bluuebunny/crossref_metadata_2025_split huggingface dataset:
The periodic temperature oscillations in the near-surface layer of cylindrical structures
Authors: Samarin O D 
Published: September 2020

Abstract
A hollow cylinder with thick walls and linear continuously acting variable heat sources are among the most difficult objects to calculate the unsteady temperature field, so this field is the least studied. However, such objects are found in many modern designs of heat generation and distribution systems. The proposed work considers the study of the temperature wave propagation in the wall of a hollow cylinder and in a cylindrical symmetric array around a variable linear heat source with a harmonious change in the temperature of the external or internal environment that occurs during its daily fluctuations or when regulating the heat distribution system. The result of approximate analytical solution of the problem by the method of separation of variables in the complex domain using cylindrical functions is presented. The data of numerical calculation of attenuation of temperature oscillations in the near-surface layer of the cylinder and around the variable linear heat source by means of an explicit finite-difference scheme of increased accuracy under boundary conditions of the first kind and their comparison with the analytical solution for its refinement are presented. The refined analytical dependences for the attenuation coefficient of the temperature wave suitable for use at low thermal inertia of the cylindrical layer and giving physically correct results at the boundary values of the parameters are proposed. The difference in the nature of the damping of oscillations in the direction of the temperature wave outside and inside the cylinder is noted. The presented dependences are proposed to be used for a refined analytical assessment of the amplitude of temperature fluctuations in the near-surface layer of cylindrical heated structures and around the heating and heat supply pipelines in variable modes, which will allow the use of engineering methods to verify compliance with the requirements of industrial safety.
Calculating the load on the room cooling ceiling panel at solar heat gains
Authors: Malyavina E G , Lomakin A G 
Published: September 2020

Abstract
It is known from the theory of heat exchange that for the assimilation of the room heat gains that are not constant in time, a cold flow of the same nature that assimilates them must be equal to them in magnitude. This is obvious with respect to convective heat gains that introduce directly into the air. The case is more difficult with the radiant heat gains, since the incoming radiant flow can be directed to one surface, and the assimilating one comes from another. The article aims to check to what extent this provision plays a role in the realities of maintaining a given room microclimate. However, in engineering practice, there are no purely radiant heat assimilating systems. Therefore, as a room cooling system, a ceiling cooling panel has been used, the heat flow from which is of a radiant-convective nature. The radiant load of the room occurred from the solar radiation, penetrating through the windows of various orientations on the cardinal directions. Determination of the load on the cooling system was performed by calculation. Based on the results of the calculation, it was found that the load on the ceiling panel significantly depends on the internal heat stability of the room.
Elastomeric fire and heat-protective materials containing zirconium dioxide
Authors: Kablov V F , Novopol’tseva O M , Kryukova D A , Antonov Y M , Kochetkov V G 
Published: September 2020

Abstract
Elastomeric fire-protective materials are widely used to protect special-propose structure in rocket, aviation and marine equipment. Important parameters of such materials are density and thermal conductivity. The reduction of these indicators while maintaining the rest of the set of materials properties is a complex and multifactorial task. A promising direction of its solution is the use of microspheres. The work shows that it is possible to increase the fire protection efficiency of elastomeric compositions, which contain transition metal oxides, with zirconium dioxide as an example. The effect of the introduction of zirconium dioxide in the form of a microdisperse powder, microspheres, and zirconium-aluminosilicate microfibers on the physical and mechanical, thermophysical, and fire protective properties of elastomeric compositions based on ethylene propylenediene rubber has also been considered.
Thermotechnical calculation of enclosing structures of a standard type residential building
Authors: Gamayunova O , Petrichenko M , Mottaeva A 
Published: September 2020

Abstract
Russia has extensive experience in the design and construction of typical series of residential apartment buildings. When there is a library of standard projects for which additional expertise is not required, this significantly reduces both the price and the construction time of the facilities. Accordingly, the cost per square meter is reduced. Currently, to reduce the cost of construction, some developers use enclosing structures made of materials with high thermal conductivity, thereby reducing the energy efficiency of buildings and structures. In this article, on the example of houses of mass series 1-447, the thermotechnical calculation of enclosing structures was carried out and the option of the optimal position of the insulation was determined. The temperature distribution of the building envelope is presented.
Studies of Freon mixture separation using a large-scale model of distillation column
Authors: Pavlenko A N , Zhukov V E , Slesareva E Yu , Boyadjiev Chr , Dzhonova-Atanasova D 
Published: September 2020

Abstract
The operation efficiency of distillation columns with structured packing is maximal if the distribution of countercurrent vapor and liquid film flows over the column cross-section on the mass transfer surface is most uniform. Various types of structured packing are widely used in distillation columns. Formation of the temperature field maldistribution in the column cross-section is observed in large-scale distillation columns. The sizes of large-scale maldistributions on zones are commensurate with the column diameter. The aim of this work is to obtain experimental data on the separation efficiency in large-scale distillation columns and dynamics of formation of large-scale maldistributions of local parameters of vapor and liquid in a countercurrent flow over a structured packing during mixture separation. Separation of the R114/R21 freon mixture was carried out on a structured Mellapack 350.Y packing with a diameter of 0.9 m and height of 2100 mm. The experiments were carried out under conditions of complete reflux in the range of reduced vapor velocity of 0.017 < K
v < 0.035 m/s. Experimental data were obtained on the efficiency of mixture separation, pressure drop over the structured packing and parameters determining the formation dynamics of the large-scale temperature field maldistribution in the column cross-section. The presented experimental data will be used for the construction and verification of a new model of mass transfer and efficiency of mixture separation in large-scale distillation packed columns.
Modernization of the heat pump installation for drying wheat
Authors: Kizurov A S 
Published: September 2020

Abstract
The most energy-consuming and most critical stage of post-harvest processing is grain drying. Safety of grain depends on its drying. For drying grain, grain drying plants are used that remove excess moisture from the grain. In most cases, drying occurs under the influence of elevated temperatures with a constant supply of heat. After drying, the grain must be cooled to eliminate irreversible processes. The drying process is slow due to temperature limitations. To speed up the drying process, various techniques are used, one of which is the alternation of heating and cooling processes (differentiation of heat input). To increase the drying energy efficiency in the conditions of differentiation of the supply of thermal energy, it is advisable to use heat pump units. Heat pump units allow the creation of a heating agent (heated air) and a cooling agent (cooled air). Studies have shown that for different grain parameters, different temperature characteristics of heating and cooling agents are required. For independent temperature control of heating and cooling agents, an original design of a heat pump installation has been developed. To automate the control of the drying process, several control schemes have been developed and investigated.
Modeling the change of water content in wood at atmospheric drying
Authors: Zaitseva M , Nikonova J , Kolesnikov G 
Published: September 2020

Abstract
Objective: to develop a methodology for predicting changes in the water content in wood during atmospheric drying, taking into account the fast and slow stages of this process. Research methods: mathematical modeling, applied analysis of results, comparison with experimental data known from the literature, synthesis in order to better understand the regularities of drying. Results: a two-parameter model is developed, in which a phenomenological approach is used, focused on obtaining averaged estimates of wood moisture during atmospheric drying. Causal relationships are not detailed, but are taken into account in an integral form. Calculation formulas are obtained, the use of which simplifies the procedure for predicting changes in the water content in wood during atmospheric drying. The adequacy of the model and the reliability of the calculation results are confirmed by their consistency with the experimental data known in the literature. Research prospects can be focused on adapting the model to other drying methods in order to reduce the energy and time spent on a given technological process.
Characterization of rainfall events corresponding to forecasted conditions of potential hydrogeological risk
Authors: Khramtsova L , Leonteva M , Mobilia M , Longobardi A , Nasyrova E , Aksenov S 
Published: September 2020

Abstract
The Italian territory has a high exposure to natural risks including floods and landslides. An early warning system run by the Department for Civil Protection, both at national and regional level, operates to forecasted conditions of potential hydrogeological risk on the basis of forecasted meteorological conditions. The aim of the present paper is to study the relationship between the level of alert issued by the Civil Protection and the characteristics of the associated rainfall events. The case study is a particular area of the Campania region, highly prone to hydrogeological risk. A database of 138 warnings issued during the period 2018-2019 has been analyzed. The warnings were classified using analytical and graphical methods with various criteria. The duration, total rainfall, peak intensity, return period, n-index, BSC-index were used. The results show that there is a clear correlation between the severity of the warnings and the cumulative, peak intensity and the structure of precipitation. No relationship has instead been found between the severity of the warnings and the severity of the rainfall event which, besides the limitation of the case study with a small sample of analyzed events, can be an indication of changing climate conditions.
Comparative analysis for three models of hysteretic water retention capacity using data on silty soil
Authors: Lazarev V A , Ginevsky R S , Topaj A G , Nikonorov A O , Dunaieva I A , Terleeva A V 
Published: September 2020

Abstract
The most important of the hydrophysical properties is the water-retention capacity of the soil. This property is formulated as a relationship between the volumetric moisture of the soil and the capillary pressure of soil moisture. Three hysteresis models of soil water-retention capacity are presented. The parameters were identified by point approximation of experimental data (from an authoritative literary source) on the main (boundary) drying and wetting branches of the soil «2003 Silt of Nave-Yaar» using the «SoilHysteresis-v.1.0» computer program developed by the authors. Applying the condition of equality of the values of the exponential parameter for the branches of draining and moistening eliminates the undesirable (methodical) «pump effect». A comparative analysis of hysteresis models based on the identification of significant differences between the errors of the point approximation of the experimental data by the Williams-Kloot test. The advantages of models in which an additional additive parameter is used are revealed. The use of physically justified models of hysteresis of the water-retention capacity of the soil has prospects in the development and application of resource-saving technologies in precision reclamation agriculture.
The effect of snow covers properties and air temperature on the ice freezing thickness near Yakutsk
Authors: Frolov D 
Published: September 2020

Abstract
This study is devoted to the possible Yakutsk Lena–river automobile and railway bridge construction and estimation of icing and ice blockage formation possibility variation. So, according to developed algorithm and calculating scheme the calculations of ice freezing thickness variations for observation site of Yakutsk Lena-river hydrological station were performed on basis of meteorological data on air temperature and snow cover thickness for winter periods of 1980/81-2018/19. The comparison of calculated and available in open access observation data on ice freezing thickness for these winter periods was also conducted and the coefficient of correlation of equal 0.7-0.8 for them was stated. The calculating scheme for ice freezing is constructed on basis of two-layer media heat conductivity problem (snow cover, ice) with phase transition on the boundary of ice and unfrozen water. Heat balance equation includes phase transition energy on the interface and outflow of heat through ice and snow cover into the atmosphere. The heat flux is calculated on basis of Fourier law as a product of heat conductivity and temperature gradient. It is supposed, that temperature changes in each media linearly.
Modeling static characteristics of angular velocity measuring transducer of the “nozzle-damper” type
Authors: Golubovsky V , Konovalov V , Doncova M 
Published: September 2020

Abstract
The article describes the design and principle of operation of the hydraulic measuring transducer of angular velocity of the “nozzle-damper” type. The aim of the study is the mathematical modeling in the MathCAD program of the static characteristics (flow and differential) of the measuring transducer, based on the Bernoulli equation. The research methodology provides a theoretical justification of the proposed expressions describing the operation of the transducer, analysis of numerical results obtained by numerical modeling in the MathCAD program, and their verification by comparison with experimental data. The developed mathematical model based on the Bernoulli fluid equation of motion, taking into account the use of the proposed correction factors, allows one to adequately describe the static characteristics of the angular velocity measuring transducer of the “nozzle-damper” type. According to the numerical values of the statistical criteria, the proposed power-law model more accurately describes the experimental data than the linear model. At a supply pressure of the measuring transducer equal to and less than 0.5 MPa, a discrepancy between the results of the model and experiments is observed.
Development of an automatic method for determining vehicle dimensions through computer vision
Authors: Baytesh K , Gematudinov R G , Chantieva M E , Dzhabrailov K A , Gorodnichev M G 
Published: September 2020

Abstract
This article has a system of automatic weight and dimensional control (weight - and - motion), which allows weighing, measuring geometric characteristics, as well as recognition of state registration plates, passing vehicles without stopping, as well as processing of this data and registered violators. The focus is on the work of measuring the mass along the axes. All conversions are performed on the National Instruments multifunction board, which has a microcontroller, additional I/O peripherals field-programmable gate array, which means user-programmable gate arrays. In a more general case, they are called FPGAs - programmable logic integrated circuits. This study is important because heavy vehicles smash federal and local roads. Therefore, it is necessary to control the passage, however, now this measurement is carried out only in static mode. Measurement of dimensions in dynamics based on piezoelectric elements has an error unacceptable by the legislation of the Russian Federation. The developed method will increase the accuracy, which will lead to a mass measurement of dimensions, and will allow to maintain in good condition the roads of federal and local destination.
Modeling the stress state of a rotating flexible thread (cable) to optimize its speed
Authors: Tarasov D , Konovalov V , Zaitsev V 
Published: September 2020

Abstract
The aim of this work was to develop and verify the operability of the method to determine the maximum permissible rotation frequency of a flexible thread (cable), at which a centrifugal inertia force arises, causing stresses and strains not exceeding the permissible limits. Based on the selected assumptions, the research methodology provides for the development of a method of analytical strength calculation of a rotating cable. The resulting system of expressions is the basis for the development of a computer program to be checked for operability by the accuracy of calculations. The calculation method, reflected in the form of a flowchart and implemented as a computer program, allows determining the maximum possible frequency of rotation of a cable that does not allow its limit state to occur, which will simplify the search for the optimal solution and reduce the time spent. Solving the nonlinear programming problem of determining the frequency of rotation of a cable taking into account the development zone of plastic strains in the material at the given maximum permissible stresses and strains by reducing it to the problem of unconditional optimization using Lagrange multipliers allows us to calculate with an error of not more than 4% compared with the FEM. The calculation results make it possible to use the proposed method both when there is a restriction on the strength condition (allowable stresses) of the material of the cable, and on the allowable deflection in the middle of the span of the cable.
Verification of the iterative procedure for solving the elastoplastic Kirsch problem on the Lame problem
Authors: Bukhalov V I , Popov A L 
Published: September 2020

Abstract
An iterative procedure for solving the elastoplastic Lame problem was proposed to further develop an iterative solution of the elastoplastic Kirsch problem. A ring under an external pressure is considered at which a certain plastic zone arises in the ring. The proposed iterative procedure for solving the elastoplastic Lame problem consists in an explicit analytical representation for stresses in the plastic region and the iterative technique for an elastic analytical solution. Furthermore, the plastic zone radius is beforehand unknown. The convergence of the iterative procedure for the elastoplastic Lame problem is shown in comparison with well-known analytical solution to this problem in elastoplastic formulation. A numerical-analytical iterative solution of the Lame problem in elastoplastic formulation is given for various external pressure and internal radius of the ring. Shows the convergence of numerical-analytical iterative solutions the problem in comparison with numerical solutions in elastoplastic formulation.
On estimates of computational complexity and error of the fast algorithm in the vortex methods
Authors: Kuzmina K S , Moreva V S 
Published: September 2020

Abstract
One of the efficient ways to speedup calculations in the vortex method, namely the Barnes – Hut-type algorithm, is considered. This method is based on the introducing of a hierarchical structure of domains (binary tree), which allows one to take into account approximately mutual influences of clusters of vortex elements located far from each other when calculating convective velocities. Estimates of the computational complexity of the algorithm for convective velocities calculating are derived, as well as estimates of the error, which depend on the parameters of the algorithm. In practice, these estimates make it possible to choose optimal values of the algorithm parameters and to achieve the maximal speedup of calculations at a given level of acceptable calculation error.
Qualitative assessment of passenger service
Authors: Anikin N , Terentyev V , Andreev K , Shemyakin A , Martynushkin A 
Published: September 2020

Abstract
The developed methodology for assessing the level of quality of passenger service presented below is relied on existing developments in this area, international standards for determining the quality of service and passengers’ questionnaire. The main goal of the proposed methodology is to determine the necessary social effect of the urban passenger transport, as well as the costs that must be incurred to ensure it and the income that will be received at a given level of service for the population of the city (region). When determining all these indicators, it is necessary to take into account the interests of all participants in the passenger service market (urbanities, owners of private motor transport enterprises and passengers). According to the methodology, it is proposed to determine the social effect of the urban transport through the level of quality of passenger service. This indicator should include both the qualitative characteristics of passenger service and the level of transport tariffs of different carriers, since for many categories of passengers, the latter indicator will play a decisive role in choosing the type of the vehicle and the carrier.
The effect of networks cracks on the strength of pavement
Authors: Rudgalskiy P , Chusov V , Aleksandrova N 
Published: September 2020

Abstract
The analysis of the methodology for determining the coefficient of strength of pavement, based on the results of a visual assessment of the condition of pavement is performed. The traditional classification of the networks of cracks is considered, and the reasons for their arising on the Bolshie Uki - Znamenskoe road are analyzed. Traditional fatigue cracking and temperature tensile stresses are defined as main causes of cracks network. The feature of the emergence of networks of cracks on the pavement of the road Bolshie Uki - Znamenskoe, which consists in the appearance of these defects in sectors located on terrain with long standing groundwater, is revealed. Therefore, as a related cause of the appearance of a network of cracks, the effect of insufficient strength of a subgrade of cohesive soils and increased humidity was noted. Experimental work was carried out to determine the elastic deflections in the sectors with networks of cracks and the reference sector without defects. According to the experimental work, safety factors are determined, and mathematical models of the dependence of the coefficient of strength from the cell size of the cracks network are developed.