies of products made from plasticized PVC, conducted in different countries, have established the adverse effects of DOP on human health, which led to the limitation of its areas of application. Legislative bans and growing consumer pressure are forcing PVC compound manufacturers to look for an environmentally friendly replacement for DOP. Methods and materials. In this research work, the possibility of creating more environmentally friendly PVC compounds using a mixture of plasticizers: industrial dioctyl phthalate and diisononyl phthalate and dibutoxyethyl phthalate (DBOEP) developed by us was studied. The choice of the plasticizers is based on the fact that DINP and DBOEP, in contrast to dioctyl phthalate, belong to the 3rd hazard class. Results and discussion. In the course of the correlation-regression analysis, a close functional relationship was obtained between the additives used and the characteristics of PVC, which was confirmed by the calculated coefficient of determination. Using the method of nonlinear programming applied to the constructed third-order polynomial dependencies, it was found that in the basic PVC composition formulation it is promising to replace up to 25 wt.h. DOP on DINP plasticizer. The joint use of industrial plasticizers DOP and DINP, as well as the developed DBOEP in the formulation of PVC compositions, indicates an increase in plasticity and manufacturability. This can probably be explained by the synergistic effect of the studied plasticizers. The dependence of the properties and content of plasticizers DBOEP and DINP in the form of a second-order surface was studied on the basis of the obtained experimental data, the level lines of the constructed function of two variables were studied, as a result of which it was found that the greatest effect is achieved at a dosage of: DOP – 25 wt.h., DINP – 5 wt.h. and DBOEF – 20 wt.h. Conclusion. The obtained research results show that the proposed formulation of the PVC composition makes it possible to reduce the toxicity of the plasticizers used by 50 % and improve the physical, mechanical and technological characteristics of the compounds.
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Development of heavy metal-based nanostructured complex technology for use in building mortar
Статья научная
Introduction. Heavy metals (copper, zinc, nickel, lead, chromium, cobalt, cadmium) get into constructional materials with natural and man-made raw materials. The chemical and mineralogical composition of large-tonnage wastes from the petrochemical industry is perfect for constructional materials production. Heavy metals in constructional compositions provide high strength and frost resistance. Currently, nanostructured metal-containing complexes are used in the production of mortars. Therefore, it is necessary to ensure the reliable binding of heavy metals into structurally stable compounds to avoid their emission and secondary environmental pollution. The steadily growing volumes of sludge reservoirs with high concentrations of heavy metals such as chromium (Cr +6), copper (+2), lead (+2), iron (+2), and Fe (+3) cause particular interest to researchers. Qualified extraction of the listed metals and binding them as nanocomponents in the composition of the complexing agent will ensure the creation of a nanostructural composition in the recipe for the preparation of mortar for various purposes. Methods and materials. Sorption methods are the main way to isolate heavy metals. The paper proposes a method for the production of alkyleneaminopolycarboxylic acids and studies its ability to form nanometallic complex compounds for the extraction of heavy metals. Results and discussions. In order to bind metal nanoparticles in oil sludge, the efficiency of the produced compounds, carboxymethyl derivatives of hexamine, was investigated. Optimum synthesis conditions were selected and the structure of the obtained complexing agents was proved by infrared and ultraviolet radiation methods as well as by the method of nuclear magnetic resonance. Conclusion. The resulting nanostructured additions have binding properties that provide high adhesion of the heavy metal to the organic substrate and mortar components, which makes it possible to provide a strong composition that maintains operational properties that meet technical requirements.
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Статья научная
Introduction. At present, the use of polymer coatings in the protection of metallic materials and structures is becoming popular in the construction industry. It is especially important to obtain nanostructured polymer insulating materials with high anticorrosive properties in order to ensure the service life of the equipment of the fuel and energy complex. Technological equipment during the extraction, transportation, processing of petrochemical raw materials is subject to regular exposure to aggressive environments. Damage to production equipment causes annual environmental damage and human health and material burden on the enterprise. The introduction of heteroatoms into the structure of the polymer molecule helps to improve the physico-chemical characteristics of polymer coatings, in particular, to increase the protective properties, since natural and synthetic polymer compounds represent a large cluster of supramolecular structures located in a certain sequence. Methods and materials. A technology has been developed for obtaining new polymeric nanostructured alkenylsuccinimides with anticorrosive properties, which can be used as part of lubricating coatings in various industries, including construction. Alkenylsuccinimides were tested according to TS 38101147-77 for succinimide additives and showed compliance with their standards TS 38101247-77. Results and discussions. In the course of the research a resource-saving non-waste technology of obtaining a nanostructured polymer additive with polyamines as a nanostructuring base to provide an anticorrosive effect has been developed. Conclusion. The obtained compounds based on triethylenetetramine, tetraethylenepentamine, alkenylsuccinic anhydride can be used as effective polymeric anticorrosion additives in the processing of metal materials and structures in the construction industry.
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Development of the actual state principle for a physical system
Статья научная
Introduction. The article briefly discusses the state of scientific research in the field of mathematical modeling of physical systems with distributed parameters. Mathematical modeling in elasticity theory. The initial boundary value problem of linear elasticity theory is formulated. It is shown that using measured and unmeasured variables, it is possible to construct a positive definite energy relationship, which allows not only to use the variational technique to find an approximate solution, but also to design objective estimates of its quality. Two-dimensional problem of elasticity theory (static case). Using the example of solving a two-dimensional static problem of linear elasticity, the advantages of the proposed approach are discussed in detail. Mathematical modeling in fluid theory. The variational principle in fluid theory is formulated. Optimal pressure control. Using the example of solving the problem of the motion control for ideal and viscous fluids in pipeline systems, the issues of finding an approximate solution and estimating its accuracy are discussed. Energy principle in the heat transfer problem. The variational principle in the linear heat transfer problem is formulated. Two-dimensional heat transfer problem. The features of constructing a solution to a control problem in a two-dimensional heat transfer theory are discussed in detail. Generalizing principle. A generalizing principle of the actual state of a physical system is formulated, which can be effectively applied for a detailed description and analysis of physical processes.
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Digital twin of a building as the basis for the application of nanotechnologies in construction
Статья научная
Introduction. The purpose of the conducted research is to analyze the possibilities provided by the “digital city” system and the prospects for the application of nanotechnologies. The objective of the research is to determine the possibility of digitalization in city management and the process of making more substantiated decisions regarding real estate operation. The practical application opportunities of the research results are due to the feasibility of implementing the author's approach to analyzing the operation of urban systems in general and “smart home” in particular. Methods and materials. The article explores the concept of “digital twin of a building,” its functions, components, features of construction and operation using digital twin technologies. The concept of digitalization is characterized, as well as mechanisms for introducing innovations into urban life. It is demonstrated that the “digital city” incorporates various innovative technologies: Internet of Things, artificial intelligence, data analytics, cloud computing, etc. The technologies utilized by the “digital city" not only collect data on urban life but also employ obtained data for managing electricity supply, waste collection, ensuring people's safety, and as elucidated in the article, transportation systems. Discussion. Digitization in urban management helps to create a more convenient and sustainable urban environment, a goal pursued by the governments of many countries. The implementation of sensors, detectors, and the analysis of data obtained from them provides an opportunity to improve the quality of life for urban residents and increase the efficiency of resource utilization. As a pleasant “bonus,” all of this allows making the living environment of citizens more environmentally friendly, addressing an issue that has been a “headache” for many governments – the issue of greening human existence in the city. After all, reducing the number of traffic jams automatically reduces the amount of carbon dioxide emissions, and turning on city lighting based on sensor signals saves electricity due to a reduction of consumed kilowatts since the bulbs are not unnecessarily lit. To address these issues, the use of nanotechnologies is proposed, which will enable ordinary building materials to acquire new unique properties. The emergence of nanotechnologies and their application can solve the problem of energy conservation in the construction industry. Moreover, nanotechnologies not only allow for the production of new products with unique properties but also enhance the efficiency of materials used in construction. In this regard, the key question for determining the application of nanotechnologies is the exploration of their integration into the digitization system of city management, which already incorporates a multitude of innovations and new technologies that help optimize the work of municipal services and improve the quality of life for urban residents. Conclusions. The author concludes that the provision of services by many urban services is based on 3D design technologies, as well as data collected within the framework of the “digital city” system.
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Статья научная
Introduction. The porous composite and nanocomposite materials discussed in this publication are metallized carbon-graphite materials, in particular carbon fiber materials (CFMs). At metallization of CFMs one of the actual problems is the task of applying uniform metal coating on the surface of CFMs fibers over the entire volume of the processed material. One of the most effective ways to coat CFMs with metals and their alloys is the galvanic method. This method allows, among other things, to optimize the process by optimizing both the design of the electrolyzer with flow-through three-dimensional electrodes (FTE) and the choice of electrodeposition modes, such as galvanic, concentration, and hydrodynamic. Materials and methods. Methods of mathematical modeling of porous medium metallization processes and previously published experimental data were used to solve problems on calculation of operating modes and elements of the electrolyzer design, in particular, the specific reaction surface of the UWM distributed over the thickness of the electrolyzer. Results and discussion. The development of mathematical models of the processes of electroplating metallization of CFMs is carried out. Boundary value problems of mathematical physics are formulated and calculation methods are proposed. Problems of optimization of distribution of specific reaction surface of CFMs by thickness of FTE on the basis of electrochemical theory of processes in porous medium are set, ways of their solution are presented. Specific technological problems are solved. The comparison of the most effective values of the distribution of specific reaction surface of CFMs over the thickness of FTE obtained as a result of modeling with the experimental data is given. The workability of models and methods for studying the process of copper electrodeposition from sulfuric acid electrolyte is shown. Conclusion. Calculation of regularities of electrochemical processes of metal extraction in FTE on the basis of the developed mathematical models allows to predict the results of electrolysis, determine the optimal modes of operation and elements of FTE design. The use of FTE for metallization of CFMs with properly distributed reaction surface contributes to obtaining composite materials with specified properties.
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Статья научная
Introduction. Currently, carbonate reservoirs play an increasingly significant role in the global hydrocarbon balance. Most of the deposits discovered in recent years are fractured carbonate reservoirs. The potential for effective development of carbonate reservoirs lies in the development and application of new high-tech methods and advanced well drilling technologies. The article highlights the challenges of developing productive deposits in the Paleozoic basement of Tomsk region deposits represented by fractured carbonate reservoirs. The article considers the mining and geological conditions of carbonate reservoirs in the Paleozoic basement and the challenges that arise when using traditional drilling technologies. The article presents the results of an analytical review on the application of advanced technologies for drilling wells with horizontal completion. Some aspects of the application of nano drilling fluids for conditions of low-permeability carbonate reservoirs are highlighted. The content of the article is based on the author's research and analysis of publicly available literature. Methods and materials. The work is based on the generalization, systematization and analysis of factual material, scientific publications, and results of analytical studies. Results. Based on the generalization and analysis of geological and field data, the authors established that in the conditions of the identified group of fields, when developing fractured carbonate reservoirs, the productivity of a well depends on the number of natural cracks opened during drilling that penetrate carbonate rocks. Fault tectonics had a major impact on the development of highly fractured zones of carbonate reservoirs, which are the main reason for frequent absorption of drilling fluid when drilling wells with a horizontal end. Clustering of the well stock of the development object in carbonate reservoirs allowed to identify 3 groups of wells, opening up deposits with different filtration-capacity characteristics. It was established that the nature of the distribution of porosity and permeability depends on the development of reservoir fracturing associated with the position of tectonic faults. Analytical studies in the perimeter of Russian oil and gas companies have shown that the efficiency of well drilling technologies in fractured carbonate reservoirs is achieved through an integrated approach: detailing the geological structure of the target object, adapted drilling technology with the ability to regulate differential pressure in the well-formation system, as well as selecting optimal drilling fluids.
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Dry building mixes with a silica-based modifying additive
Статья научная
Introduction. The use of dry building mixes has broad potential for use in construction due to their stability of properties, the ability to provide a specific set of quality characteristics to the material, and reduced production waste. When developing compositions of floor dry building mixes, it is necessary to ensure high mechanical properties, reduce shrinkage deformations, crack formation, and provide high adhesion to the concrete base. Expanding the range of dry building mixes, using local raw materials and modifying additives for various functional purposes for their production is an urgent task for the construction industry. Materials and methods. To ensure the rheological and technological properties of the dry building mixes, low water demand binders were produced based on Portland cement, volcanic slag, fly ash and dry superplasticizer on a polycarboxylate basis. To regulate the technological properties and increase mechanical properties of dry building mixes, a reinforcing additive in the form of basalt fiber and nanosilica was used. Results and discussion. The compositions of self-leveling dry building mixes were optimized according to the criteria for achieving the highest mechanical properties. The water-holding capacity of the mixes, compressive and flexural strength, water absorption, crack width, abrasion, and adhesion strength to the concrete base were determined. The microstructure of the mortar was studied using scanning electron microscopy. An assessment was made of the influence of modifying additives on changes in the properties of flooring dry building mixes. Conclusion. The resulting compositions of dry building mixes comply with the requirements of state standard for self-leveling flooring building mixes. With the use of a complex of mineral, plasticizing, micro-reinforcing, nano-sized additives, high performance indicators of flooring building mixes have been achieved.
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Статья научная
Introduction. The effect of adhesion additive and nature of filler on fatigue life and interfacial interaction in mastic is analyzed in this paper. Materials and methods of research. Frequency sweep from 0.1 to 100 rad/s at strain 0.05% at temperatures from 30 to –10°С with a step 10°С and cyclic tests (LAS test) at temperatures from 16 to 1°С with a step 3°С for bitumen grade BND 100/130 and mastics based on it, containing fillers of different nature, were performed on the dynamic shear rheometer. Mastics were prepared by mixing bitumen (3 min; 160°С and 600 rpm) and filler (filler volume fraction – 0.275). Adhesion additive in an amount of 0.7%, was introduced into bitumen before the filler to investigate the effect of AD on the properties of bitumen and AB. The damage characteristic curve under cyclic loads was calculated using two models of VECD theory (Viscoelastic Continuum Damage Modeling System): dissipated strain energy and pseudo-strain energy. Results and Discussion. The influence of nature and properties of filler, adhesive additive, temperature and frequency of tests on the parameter of interfacial interaction K-B-G* and thickness of adsorbed layer has been investigated. The intensity of damage in the specimen under cyclic loads and the behavior of fatigue parameters as a function of test temperature at two variants of determining the parameter α have been analyzed. Conclusion. It is shown that an increase in the interfacial layer thickness in asphalt mastic leads to an increase in their resistance to damage accumulation (Damage Intensity) during fatigue testing (LAS), and lowers the rate of pseudo-deformation energy growth.
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