bluuebunny/crossref_metadata_2025 huggingface dataset:
A constitutive framework for the chemo-mechanical behaviour of unsaturated non-expansive clays
Authors: Gramegna Liliana , Abed Ayman A. , Sołowski Wojciech T. , Musso Guido , Vecchia Gabriele Della
Published: April 2023

Both osmotic and matric suction changes have a significant influence on the mechanical behaviour of clays. Despite the different types of interactions at the microstructural level, both suctions havea relevant effect on the fabric of non-expansive clays. Starting from experimental observations at the laboratory scale, it is possible to identify some common features characterizing the mechanical response of non-expansive clays to salinity and degree of saturation changes. This paper presents an elastoplasticframework to reproduce the behaviour of unsaturated clayey soils upon changes in the salt concentration of the pore fluid. In particular, it presents a strategy to include osmotic suction induced by pore fluid salinity in BBM-like models [1]. The model was implemented in the Thebes code and it was calibrated on experimental data performed on Boom clay [2] and remoulded loess [3].
A state dependent constitutive model for unsaturated soil-steel interfaces considering bonding effect
Authors: Liu Gengyun , Li Jingpei
Published: April 2023

The frictional behaviours between unsaturated soils and structure are controlled mainly by the complex phenomena that develop within a thin soil layer close to the contact area. The constitutive model for soil-structure interfaces (SSI) must be established to predict the performance of related soil-structuresystems accurately. Multi-stage suction-controlled ring shear (RS) tests with three different upper annular platens were carried out on an equal number of statically compacted samples of Shanghai clay under controlled suction states for a given net normal stress. A state dependent constitutive model for unsaturated soil-structure interfaces based on critical state concept considering bonding effect was proposed. In all stress conditions, the tested and predicted results for smooth interface and rough interface are well matched.
Constitutive modelling of instabilities and strengths of an unsaturated tailings
Authors: Wang Yanzhi , Vo Thanh , Russell Adrian
Published: April 2023

Instabilities mostly happen in fully saturated and loose non-cohesive geomaterials like sands or silts or tailings, but it is also possible in unsaturated geomaterials. When unsaturated they can experience a reduction in effective stress and strain soften during water (and air) undrained loading, attaining a very low residual strength. This study focuses on modelling the conditions required to cause instability in unsaturated silty tailings, giving particular consideration to the presence of air and the way it alters the ability for volume change when it remains trapped inside the tailings. A gold tailings is used to calibrate the UNSW boundingsurface plasticity model. The effect of air, including the volumetric change caused by air compression, the alteration of air pressure, the contribution of suction to the effective stress, and suction hardening, are explored. Collapse lines (sometimes referred to as instability lines or flow liquefaction lines which represent boundaries between stable and potentially unstable stress states) in the 𝑞𝑞 − 𝑝𝑝′ plane are explored. The undrained shear strength ratios and slopes of the collapse lines are compared to those of other tailings andsands when unsaturated.
Reproduction and long-term monitoring of drying of mudbricks and small mudbrick walls for the preservation of the ancient mudbrick wall of Eleusis
Authors: Bardanis Michail , Marinis Theodoros , Toumbakari Eleni-Eva , Dounias Georgios
Published: April 2023

The mudbrick wall remains preserved to date in the site of Eleusis are some of the largest preserved in Greece. Following an extensive investigation of the properties of existing mudbricks, material of similar properties from the archaeological site of Eleusis was used to reproduce mudbricks of similardensity with the ancient ones after drying with various concentrations of dry grass also from the archaeological site. Actual mudbricks were reproduced and brought to a final equilibrium condition under climatic conditions practically similar to those in Eleusis. Others were used to trim samples and measuremechanical properties to compare with original mudbricks, others were instrumented with suction and volumetric water content sensors in order to monitor mudbrick drying under climatic conditions and others in order to build small mudbrick walls with mortar from the same soil used to make the mudbricks. These small mudbrick walls included the mudbricks with internally installed suction and volumetric water content sensors and were also constructed with similar sensors in the mortar. This allowed monitoring of drying of the mortar until each whole mudbrick wall came to equilibrium and was then subjected to uniaxial compression under load control. Monitoring of mudbricks and mudbrick walls indicated that the higher the dry grass concentration, the higher the drying rate of the mudbricks; the lower the dry grass concentration the higher the probability of mudbrick cracking during drying; minimum required time for mudbrick and mudbrick wall drying for the particular soil used in the ancient mudbricks is not less than 5 weeks. Finally, uniaxial compression under load control on both samples trimmed from dried mudbricks and mudbrick walls indicated that uniaxial compression strength decreases with increasing dry grass concentration and mudbrick wall strength should be expected in the order of 70-80% that of the cubic samples trimmed from dried mudbricks and subjected to load rate control compression.
Unlocking the water retention behaviour of turf construction materials
Authors: Yi Xin Lin Benedicta , Beckett Christopher , Romankiewicz Tanja , Snyder J Riley , Russell Ben
Published: April 2023

Turf is not a material frequently associated with construction. However, as a cheap, easily available, and versatile material it was used in antiquity (and has been used in various contexts since) to form unit-based and mass walls, embankments, and ramparts. Some of the best-preserved evidence for historical turf use comes from the Roman period, when it was a mainstay of military construction, being widely used in forts (e.g. along the Rhine and in Britain) and large-scale linear earthworks, most notably thewalls of Hadrian (northern England) and Antoninus Pius (central Scotland). To our knowledge, turf has never been examined as a construction material; its interest has, until now, been restricted to the soil and agricultural sciences and sports engineering. This paper presents the first exploration of turf water retention properties, assessed to understand whether turf behaviour can be collated with that of more traditionalearthen materials, for example cob or rammed earth. Tensiometer and psychrometer methods were used to estimate the water retention curves of turf, representative of that used for construction, harvested from two sites near Crieff, Scotland. The obtained data were analysed in terms of unimodal type functions to understand qualities of the full range of the soil water retention curve for Scottish turf. This work supports a larger project examining how engineering materials principles can explain ancient construction practices. In so doing, we will be well positioned to reintroduce this low-carbon material to the modern construction market.
Modelling of water droplet dynamics on hydrophobic soils: a review
Authors: Zhang Shuaihao , Hu Xiangyu , Lourenço Sérgio D. N.
Published: April 2023

The hydrophobicity of soils (or soil water repellency) can be naturally promoted by wildfires or synthetically induced by hydrophobic compounds (polydimethylsiloxane, tong oil, etc.). Soil phenomena can be related to hydrophobicity, such as soil erosion (splash erosion and rill erosion) and post-wildfire debris flows. The hydrophobicity of soils is characterized by the contact angle, and the interactions between water droplet and solid particles including spreading, oscillation, and infiltration. Early studies on soil water repellency mainly focus on the experimental aspects, while with the development of advanced numerical tools, numerical methods have been widely applied to study the hydraulic properties of hydrophobic granular materials in recent years. This paper comprehensively investigates the different numerical methods for modelling the interaction between water droplets and hydrophobic soils, i.e., smoothed particle hydrodynamics (SPH), lattice Boltzmann method (LBM), material point method (MPM), and volume of fluid (VOF). The features of different method are summarized, and the future work are discussed.
Milos, the minerals island and its important asset: Bentonite
Authors: Stamatakis Michael
Published: April 2023

The island of Milos is an active mining site since the Antiquity. Exploitation began with the extraction of obsidian lumps and volcanic lavas and tuffs of specific type, that were used as millstones, sulphur and alum (alunite). Currently, the mining activity is focused on perlite and bentonite, even though some years ago, kaolin, silica, pozzolans and barite were also exploited. Milos bentonite is rather a specialty and not a commodity, as it has multifunctional properties, and therefore used in a wide range of industrial applications, such as foundry sand, drilling muds, lubricant oil, civil engineering structures (waterproofing and sealing, diaphragm wall construction, grouting, concrete workability additive, etc.), cat litter, iron ore pelletizing - Fe metallurgy in blast furnaces and also as “improver” for poor quality bentonites. The peculiar behaviour of Milos bentonites can be attributed to the combination of various geological and hydrogeological factors that occurred at the time of its formation from a glassy tuff precursor. Despite the continuous flourishing of tourism at the island, the mining activity does not face any threats to its existence, as both parties follow the specified regulations and environmental restrictions necessary to allow dual economic growth.
Physically-based reduction function to model unsaturated flow associated with plant transpiration
Authors: Roberts-Self Eve , Tarantino Alessandro
Published: April 2023

Vegetation plays an important ‘hydrological’ role in stabilising geostructures. Soil water is extracted by the roots due to transpiration, this increases soil suction and, hence, soil shear strength. Transpiration occurs in two different regimes, energy-limited and the water-limited regimes respectively. These two regimes are reflected in the two branches of the transpiration reduction function used to model the hydraulic boundary conditions for vegetated ground. The water-limited branch accounts for the reduced transmissivity of the soil-root system when the degree of saturation and, hence, the hydraulic conductivity declines. The water-limited branch of existing reduction functions (e.g., Feddes function) is defined in purely phenomenological fashion with parameters that have no clear link with the complex interaction between soil hydraulic properties and root architecture. A paradigm shift can be achieved through physically-based reduction functions. These require analytical closed-form solutions of radial water flow at the soil-root interface that, in turn require introducing simplifying assumptions, i.e., steady-state flow and a simplified hydraulic conductivity function. This paper explores the implications of these assumptions by i) benchmarking the water-limited branch of the reduction function derived analytically against the one derived numerically for more realistic hydraulic behaviour and ii) assessing the steady-state assumption.
When nature meets technology: AI-informed discovery of soil-water-root physical interaction
Authors: Kwan Leung Anthony , Liu Jianbin , Jiang Zhenliang
Published: April 2023

Nature-based solution using vegetation has been considered as a sustainable and environmentally friendly approach to improve slope performance through root reinforcement and variations of soil matric suction upon transpiration. During plant growth, roots explore soil pore space. How fundamentally the pore structure might evolve with time following root growth dynamics and how this dynamic soil-root interaction may modify the hydraulic properties of unsaturated soils remain unclear. This paper reports the use of advanced technologies including artificial intelligence (AI) to aid the discovery of soil-root-water physical interaction and the characterisation of the hydraulic properties of rooted soils. A newly developed miniature unsaturated triaxial apparatus that enables rooted soil samples to subject to simultaneous in-situ loading and X-ray imaging is introduced. An AI-informed image processing technique is illustrated, aiming to enhance the reliability of phase segmentation of X-ray computer tomography (CT) images of four-phase unsaturated rooted soils for quantifying 3-D pore structure and root phenotype. New discoveries of how roots interact with the pore space, including the dynamic changes in the distribution, orientation and connectivity of soil pore sizes, and how this pore-level information can be used to explain the hydraulic properties are discussed.
Efficacy of Pond Ash as a Cover Material in Single and Dual Capillary Barriers
Authors: Srikanth C.S.S.U. , Ramaiah B.J. , Murali Krishna A. , Vanapalli Sai K.
Published: April 2023

In this paper, numerical study results that highlight the capability of using pond ash as a cover material in covers with capillary barrier effects are succinctly summarized. A model was exclusively developed and calibrated using commercial software SEEP/W for this study. After calibration, the efficiency of pond ash as a coarse-grained layer (CGL), fine-grained layer (FGL), unsaturated drainage layer (UDL), and seepage control layer (SCL) was investigated using various combinations. The CCBE made of pond ash obtained from the output and input points of an ash pond as alternate fine- and coarse-grained layers were observed to perform well. The performance of pond ash as UDL and SCL was also observed to be good. The approach presented in this study is valuable in assessing likely slope failures of coal ash storage facilities that may be triggered by rainfall events. The study aids in significantly reducing rainfall infiltration, improving the overall stability of the slopes, and promoting sustainability by utilising the concept of “waste covering waste”. The approaches used in this study can be extended in the rational design of slopes to address the future challenges anticipated with unprecedent rainfall events and its negative impacts associated with climate change effects.
Spatiotemporal deep learning approach for estimating water content profiles in soil layers
Authors: Fazel Mojtahedi Farid , Ghaffari Mohammad Amin , Rahmati Saeed , Nazari Ali , Sadeghi Hamed , Vanapalli Sai K.
Published: April 2023

Land subsidence associated with using natural groundwater resources for serving the growing population needs has been receiving extensive research attention in the literature over the past few decades. The water content fluctuation in the of subsurface soil layers significantly impacts the land subsidence. The key objective of this study is to predict changes in water content profiles in soil layers over a long period of time using a deep learning-based approach. A convolution neural network algorithm that is commonly used in Artificial Intelligence (AI) applications is modified in the present study for processing in-situ measurement water content profiles. The approach used in the proposed AI method has a distinct advantage for generating dynamic predictions based on the extracted spatiotemporal characteristics of the data. In addition, three different algorithms are compared with respect to time series prediction, including long-short-term memory (LSTM), multiple-layer perceptron (MLP) networks and autoregressive integrated moving average (ARIMA).
The importance of desiccation cracks in water migration inside expansive ground
Authors: Loukidis Dimitrios , Tzampoglou Ploutarchos , Stylianou Thrasivoulos , Pogiatzis Loizos , Lazarou Georgia
Published: April 2023

Highly plastic clays are generally regarded as very impermeable materials. However, it is well known that desiccation cracks, as well as inherent fissuring, increase the in-situ apparent permeability inside the active zone. The paper presents long-term measurements of matric suction and moisture sensors installed under a mat foundation, on the shaft of bored piles, and at the free field in expansive marls in area of Nicosia, Cyprus. The data reveal the ease with which rainwater percolates in the ground due to the presence of shrinkage cracks, especially adjacent to foundation elements. Several episodes of full saturation conditions are recorded under the mat close to its perimeter during the course of a hydrological year after significant rainfall events, even during the dry season. Moreover, rapid migration of rainwater along the gap forming between the soil and pile shaft during the dry season can lead to brief full saturation incidents down to at least 1.5m depth. Back-analysis of field wetting experiments using the finite element method indicates that the equivalent in-situ saturated hydraulic conductivity of highly expansive marl near the ground surface is 3 to 4 orders of magnitude larger than the one measured on intact marl samples in the laboratory.
Field monitoring of the water pressure and displacement of a partially saturated expansive marl under an unloading stress path due to deep excavation
Authors: Ouédraogo Missom , Boutonnier Luc , Emeriault Fabrice , Mahmutovic Dino
Published: April 2023

This paper presents, an in situ monitoring of the behaviour of a partially saturated soil, subjected to an unloading stress path resulting from excavations. The study case is a 30m deep excavation for the construction of a metro station, The aim of the study is to monitor the evolution of displacements and pore pressure during and after the different stages of excavation. The monitored soil is an expansive marl. The first results have been collected and analysed. Nevertheless the monitoring system should remain in place for a few years.
Soil parameters in terms of entropy coordinates
Authors: Imre Emőke , Firgi Tibor , Baille Wiebke , Datcheva Maria , Barreto Daniel , Feng Shuyin , Singh Vijay
Published: April 2023

In the ongoing research, an approximate, grading entropy based, advanced interpolation method is applied to establish empirical functions between the grading curves and the model parameters of sands. The space of the grain size distribution curves withNfractions is isomorphic to the space of the unit-sided simplex with dimensionN-1. The traditional interpolation over the simplex with dimensionN-1 is problematic since the number of the sub-simplexes (and the interpolation points) may increase exponentially withN. To overcome this difficulty, the function is approximately interpolated, which means that the interpolation is made on some 2-dimensional sections of the simplex and is extended to the whole simplex, using the grading entropy map. Two kinds of 2-dimensional sections can be used based on either fractal distributions or partly fractal partly on some maximal gap-graded distributions. In this paper the experiments were made on the artificial mixtures of natural sand grains earlier. Two kinds of functions were approximately interpolated for the minimum dry density using the measured data. One kind of function was determined for the parameters of an SWCC model directly from the level lines previously graphically interpolated from fractal distribution data.
Improvement of the system of transport-transfer hubs on the example of St. Petersburg agglomeration
Authors: Gorbunova M. , Novichikhin A.
Published: April 2023

The article proposes a conceptual framework with empirical foundations, prerequisites, theoretical foundations and implementation, and validity criteria. It also presents methods to improve transport and interchange hubs on the example of the St. Petersburg agglomeration, aimed at improving the efficiency of hubs operation, developing infrastructure and stations, improving the capacity of the transport network, achieving uniform loading system and traffic safety, increasing the attractiveness of rail transport for the population, increasing the index of passenger satisfaction. The analytical review of normative documents, theoretical provisions, programs and measures, carried out and planned for implementation for the development of St.-Petersburg railway junction has been made. The existing models of transport-transfer hubs in the St.-Petersburg agglomeration were investigated and the directions for their improvement were revealed by creating the concept. On the basis of the proposed synergistic-logistic concept, the provisions to ensure the improvement of transport-transfer hubs (on the example of the St. Petersburg agglomeration) have been developed.
Analysis of the investment attractiveness of the “green” bonds of JSC “Russian railways”
Authors: Satsuk Tatyana , Lobodina Renata
Published: April 2023

The present scientific article reveals a brief description of investment projects in the energy industry. The principles of green financing and the practice of its application in the Russian Federation are revealed. There have been identified the directions, the development of which should increase the attractiveness of socially and environmentally responsible investment of funds. There has been carried out the analysis of the investment program of the energy enterprise, which is part of the transport holding. Scientific research methods. There have been surveyed global approaches to estimation of investment projects, in particular, the investment program of the enterprise, which is part of JSC “Russian Railways”, has been investigated and estimated. Outcomes and conclusions. The indices of the assessment of “green finance” of various countries are considered, the criteria for the verification of projects and programs that support the social well-being of society and the policy of caring for the environment are investigated, the normative acts regulating ESG financing in the Russian Federation are characterized. The obtained outcomes of the research of this article could be applied in the sphere of estimation of investment programs of the energy and transport industries for compliance with ESG principles.
Building materials for railway sleepers intended for operation in the arctic zone
Authors: Poletaev Alexander , Chistyakov Eduard , Dzhashi Natela
Published: April 2023

The article shows a picture of climatic changes in the Arctic zone, presents the advantages of reinforced concrete sleepers, argues the necessity of using in the Arctic zone sleeper materials with high strength and frost resistance, high deformation and corrosion resistance, gives a brief historical overview of the contribution of St. Petersburg University of Railway Transport to the development of highly effective materials for the production of critical structural elements of the upper structure of the railway Data on the change in the strength and deformation characteristics of slagalkali concrete for reinforced concrete trusses after 10 years of operation are presented. The paper assesses the state of the reinforcement and the factors influencing the possible corrosion development: dynamics of alkali binding, composition of passivating films and the adjacent layer of concrete, microstructural analysis of the reinforcement.
Structure and distribution of function between the stages of the information and measurement system for diagnostics of traction substations and contact network installations
Authors: Yakubov Mirdjalil , Karimov Islom , Abdullaev D.
Published: April 2023

The article presents the results of the study of the multistage information-measuring system (IMS) of the diagnostic of traction power supply objects combined with the operational-dispatch control allowing to ensure reliability, attributing to unit value of the IMS. Taking into account the introduction of functional redundancy in the structure of duplicate channels of diagnostics of each stage. he upper level of the complex should maintain processing of information received more frequently from previous devices and issue of certain tasks to the operating personnel for the work of maintenance according to the actual condition of the diagnosed facility. Based on mathematical models of reliability of primary converters and information processing devices on probabilistic indicators. The functional block-circuits of the multi-stage IMS for obtaining and converting information on the example of power transformer diagnostics and contact network devices are disclosed. It has been shown that, given the vulnerability of communication channels, it is advisable to transmit information in large flows, for example, related to spectral analysis, to process at the lower stages of the IMS, and through communication channels to transmit their integral indicators.
Stress-strain magnetoactive propulsion system
Authors: Minaev Andrey , Korovkin Jury
Published: April 2023

It is possible to create deformations in magnetically active polymeric materials by applying magnetic fields to them. This work develops a symmetrical design scheme of the device, in which the drive and control are carried out by two actuators located on opposite sides. The symmetric scheme with control from two sides allows transporting objects (cargo) in mutually opposite directions (forward and backward). It is proposed to use a magnetically active gel together with a magnetically active elastomer as magnetically active materials. The resulting force effect in the device actuator is produced by interaction of magnetic fields of electromagnets with magnetic fields of permanent magnets. Expressions for obtaining alternating magnetic fields which create conditions for generating alternating magnetic forces in the actuator of the device are given. A prototype design with a controller control device in which signals are generated for an optimum current pulse generator with adjustable duty cycle and duration is presented.
Application of GIS technologies for engineering geodynamic zoning of mountain territories
Authors: Kuropatkina Tatyana , Lyubimova Tatyana
Published: April 2023

The lack in practise of applying special engineering-tectonic studies in the course of standard engineering surveys does not allow us to fully take into account the features of engineering-geological conditions of mountainous territories.In the work for the section of the Black Sea coast from Gelendzhik to Tuapse, which is part of the Afipsko-Defanovskaya orographic stage, a detailed study of discontinuous structures was carried out using cartographic constructions. The use of the GIS technology tool made it possible to carry out an overlay analysis of maps of morphometric indicators, as well as to draw up a diagram of tectonic blocks. The results showed good convergence with the data obtained earlier on a smaller scale. This provided the basis for zoning the territory according to the degree of favorability of engineering and tectonic conditions with the involvement of morphometric and tectonic features. The study of this territory was conducted for the first time and contributes to the clarification of its neotectonic structure, expanding the scope of application of structural and geomorphological methods based on GIS technologies in engineering and geological research.
Peculiarity and functionality of the digital educational ecosystem for transport and logistics
Authors: Drozdova Maria , Fursova Elena
Published: April 2023

The article presents the results and interpretation thereof of a study of the transport education transformation as a digital educational ecosystem in the context of the global digitalization processes, the strategy of the state, intellectual priorities for transport and logistics, the market demands. Certain potential innovative forms of modern education are suggested, namely the combined use of university educational resources and employer’s materials and technical resources. They are studied on the example of the first Russian transport engineering higher education institution, Emperor Alexander I St. Petersburg State Transport University (PGUPS), where their ongoing implementations are called ‘Innovative site for international educational programmes of proactive training of high-speed railway personnel’, ‘Network University’.
Solving logistic tasks by parallelizing algorithms of the theory of direct decompositions of torsion-free abelian groups
Authors: Blagoveshchenskaya E. , Gruzdev N. , Zuev D.
Published: April 2023

The paper considers the principles of parallelization at marshalling yards and determines their importance. There are presented the methods for direct decompositions of torsion-free Abelian groups of finite rank. There are applied the concepts of “conditionally linear graphs” depicting railway trains and their characteristics, including “quasi-length”, which characterizes the length of the corresponding “quasi-graph”. There has been formalized a graphical approach to the redistribution of railcars of incoming trains at a marshalling yard for the formation of outgoing trains. The corresponding algorithms have been developed.
Numerical simulation of slurry basin impeller operation for mixing slurry mixtures in the production of cement compositions
Authors: Benin A. , Vataev A. , Vatulin Y.
Published: April 2023

The issues of numerical modeling of hydrodynamic resistance of the impeller for mixing slurry mixtures in the production of cement compositions are considered. Mathematical models based on the finite element method to analyze the hydrodynamic processes occurring in the mixing of cement-containing mixtures are developed. The influence of rotor design on the value of torque power on the impeller shaft has been investigated. It is established that the most acceptable option is a vane design that creates a good turbulence of the fluid medium in almost the entire volume of the process equipment, contributing to high-quality hydration of cement composites. Optimized power of the drive by the criterion of hydraulic resistance and the number of revolutions of the impeller.
The role of Professor Betancourt in preservation of architectural heritage in historical cities of the world
Authors: Ulitsky V. , Shashkin A. , Awwad T. , Abu-Khasan Mahmud
Published: April 2023

One can address an issue which generates an argument of colleagues-civil engineers, architects and mechanical engineers working with machines. Bridge engineers can also enter the discussion stating that a world-renowned scholar Augustin Betancourt belongs to their “bridge” community. He had an experience of constructing bridges and floors with large spans. His structures and ideas in all these directions of engineering thought were broadly used and even now they are applied in the modern world practice. We can give a lot of examples, as A. Betancourt’s structures and ideas have been used by many engineers including the authors of this paper in their long-term practice of reconstruction of the unique buildings in Russia. There are dozens of buildings and structures only in St. Petersburg and its closest suburbs where A. Betancourt was an author, an advisor, an expert, whose indications were implemented in many projects of urban development. A. Betancourt was actively involved as a head of the Committee for Construction and Hydraulic Works in St. Petersburg. This committee also participated in expert evaluation of development of the largest Russian cities of that time.
Mesoporous silica nanocatalyst used in the preparation of the retention substance bentonite-sorbents sorption of isotherms research
Authors: Fayzullayev Normurot , Kurbonov Jamshed , Yusupova Nargiza , Akmalaev K.A. , Kurbanova Raxima , Kurbonov Jaxongir
Published: April 2023

In this study, the retention substance bentonite was used in the preparation of a mesoporous silica nanocatalyst. The analysis of sorbents from the sorption isotherm study and the results obtained were summarized. Also discussed are the chemical composition of bentonite from the Navbahor deposit, the types of sorbent isotherms obtained by the adsorption of various gases on sorbents, descriptions of sorbent isotherms in mesoporous sorbents, the phase composition of sorbent samples synthesized from textures, and the physic-chemical characteristics of the X-ray diffractometric catalyst, and the dependence of the characteristics of texturs of the characteristics of nanocomposite sorbents made from bentonite.
Energy analysis of wear sliding friction units
Authors: Ishmuratov H.K. , Mirzaev N.N. , Abdullaeva B. , Mamasalieva M.I.
Published: April 2023

This article deals with the calculation of friction and wear of working surfaces of sliding friction units on the basis of energy theory. Working surfaces have roughness, i.e., protrusions and depressions, which under the influence of load and as a result of slip undergo plastic deformation, as a result of which the roughness of contacting surfaces changes and differs from the initial one, which is called equilibrium roughness. Profilograms of surfaces with equilibrium roughness showed that their protrusions have approximately the same height and large rounding radii, which causes a large contact area of the mating friction surfaces. The intensity of wear of the friction pair depends largely on the normal load on the contact areas. If the contact stress does not exceed the yield strength of the tooth material, the wear of the friction surfaces occurs without seizure, if the yield strength of the material is exceeded, seizure may occur. The process of separation of wear products during meshing operation has a cyclic nature and occurs after a certain number of repeated deformations. The obtained results allow calculating the amount of wear of sliding friction surfaces [1].
Gas pyrolysis resin as a plasticizer for composite elastomer materials
Authors: Teshabaeva Elmira , Ergashova Hikoyat , Ahmadjonov Sardorbek , Abdullaev D. , Tursunaliyev Muxsinjon
Published: April 2023

The aim of the study is to study the effect of gas pyrolysis resin on the properties of elastomeric composite materials. It has been established that in the presence of it in the thiuram vulcanizing system, the relative rate of vulcanization of styrene-butadiene rubber increases, the time to reach the optimum vulcanization decreases, but the degree of vulcanization decreases, proportional to the maximum torque, and when using a sulfur vulcanizing system, it activates the vulcanization process, which is facilitated by the presence in its composition of active functional groups (-OH, -COOH, etc.). It is shown that the tensile strength and relative elongation of the vulcanizates increase, while the elasticity remains at an average level.
Evaluation of the results of the implementation of a product data management system in the technology department of a high-tech enterprise
Authors: Krivykh Aleksandra , Khvan Alexander
Published: April 2023

The technology department at any manufacturing enterprise is engaged in ensuring the release of new high-quality products on time with high economic efficiency. Depending on how successfully the technical department functions, the quality of technical documentation and, as a result, the quality of products depends. In this regard, it is necessary to constantly improve the efficiency of this department through the introduction of new management solutions, including those based on the use of modern software. This article discusses the process of introducing a product data management system into the technology department of a high-tech enterprise. A modified reengineering algorithm for the technical department is presented, functional modeling of business processes in the IDEF0 rotation is considered, and functional models are built. A small economic evaluation of the results of the implementation of the PDM system in the technology department is also carried out, and the results are presented. It is shown that the greatest effect of using a product data management system lies in two areas: reducing time to market and improving product quality. Thus, the introduction of the proposed system can significantly improve the quality of the production process not only in the department in question but throughout the enterprise.
Study of the profiles of the distribution of atoms of the contacting material over the depth of pure and ion-doped silicon
Authors: Donaev S.B. , Shirinov G.M. , Ergasheva S. , Rakhimov A.M. , Wang Shenghao , Abduvayitov A.A.
Published: April 2023

Auger electron spectroscopy combined with ion etching was used to study the effect of ion doping on the distribution profiles of atoms in silicon in contact with its surface. It has been established that preliminary implantation of Ba+ ions with E0=0.5-1 keV leads to a sharp decrease (by a factor of 10-12) in the diffusion length of oxygen and nickel atoms.
Analysis of the work, efficiency, and possibilities of constructive improvement of electrical air conditioning systems
Authors: Grishina L.A. , Pronin D.V.
Published: April 2023

This article discusses the main aspects of electrical air conditioning systems, as well as improving the efficiency of ESAC using the Boeing 787 as an example. In the course of the analysis, a comparative calculation was carried out according to the criterion of takeoff weight increment by the Bulaevsky-Shustrov method and its Western counterpart.
Research for reduction material-capacity of load-lift cranes with multi-engine electric drives on the base electromagnetic work shaft systems
Authors: Abidov K. , Dadajanov K. , Absoatov U. , Sabitov S.
Published: April 2023

This work is devoted to the study of multi-machine systems of coordinated rotation of the engines of handling equipment. The purpose of the work is to identify, by theoretical calculation, the reduction in the metal consumption of cranes equipped with multi-motor electric drives and operating on the principle of an electromagnetic working shaft, in comparison with the current ones. The analysis of the shifting moments of these systems in dynamics was made and conclusions were drawn about the reduction in the weight of the metal structures of cranes and the saving of metal in their production.
Determination of methods of achieving the energy savings through mathematical modeling of static and dynamic modes of electromagnetic energy conversion in asynchronous motors used in feed crushers
Authors: Pirmatov Nurali , Panoev Abdullo , Samatova G. , Berdiyorov O’lmasbek
Published: April 2023

The article covers the ways of achieving energy savings by controlling the speed of asynchronous electric motors in a frequency method. Frequency control is economical because it increases the efficiency and reduces power loss by adjusting the speed of the asynchronous motor.
Hydraulic energy storage of wind power plants
Authors: Urishev B. , Nosirov F. , Ruzikulova N.
Published: April 2023

The article discusses information on the need to accumulate energy from renewable sources to improve their efficiency, as well as some examples of the integration of systems for hydraulic energy storage and renewable sources, which ensure an increase in the reliability and volume of energy generation. The method for determining the parameters of the hydraulic energy storage system of a wind power plant, which is based on the balance of the daily load produced and spent on energy storage, is presented. This technique, with changing daily loads, makes it possible to determine the main parameters of the complex, including the volume of accumulated water, the coefficient of energy use of the wind power station. A functional diagram of the programmed control of the parameters of a pumped storage and wind power plant for the optimal use of the wind potential in hydraulic energy storage presented. Based on the results of calculations using the proposed method, the main parameters of the system based on a pumped storage and wind power plant with a capacity of 100 MW were determined, the efficiency of hydraulic energy storage was determined in comparison with lithium-ion batteries.
Experimental research of transition processes of asynchronous motors of belt conveyors on mathematical modeling
Authors: Abdiev O. , Bakieva Kh.
Published: April 2023

The purpose of the study. increasing the performance of belt conveyors and reducing transportation costs based on the developed mathematical modeling of transient processes of asynchronous motors of open-pit conveyor transport. The object of the research is the operating modes of asynchronous motors of belt conveyors of mining enterprises. The subject of research is the starting and braking modes of operation of asynchronous motors of belt conveyors of mining enterprises. Research methods are based on the modern theory of electrical machines, methods of linear and nonlinear mathematical programming, mathematical statistics, as well as methods of system analysis. The practical results of the study are as follows: the actual coefficient of resistance to the rotation of the conveyor rollers and the coefficient of resistance to the movement of the belt, leading to a decrease in the tractive effort, were determined; a method was developed for determining the additional power consumption of electric motors of belt conveyors, taking into account the overall volume, weight and speed of transported lumpy cargo; a mathematical model of braking and starting modes of induction motors of belt conveyors of mining enterprises was developed, taking into account the resistance coefficient of the belt and rollers.
Peculiarities of BaTiO3 in electronic and X-Ray analysis
Authors: Normuradov M.T. , Khozhiev Sh.T. , Akhmedova L.B. , Kosimov I.O. , Davlatov M.A. , Dovranov K.T.
Published: April 2023

We have studied the most promising material of semiconductor nanotechnology BaTiO3. Barium titanate, a compound of barium and titanate oxides, was studied in three dimensional varieties: in the form of powder with a diameter of 1÷1.5 mm, solid BaTiO3 target with a diameter of 76 mm and thin films obtained by ion-plasma sputtering with a thickness d ≈ 10÷50 nm, on the Si (III) surface. The spectra were recorded at room temperature on an XRD-6100 powder X-ray diffractometer, and spectra were taken from room temperature to 673 K, and the amorphous and crystalline phases of this substance were determined based on the obtained X-ray diffraction spectrograms. The peaks of the spectrogram based on the Miller indices and interplanar distances dhkl show complex compounds that are newly formed on the basis of barium titanate.
Three methods testing the asymmetry of the leaf blades of the small-leaved lime
Authors: Baranov Sergey , Zykov Igor , Poloskova Elena , Fedorova Liubov , Kuznezova Daria
Published: April 2023

Three methods were used to determine the fluctuating asymmetry (FA) of leaf blades and the developmental stability of smallleaved linden (Tilia cordata Mill): the normalizing difference method, the sample normalization method, and the two-factor analysis method (FA10). The collection of leaf blades took place along the latitudinal zonality gradient from north to south in five cities from Murmansk (68°58′ N) to Mozhaisk (55°30′ N), including the cities of Apatity, Petrozavodsk and Saint Petersburg. In all analyses, the highest FA value was obtained in the population of Petrozavodsk, the lowest in the population of Mozhaisk. In other cities, the FA indices differed, except for the populations in Apatity and Petrozavodsk with FA10 indices, respectively, 0.02 (p=0.02) and 0.03 (p=0.01). In the northernmost population (Murmansk), no decrease in developmental stability was noted. The stability of the development of Tilia cordata was more strongly influenced by the climatic and geographical conditions of the area and the technogenic state of the environment than by the geographic latitude. The authors note that a non-parametric sample distribution is advisable to use the two-factor analysis of variance, since normality difference and normalization lead to a non-equivalent deviation of the results. Bonferroni’s adjustments for measurement error were convenient for accurately distributing FA values at significance level.
Recycled strontium hexaferrite powder behavior in the magneto fluidized state in dependence of the chamber fill factor
Authors: Egorov Ivan , Egorov Nikolay , Egorova Svetlana
Published: April 2023

The magnetic powders affected by external magnetic fields can be transferred in the pseudo fluidized state to intensify the process of permanent magnets production. The behavior of the fluidized fine strontium hexaferrite powder with an average particle size 0.93 μm obtained by recycling old electric engine stators was studied. Mutually perpendicular constant and alternating gradient magnetic fields were used to form the magneto fluidized bed from the powder. The rheology state of the magnetic powder can be controlled by the parameters of the electromagnetic fields. The powder was affected by a constant field with induction values from 3 mT to 43 mT and alternating gradient magnetic field with induction gradient values from 87 mT/m to 317 mT/m. The chamber bulk fill varied from 4% to 100%. To study the rheological state of the powder in the chamber, we used an inductive method – an inductive coil was put on the chamber and the moving powder particles induced the current in the coil. The values of the current allowed to estimate the mobility of the powder particles in the magneto fluidized bed. The paper presents the results of experimental studies how electromagnetic fields regimes influences on the rheology of the fluidized powder. Methods of choosing the fields regimes providing the rheological state optimal for the required technological process depending on the chamber fill factor are described.
Recycling in the production of mineral wool
Authors: Alpackiy Dmitriy
Published: April 2023

The main heat-insulating material used in Russia is mineral wool. One of the problems of waste reclamation of mineral wool products is returning of chips and globules back to the solid fuel furnace. To solve the problem, it is proposed to briquette waste before feeding it into the furnace. The author suggests using alumina cements of Russian production as a binder. The choice of the binder is conditioned by the chemical composition of the cement. The second factor that was considered when choosing the binding material was its strength in the early stages. Samples of a mixture of waste and binder were pressed into cylinders and then heat treated for an hour. As a result of the study, the dependences of the impact strength of the samples on steam curing temperature and the humidity of the samples have been obtained. It has been revealed that an increase in humidity has a greater effect on the rise in impact strength than an increase in temperature. Results: the dependence of the impact strength of briquettes made of the mineral wool industry waste and alumina cement on humidity and curing temperature has been revealed, which will make it possible to select optimal conditions for returning of waste to the furnace.
Obtaining nickel nanoparticles by the gas-phase method - induction flow levitation
Authors: Markov Artyom , Kapinos Alexander , Emelyanov Artyom , Kleiman Grigory , Dokin Yegor , Grachev Pavel , Zanozin Ivan , Petukhov Anton , Vorotyntsev Andrey
Published: April 2023

In this paper, we consider the possibility of obtaining nickel nanoparticles from a bulk sample by the method of induction flow levitation. This method is based on non-contact heating and holding a metal sample in a state of levitation by a high-frequency electromagnetic field. The generator power was 10 kW and the frequency was 440 kHz. The synthesis took place at a temperature of 1800°C with a feeding rate of 3 g/h. Argon was used as the refrigerant gas, the pressure in the system was maintained at 400 mbar. The resulting nanoparticles were characterized by size using SEM and TEM micrographs, where the average size of the nanoparticles was ~16 nm. XRF and SEM-EDS, the results showed the presence of only metallic nickel and oxygen in the nanoparticles.