bluuebunny/crossref_metadata_2025 huggingface dataset:
Mid-Level Personnel in the Finno-Ugric Republics of the RSFSR in the mid-1950s – mid 1970s: Proportion within the Total Number of Workers and Employees
Authors: Matsuk Alexander M.
Published: October 2024

Introduction. The processes of reforming the education system in the USSR in the second half of the 1950s – early 1960s had a certain impact on the system of secondary specialized education, including in the Finno-Ugric republics of the RSFSR. This, in turn, affected the dynamics of saturation of the national economy with mid-level personnel. The aim of the study is to examine the dynamics of the number of specialists with secondary vocational education and their proportion among all workers and employees within the specified territory in the context of the ongoing education reform and in the subsequent years.
Materials and Methods. The basis of the research presented in the article was statistical data that made it possible to trace the dynamics of changes in the number of mid-level specialists and their share in the national economy of the Finno-Ugric Republics of the RSFSR in the mid-1950s – mid-1970s. The research is based on comparative historical and systematic approaches, using the method of statistical information analysis.
Results and Discussion. The conducted study of the dynamics of changes in the number and proportion of middle-level specialists with secondary specialized education in the national economy of the five Finno-Ugric republics of the RSFSR revealed a positive trend that persisted throughout the studied period. The overall growth in the number of middle-level specialists was recorded at more than 4 times. The proportion of this group in the total number of workers and employees increased by more than 6%. Available statistical data showed the highest growth both in terms of number and proportion of these specialists in the early years of the education reform in the country, when there was a maximum influx of graduates who had completed their education before the reform. From 1960 to 1965, the dynamics of these indicators significantly slowed down, indicating the impact of negative factors from the ongoing reform. In the post-reform period, there was an observed acceleration in the growth rate of both the number and proportion of middle-level specialists.
Conclusion. The results obtained from this study can be used both as a basis for examining issues related to state policy on staffing the national economy with professional personnel during the specified period and for researching the history of the system of secondary specialized education in general. The general patterns identified in the study regarding changes in the number of mid-level staff employed in the national economy of the five Finno-Ugric republics of the RSFSR from 1955 to 1975, as well as the noted peculiarities of this process in individual republics against the backdrop of educational reforms in the country and the post-reform years, allow for further analysis of similar processes in other regions of the country.
Chapel of the Nativity of the Lovozersky Sami Churchyard
Authors: Shakhnovitch Mark M. , Kolivatov Evgeniy B.
Published: October 2024

Introduction. The article considers the discovery of a unique object in the Lovozero tundra – the chapel of the Lyavozersky churchyard on Lake Chesynyavr. Monuments of Orthodox Sami culture in the Murmansk region have rarely been studied by specialists The purpose of the study is to introduce into the research circulation the information about existing documents on the history of the chapel, the results of expeditionary work on its survey, and to continue the discussion about the time of construction and the stages of history.
Materials and Methods. The research was based on archival documents and expedition materials. The research is based on the principle of historicism using the comparative historical method.
Results and Discussion. The chapel was found in 2002. Expeditions to study it took place in 2016 and 2019. The first documentary report specifically about this monument dates back to 1828. After the change of the site of the winter churchyard of the Semiostrovsky Sami, the chapel was not moved along with the dwellings and remained "in the forest". With the formation of the Lovozersky churchyard, it reappears in official documents, already being called the Chapel of the Nativity. In 1895, it was expanded and renovated. It was abandoned in the 1930s.
Conclusions. When analyzing archival documents, it is suggested that the chapel was built in 1681. Its history can be traced back to the 1930s. According to the authors, the thesis of the "dual faith" of the Sami, which has been formed in the regional literature, requires revision. The fact of the existence of an Orthodox chapel in the Lovozersk tundra speaks about the stable Christian worldview of the indigenous population of this part of the Kola Peninsula.
Effect of low temperatures on shrimp quality
Authors: Strateva M.
Published: October 2024

Abstract. Shrimp is one of the most preferred seafood for consumption. The high water content and nutrients place shrimp in the category of perishable fast spoiling foods. In order to avoid deterioration of their quality, it is necessary to freeze and store them at low temperatures. Fluctuations in temperature can cause thawing and refreezing with recrystallization. In frozen products, the amount and size of ice crystals play a major role in the quality of these products. Despite the wide application of freezing, various histological, physicochemical, microbiological, enzymes and pH changes occur with varying degrees of manifestation. The objective of the review was to discuss the effect of freezing on the quality of shrimp used for human consumption.
Az okostelefon alkalmazásának hatása testnevelésórán
Authors: Varga Attila , Révész László
Published: October 2024

Háttér és célkitűzések: Jelen tanulmányban azt vizsgálták a szerzők, hogy a testnevelésórai okostelefon-használat hogyan hat a pszichomotoros teljesítményre, az észlelt motivációs környezetre, valamint a motivációra. Egy négyhetes időtartamú intervenciós program keretében használhattak okostelefont a tanulók testnevelésórán. A kutatás célja annak felmérése volt, hogy az okostelefon-alkalmazás milyen hatást gyakorol a teljesítményre és a motivációra. Módszer: A kutatásban középiskolás tanulók vettek részt (n = 85). 21 fiú (24,7%) és 64 lány (75,3%), az átlagéletkoruk 16,7 év volt. A kutatás során a tanulók egy 12 tanórás projektben vettek részt, ahol a kísérleti 1 csoport okostelefont használhatott, míg a kísérleti 2 csoportban nem volt eszközhasználatra lehetőség. A vizsgálat során 20 m-es ingafutás teszttel (pszichomotoros, állóképességi teszt) vizsgálták a kutatók a teljesítmény változását, az Észlelt Motivációs Környezet a Sportban (Perceived Motivational Climate in Sport Quiestionnaire-2/PMCSQ-2) kérdőívvel az észlelt motivációs környezet alakulását, míg a motiváció változását a Sport Motivációs Skálával (Sport Motivational Scale/SMS). Eredmények: Az eredmények azt mutatják, hogy abban a csoportban, ahol okostelefont használtak a tanulók, jelentősen javult a teljesítményük, a tanulók az intervenció során egyre nagyobb távokat teljesítettek a futások alkalmával, illetve egyre hosszabb időt is választottak. A tanulók feladatorientációja, valamint az intrinzik motivációja is növekedett. Az okostelefont nem használó csoportban is javult a teljesítmény az intervenció hatására, ugyanakkor az volt tapasztalható, hogy az Ego (én) orientáció növekedett, illetve nőtt a motivációhiány is a projekt végére. Következtetések: Az eredmények alapján elmondható, hogy a testnevelés tanításában pozitív hatása van az eszközhasználatnak, növeli a tanulók teljesítményét, valamint motivációjukat.
Income convergence in Central and Eastern Europe: Evidence from cross-country panel data analysis
Authors: Alemu Seboka , Udvari Beáta , Kotosz Balázs
Published: October 2024

Recent research has suggested that unconditional convergence no longer exists. Thus, this study examined the income convergence among 11 Central and Eastern European (CEE-11) countries that joined the European Union in/after 2004 and Europe's four largest economies (Germany, France, the United Kingdom, and Italy) by using panel data from 1994 to 2019. For this purpose, it employed the beta (β) and sigma (σ) convergence approaches to analyze the dynamics of economic growth. Based on the findings, in 1996, the four largest European economies had a higher capital–labour ratio and GDP growth than CEE-11. However, by 2019, the patterns reversed. As for the regression results, there was strong evidence of unconditional β convergence between 1999 and 2019, at an annual rate of 11%, with the σ convergence and the fixed effect models further supporting income convergence. Moreover, although brief divergence occurred during various financial crises, the overall trend was a significant convergence of CEE-11 with Europe's four largest economies through higher relative GDP growth. This study contributes to the economic growth theory of income convergence across countries and highlights the importance of regional integration in enabling sustainable catch-up growth.
FACTORS AFFECTING THE INCOME OF FISHERMEN OF SERAYA ISLAND BATAM CITY IN THE SPAWNING SEASON OF DINGKIS (Siganus sp.)
Authors: Hafsar Khairul , Novedri Muhamad Nazri , Ulfah Fitria
Published: October 2024

One of the fish commodities that has great potential to be utilized by the fishermen of Seraya Island is Dingkis (Siganus sp.). During the spawning season, Dingkis experience a high price increase of 5 times the price during the non-spawning season, namely IDR 30,000-60,000/kg. Therefore, Seraya Island fishermen take advantage of this opportunity because Dingkis fish only spawn during a certain season, namely January-February, which coincides with Chinese New Year (Imlek). The aim of the research is to determine the income of Seraya Island fishermen during the Dingkis spawning season and the influence of the price of Dingkis, the number of Dingkis fish caught, and the number of other fish catches on the income of Seraya Island fishermen. The research was conducted on Seraya Island, Batu Legong Village, Bulang District, Batam City in February 2023. Data analysis was used to answer the first objective, namely by calculating income, the second objective was to test the influence of the independent variable on the dependent variable using SPSS type 26 software. The research results show that the average income of Seraya Island fishermen during the Dingkis spawning season is IDR 9,001,143/month. Partial test results on the number of catches of Dingkis fish have an effect on the income of Seraya Island fishermen. The price of Dingkis fish and the number of other fish caught have no influence on the income of Seraya Island fishermen.
ENVIRONMENTAL SUITABILITY, PLANTING DENSITY AND INDUSTRIAL PERFORMANCE OF INTENSIVE VANAME (Penaeus vaname ) FISHING IN PONDS
Authors: Farkan Mochammad , Sektiana Sinar Pagi , Nurraditya Lakonardi , Pamaharyani Luchiandini Ika , Lathifah Firyal
Published: October 2024

Shrimp is one of the leading commodities with high economic value and generates foreign exchange in local and international markets. The production of shrimp farming industry in ponds fluctuates, causing doubts for investors and practitioners to develop shrimp farming in ponds. The weakness is that there is no available data on the evaluation of aquaculture performance as a good shrimp farming planning material. The purpose of this study was to assess the performance of shrimp farming industry in intensive pond system. The research was conducted from September 2023 to February 2024. The research location was Rhee Royal Vannamei Sumbawa West Nusa Tenggara, Indonesia. This research is applied research with data collection methods are observation and quantitative.  Data processing using Microsoft excel and SPSS (Statistical Program for Social Science). The results showed that the land is suitable for vaname shrimp farming, performance analysis showed Average daily growth (ADG) 0.4 gr/day, Average body weight (ABW) 13.86+5.59 g/head, Survival Rate (SR) 55+25%, Food Conversation Ratio (FCR) 1-1.5, and Productivity 11+5 tonnes/ha. The relationship between stocking density and shrimp productivity was not significant. Five cycles of production fluctuate, so it is not possible to determine predictions for the coming year. The prospect of shrimp farming industry in ponds is good enough to improve the economy.
Food and Drink at the Restoration, as seen through the diary, 1660-1669, of Samuel Pepys
Authors: Lehmann Gilly
Published: October 2024

The author employed computational analysis techniques in a study of what Samuel Pepys says in his diaries that  he consumed between 1660-1669.
From Espinee to Sambocade
Authors: Hieatt Constance B , Hosington Brenda M
Published: October 2024

The article looks at one of the differences between medieval French and English recipes in the early middle ages finding that in the latter cuisine, flowers as appear as ingredients rather than mere decoration.
DYNAMIC STABILITY OF A STRAIGHT PIPE CONVEYING PULSATILE FLOW UNDER THERMAL LOADS
Authors: Lolov D. S. , Lilkova-Markova Sv. V.
Published: October 2024

Pipes conveying fluid are considered as a fundamental dynamical problem in the field of fluid- structure interaction. They are widely used in the petroleum industry, in nuclear engineering, aviation and aerospace, in nanostructures. This article investigates the effect of temperature load on the dynamic stability of a straight pipe conveying pulsatile flow. The fluid velocity is a harmonic function of time. The Galerkin method is applied for the solution of the differential equation of the transverse vibrations of the pipe. The differential equation is reduced to a first-order differential equation system. The system of differential equations is transformed and rewritten in a matrix form. The harmonic function of the fluid velocity allows the Floquet theory to be applied in order to investigate the dynamic stability of the system. The static scheme of the investigated pipe is a beam with restricted horizontal and vertical displacements at both of its ends. A numerical solution for a straight pipe conveying fluid with specified geometric and physical characteristics has been carried out. The temperature load and the constant fluid rate are considered as parameters of the problem. The results show that the temperature load affects the vibrational characteristics of the pipe, as well as its critical velocity.
FINITE-STRAIN ELASTIC-PLASTIC TORSION: ANALYTICAL AND FEM MODELING FOR NONMONOTONICALLY HARDENING POLYMERS
Authors: Sevastyanov G. M. , Bormotin K. S.
Published: October 2024

Polymeric materials, depending on the structure and chemical composition, exhibit various types of isotropic strain hardening. In particular, in the range of plastic deformation on the "true strain – true stress" curve, there may be a descending section of softening caused by the weakening of intermolecular bonds. This softening region is further replaced by a power-law hardening. The laws of deformation of materials can be established from simple experiments, one of which is often torsion. For torsion of thin-walled cylindrical specimens, the stress-strain state is practically uniform; therefore, such experiments are easy to interpret. However, stability problems arise at large deformations of thin-walled specimens. For solid cylindrical specimens, the stress state is inhomogeneous; interpretation of such experiments is possible on the basis of FEM modeling or using exact or approximate analytical solutions of the corresponding initial-boundary value problems of mechanics. In the present study, an exact analytical solution of the elastic-plastic problem of torsion of a cylindrical sample is presented, which is valid for an arbitrary law of isotropic hardening. The multiplicative decomposition is utilized as the kinematics of elastic-plastic deformation. The non-linear elastic properties of the material are described by the Mooney – Rivlin model. In the plasticity condition, the Tresca equivalent stress is used, which makes it possible to obtain a closed solution. The integral characteristics of the process (torque and axial force that represents a second order effect) are calculated. The analytical results are compared with the results of numerical simulations in MSC.Marc, as well as with the available experimental data. The analytical solution for torque corresponds very closely to the numerical solution obtained by the finite element method. Also, the curves of axial force coincide satisfactorily. At moderate strains, the analytical solution accurately describes the experimental results.
ANALYSIS OF METHODS FOR CONSTRUCTING TRUE DEFORMATION DIAGRAMS OF ELASTOPLASTIC MATERIALS UNDER LARGE DEFORMATIONS
Authors: Bazhenov V. G. , Kazakov D. A. , Kukanov S. S. , Osetrov D. L. , Ryabov A. A.
Published: October 2024

To study the deformation and strength properties of materials, it is important to use an experimental and computational approach that allows taking into account the ununiaxiality and heterogeneity of the stress-strain state without accepting simplifying hypotheses. True deformation diagrams are constructed using an iterative procedure of updating the strain intensity– stress intensity relation proportionally to the relative difference in the values of axial forces as obtained numerically and experimentally for an inhomogeneous stress-strain state, accounting for necking, up to rupture. The procedure requires multiple solutions of the problem, which is a time-consuming computational task. Two scenarios of analyzing the boundary-value problem are considered. The first scenario involves analyzing the entire direct problem over the whole loading interval; in the second one, the entire loading process is subdivided into several intervals defined by discrete values of an experimentally found generalized displacement–generalized force relation. At each small interval, a deformation diagram is constructed, using a nonlinear extrapolation procedure. At the end of each interval, the difference between the calculated and experimentally determined generalized forces is checked, and the stress intensity value is iteratively updated. The presented numerical studies show that constructing a deformation diagram with accuracy less than 1% according to the first scenario required 5–10 repeated analyses of the direct problem, whereas in the second scenario not more than two direct analyses suffice. Monotonous convergence and computational efficiency of the proposed iterative algorithms are shown for a number of tasks: stretching solid cylindrical rods and bolts M8 with smooth and threaded working parts. Based on the experimental and computational approach, the true deformation diagrams for steels 12H18N10T, 10HSND and St35 up to destruction are determined.
INVESTIGATION OF THE ELECTRO-MAGNETO-ELASTIC STATE OF A FINITE MULTIPLY CONNECTED THIN PLATE
Authors: Kaloerov S. A. , Seroshtanov A. V.
Published: October 2024

The problem of bending a finite plate with arbitrary holes and cracks is solved with the use of complex potentials of the theory of bending of thin electro-magneto-elastic plates. Moreover, with the help of conformal mappings, expansion of holomorphic functions into the Laurent series or Faber polynomials owing to satisfaction of boundary conditions on the contours of the plate by the generalized least squares method, the problem is reduced to solving an overdetermined system of linear algebraic equations by the method of singular value decompositions. Results of numerical investigations for a circular plate with a circular hole, for a circular plate with an internal or edge crack, for a plate with a two circular internal holes or external recesses are reported. We study how physical and mechanical properties of the plate material and geometric characteristics of holes, cracks and recesses influence the values of the bending moments and moments intensity factors for the crack ends. It is important to consider the piezoproperties of the material on the values of bending moments in the plate. They cannot be neglected in the study of the stressstrain state, that is, it is necessary to solve the problem of electro-magneto-elasticity, and not the problem of the classical theory of bending of an anisotropic plate. Moreover under the electromagnetic field in the piezoelectric plate there are sufficiently large bending moments (hence stresses and deformations), and they can be found only by solving the problem of electromagneto- elasticity. It is determined that a crack in a plate can be considered as an elliptical hole, in which the ratio of the semiaxes is less than 10–3, and in these cases it is possible to calculate the intensity factors of mechanical and electromagnetic moments. We also outline the distances between the contours, which have an insignificant influence of one of them on the stress-strain state around the other and can be neglected.
STUDYING GRAPHENE ELECTROMECHANICAL BEHAVIOR BASED ON THE ELASTIC PLATES MOMENT-MEMBRANE THEORY
Authors: Krylova E. Yu. , Sargsyan S. H.
Published: October 2024

Graphene being a two-dimensional nanomaterial created a new research area – its use as a functional element in various modern technology nanodevices. To open the way for such an application, it is necessary, first of all, to study the mechanical properties and its behavior under various conditions and learn how to manipulate them in a controlled way. All this necessitates an adequate graphene deformation simulations, the construction of an appropriate continuum theory that takes into account scale effects, microstructure and graphene crystal lattice physical parameters. This work aims at studying a rectangular graphene sheet in an electric field. For graphene deformations, the application of the transverse bending model of the elastic plates of the moment- membrane linear theory is justified. Forces of the electrical origin are modeled by means of a normal load applied to the front plate surface. A study was made of the influence of boundary conditions, the gap between the plate and the gate, the potential difference, and linear dimensions on the graphene sheet static transverse bending. The problem of graphene sheet natural vibrations is also solved. The graphene sheet vibration frequency lies in the GHz range. In the clamped boundary conditions case, the natural oscillations frequency is much higher than in the hinged supported case. Even at small deflections, a change in the constant voltage value has a significant effect on the graphene sheet natural frequency.
DISPERSION OF LONGITUDINAL WAVES PROPAGATING IN MATERIALS WITH POINT DEFECTS
Authors: Erofeev V. I. , Leonteva A. V. , Shekoyan A. V.
Published: October 2024

The paper investigates the propagation of harmonic waves in materials with point defects. The problem is described by a system of differential equations, which includes a dynamic equation of the theory of elasticity and kinetic equations of defect densities tak-ing into account the mutual influence of defects and a propagating wave, as well as mutu-al recombination of defects. We consider both limit cases, materials with one type of point defects (vacancies, interstitials), and the general case if the material contains both types of point defects (vacancies and interstitials). We analyzed the effect on the ampli-tude and velocity of the harmonic wave of the parameters of point defects characterizing the diffusion of defects, the rate of their recombination on drains and the change in the volume of the material when one point defect is formed in it. It has been shown that in media with vacancies, longitudinal waves of low frequency have a higher amplitude and velocity than in media with interstitials. At the same time, in media with vacancies, the velocities of low-frequency perturbations reach large values, and in media with intersti-tials they reach smaller values, compared to high-frequency perturbations. A frequency range has been identified in which the dispersion of longitudinal waves is significant, in media with vacancies it is normal, and in media with interstitials it is abnormal. The in-creasing diffusion coefficient or the decreasing dilation parameter contributes to a weak-er dispersion. It is noted that the diffusion coefficients of defects do not affect the exist-ence of an additional low-frequency wave. For high frequency waves, media with vacan-cies and interstitials are practically indistinguishable; the presence of any point defects almost does not affect the propagation rate of high-frequency perturbations and their amplitude.
CRYSTAL PLASTICITY FINITE-ELEMENT SIMULATIONS FOR QUASISTATIC DEFORMATION OF POLYCRYSTALS IN TERMS OF EXPLICIT DYNAMICS
Authors: Romanova V. A. , Balokhonov R .R. , Borodina A. , Shakhidzhanov V. S. , Lychagin D. V. , Emelianova E. S. , Pisarev M.
Published: October 2024

Crystal plasticity models combined with an explicit consideration of a polycrystalline structure are an effective tool for studying the deformation phenomena throughout length scales. A numerical solution to the boundary-value problems with an explicit account for misrostructural features requires extensive computational resources. The use of explicit time integration schemes effectively reduces computational costs yet providing a qua-sistatic solution with a high degree of accuracy. In this paper, we discuss the numerical aspects of crystal plasticity finite element simulations of quasistatic deformation phe-nomena in terms of explicit dynamics. The equations for plastic strain rate are formulated in a way to minimize strain rate sensitivity, which is the necessary condition for simulat-ing quasistatic deformation at artificially high strain rates. The problems of model verifi-cation and testing at the micro, meso, and macroscales are discussed using the example of aluminum single- and polycrystals.
METHOD FOR CALCULATING RESONANCES OF ACOUSTIC STRESSES AT THE BOUNDARIES OF AN ANISOTROPIC LAYER
Authors: Belyayev Y. N.
Published: October 2024

The conditions of occurrence of acoustic stress resonances at the boundaries of an anisotropic layer are investigated. In general, under the action of an incident elastic wave, six elastic waves are formed in an anisotropic layer. The total effect of these waves determines the stressstrain state of the layer and is displayed in the spectra of waves scattered by the layer into the environment. The scattering spectra and acoustic stresses were modeled by solving the equations of motion of a continuous medium and the generalized Hooke's law. This system of differential equations is solved with respect to the components of the displacement vector and the stress tensor in the Cartesian coordinate system. The Peano-Becker method of solving a system of differential equations by means of a matrix exponential is used. The components of the displacement vector and the stress tensor at two opposite boundaries of the layer with thickness d are expressed through each other using a sixth-order transfer matrix T = exp(Wd), where matrix W is determined by the parameters of the layer under study. The method of scaling and multiple squaring is used. According to this approach, T = (exp(Wd/m))m. A method for selecting the scaling parameter m is proposed to estimate the errors of truncation and rounding when calculating exp(Wd/m). A guaranteed accuracy and the best efficiency of calculations of all elements of the matrix exponential of the sixth order, in comparison with other known methods, is provided by the use of the method of polynomials of the principal minors of matrix W. The modeling of elastic wave scattering spectra (conversion coefficients) and stress dependences on the angles of incidence for cubic crystal layers is given using the example of indium. The interpretation of resonances of acoustic stresses arising in the crystal layer under the action of a shear wave incident on the crystal is given.
VARIATIONAL-DIFFERENCE SOLUTION OF DEFORMATION AND BUCKLING PROBLEMS OF ELASTOPLASTIC SHELLS OF REVOLUTION WITH ELASTIC FILLER UNDER COMBINED QUASI-STATIC AND DYNAMIC AXISYMMETRIC LOADINGS
Authors: Bazhenov V. G. , Kalinina Yu. A. , Nagornykh E. V. , Samsonova D. A.
Published: October 2024

The paper suggests a formulation and method for a numerical solution of deformation and buckling of elastoplastic shells of revolution with elastic filler under quasi-static and dynamic loadings. The problem is solved in a two-dimensional plane or generalized axisymmetric formulation with torsion. The governing system of equations is written in a Cartesian or cylindrical coordinate system. Modeling of deformation of an elastic-plastic shell is carried out based on the hypotheses of the theory of shells of the Timoshenko type, taking into account geometric nonlinearities. Kinematic relations are written in velocities and formulated in the metric of the current state. The elastoplastic properties of the shell are described by the flow theory with nonlinear isotropic hardening. Filler modeling is based on continuum mechanics hypotheses. The filler material is assumed to be linearly elastic. The variational equations of motion of structural elements (both shells and filler) are reduced from the three-dimensional equation of the balance of virtual powers of the work of continuum mechanics taking into account the accepted hypotheses of the theory of shells or a flat deformed state or generalized axisymmetric deformation with torsion. The modeling of the contact interaction between the shell and the filler is based on the condition of nonpenetration along the normal and slippage along the tangential. The finite-difference method and an explicit time integration scheme of the cross type are used to solve the defining system of equations. Approbation of the technique was carried out on the problem of buckling of a steel cylindrical shell with an elastic filler under quasi-static and dynamic compression by an external pressure that linearly increases with time. The results of the numerical study are compared with calculations performed using two other approaches developed earlier by the authors. The first approach is based on full-scale modeling of the process of deformation of the shell and filler within the framework of continuum mechanics. In the second approach, a simplified formulation is used, in which the deformation of the shell is modeled according to the hypotheses of the theory of non-sloping shells of the Timoshenko type taking into account geometric nonlinearities, and the filler is modeled according to the Winkler foundation hypothesis. The developed approaches make it possible to model the nonlinear subcritical deformation of shells of revolution with an elastic filler, to determine the ultimate (critical) loads in a wide range of loading rates taking into account geometric shape imperfections, to study buckling in axisymmetric and non-axisymmetric shapes under dynamic and quasi-static combined loadings in plane and axisymmetric deformations.
THERMOMECHANICAL COUPLED MODEL OF COATING SYNTHESIS ON A SUBSTRATE
Authors: Knyazeva A. G.
Published: October 2024

Among modern combined laser and electron-beam technologies, special attention is paid to those in which composition formation takes place directly in the process of product creation or coating synthesis. In the present work, a coupled model of coating synthesis on a substrate is constructed. When building the model, a sequential transition was carried out from a three-dimensional model of the coating synthesis process on the substrate to a one-dimensional model, which is useful for qualitative analysis. The one-dimensional model takes into account the main physical features of the physical and chemical processes during the synthesis, as well as the coupled nature of the heat transfer and deformation at the same time taking into account the differences in thermophysical and mechanical properties of different materials. When constructing the intermediate analytical solution, it is assumed that the system "substrate-coating" is in a plane stress state. As a result, explicit expressions for the components of stress and strain tensors connected with changes in temperature and composition are obtained. With the help of the obtained analytical solution, the thermokinetic part of the problem is modified and reduced to a more convenient form. Further, the experience accumulated in the field of macrokinetics is used, which allows us to model the processes of creating new materials (e.g., intermetallic or metal matrix composites) in modern technologies from the point of view of controlling the processes of phase formation in the reaction zone by a moving external source. The transition to dimensionless variables revealed complexes and parameters representing relations of characteristic scales of different processes. The parametric study of the model allowed us to establish interesting qualitative effects. It is demonstrated that the quasi-stationary regime is accompanied by physical and chemical processes in the region, which the laser beam had left, due to the heat accumulated in the materials. It is shown that the coupled nature of different processes significantly affects the dynamics of synthesis and the parameters of the quasi-stationary regime.
COMPUTATIONAL-EXPERIMENTAL METHOD FOR STRESS-STRAIN CURVE CONSTRUCTING UNDER CONDITIONS OF INHOMOGENEOUS STRESS FIELDS
Authors: Wildemann V. E , Mugatarov A. I , Khmelev A. A
Published: October 2024

In order to ensure reliability of structures, it is necessary to study equilibrium damage accumulation which initiates softening zones in solids. It is considered appropriate to use postcritical deformation models when conducting strength analysis of structures. However, obtaining complete stress-strain curves in standard tests is difficult due to the strain localization in the form of a neck. At the same time, the use of true stresses taking into account changes in a specimen cross section is incorrect due to the implementation of a complex stress state. In this regard, it is necessary to develop computational and experimental methods for constructing material stress-strain curves under conditions of inhomogeneous stress fields. In this case it seems reasonable to use data on strain fields on the body’s surface, which can be obtained, for example, using non-contact optical video systems. The paper presents the computational-experimental method for constructing a stress-strain curve under conditions of inhomogeneous stress fields. An elastoplastic model of an isotropic material is considered. The initial data of the method are two elastic constants, the yield stress value, the load diagram of a body with a stress concentrator, and the maximum values of strain intensity corresponding to various states. The developed method was tested by a numerical simulation of deforming an hourglass specimen and a plate with a stress concentrator. Stress-strain curves with and without a yield plateau are considered. The results demonstrate a high agreement between the initially specified and reconstructed stress-strain curves. A conclusion is made about the rationality of using the developed method when constructing stress-strain diagrams and necessity for its modernization to describe the postcritical deformation stage.
MODELING OF PHOTOPOLYMER CURING
Authors: Fedulov B. N
Published: October 2024

The paper considers the process of curing a photopolymer material. The effect of light on a photopolymer material triggers a reaction that leads to the conversion of polymer chains, which leads to the release of heat and an increase of temperature, solidification or an increase of stiffness of the material, and is also accompanied by a volumetric shrinkage. Such processes cause the distortion of the initial shape of the material. With nonuniform irradiation of the material, the processes are initiated with different intensities and a certain delay causing residual stresses. Stereolithography technology has become widespread in industry, in which the material is irradiated in certain areas, the so-called masks, after which the uncured material is removed. Modern photopolymer 3d printers are focused on this effect, which cures the material in layers with various masks. In 3D printing, the curing of the upper layer is accompanied by a higher shrinkage relative to the lower one, which by this time has a higher degree of curing leading to residual stresses. Thus, each new layer in a produced part initiates a gradual accumulation of residual stresses. As a result, there is a distortion of the originally planned shape of the product and a loss of strength characteristics. Residual stresses realized during the printing process can exceed the strength of the material, which often leads to a rapid increase in cracks and damage of the printed structure. This study proposes a model of a photopolymer material and an algorithm for modeling curing. It considers the process of stereolithography based on the action of a movable laser. A comparison with the experiment is given.
MATHEMATICAL MODELING OF THE DYNAMICS OF THE AEROELASTIC "PIPELINE – PRESSURE SENSOR" SYSTEM
Authors: Velmisov P. A , Tamarova Yu. A
Published: October 2024

This paper proposes mathematical models of mechanical systems "pipeline - pressure sensor" designed to control the pressure of the working medium in the combustion chambers of engines. In such systems, to mitigate the impact of vibration accelerations and high temperatures, the sensor is connected to the engine using a pipeline and is located at some distance from it. The movement of the working medium is described by linear models of fluid and gas mechanics. To describe the dynamics of an elastic sensitive element, linear models of the mechanics of a solid deformable body are used. Based on linear differential equations with partial derivatives, mathematical formulations of problems are proposed that correspond to three-dimensional models of pressure measurement systems in gas-liquid media for some pipeline cross-sectional shapes, namely, for a pipeline with a rectangular cross-section, with a section in the form of a sector and in the form of a ring. By introducing integral characteristics, the solution of problems is reduced to studying one-dimensional models. Equations have been obtained that make it possible to determine the pressure of the working medium in the combustion chamber at each moment of time by the value of deformation of the sensitive element of the sensor. Analytical and numerical-analytical methods for solving the corresponding initial-boundary value problems for systems of differential equations are proposed. In the analytical approach, the solution of the problem is reduced to solving a differential equation with a deviating argument. The numerical-analytical study of the problem is based on the application of the Galerkin method. Also, a numerical experiment was carried out and examples of calculating the deformation of the sensitive element of the sensor in the case of rigid fastening when specifying specific values of the mechanical parameters of the system are presented, also during setting the law of change in the excess pressure of the working medium in the engine.
Методи розрахунку теплових втрат і теплонадходжень в будівлях. Огляд, нормативні вимоги і практичні підходи в україні та світі
Authors: Кривошеєв М.О. , Грищенко Р.В. , Іващенко Н.В. , Самійленко С.М.
Published: October 2024

У роботі розглянуто методи розрахунків пікових та сезонних теплових навантажень і тепло-втрат, які є критично важливими етапами при створенні нових будівель, реконструкції існуючих та розробці систем тепло-, і холодопостачання. Ці розрахунки дозволяють інженерам-проєк­тувальникам, інвесторам, замовникам, постачальникам, монтажникам та іншим користувачам будівлі оптимізувати капітальні інвестиції, мінімізувати експлуатаційні витрати, зменшити CO2 слід будівлі, а також, використовуються як інструмент пошуку оптимальних проєктно-конструктивних рішень. Автори аналізують існуючі методи визначення тепловтрат і теплонадходжень, їх витоки, поширеність та основні відмінності. Продемонстровано переваги, можливі недоліки та потенційні напрямки розвитку з урахуванням українських реалій. На основі стандартів ДСТУ EN ISO 52016-1:2022 та ДСТУ CEN ISO/TR 52016-2:2022, що набули чинності у 2024 році, проводиться порівняння з попередніми нормативними документами, такими як ДСТУ Б EN ISO 13790:2011. Основна увага приділяється розрахункам пікових теплових навантажень, які визначають потужність джерел теплоти та холоду для будівель. Продемонстровано, що традиційні спрощені підходи, які використовуються в Україні, часто не враховують динамічні процеси теплообміну і призводять до похибок у розрахунках. У статті проаналізовано ASHRAE Heat Balance Method, який є найбільш точним, але й найскладнішим методом розрахунку теплових навантажень, а також методи, що базуються на теплових балансах та аналогії з електричними мережами, такі як погодинний метод EN ISO 52016-1. Відзначено, що європейські методи поступово гармонізуються з північноамериканськими, що відкриває нові перспективи для розвитку енергомоделювання в Україні, оскільки для практичного застосування ASHRAE Heat Balance Method необхідне спеціалізоване програмне забезпечення. Стаття підкреслює важливість використання точних методів розрахунків для забезпечення енергоефективності будівель і мінімізації їхнього впливу на довкілля. Приділено увагу практичним аспектам впровадження цих методів в Україні, потенційні переваги для інженерів, інвесторів та інших стейкхолдерів
Перспективи розвитку технологій накопичення низькопотенційного тепла газових (повітряних) потоків
Authors: Бошкова І.Л. , Альтман Е.І. , Мукмінов І.І. , Писаревський І.О.
Published: October 2024

Наведений аналітичний огляд наукових праць, присвячених дослідженню технологій накопичення енергії від низькопотенційних теплових потоків. Актуальність вивчення методів та методології акумулювання та утилізації теплоти газового (повітряного) середовища пов’язана з тим, що накопичення теплової енергії дає найкращу можливість збалансувати попит та пропозицію за рахунок подолання переривчастості і нестабільності реальних джерел тепла, що призводить до створення більш універсальної, стійкої та надійної системи теплопостачання або термостабілізації. Наголошується, що технології накопичення енергії (ТНЕ) набувають ключового значення у енергобалансі країни. Наведений аналіз акумуляторів теплоти за властивостями теплоакумулюючих матеріалів. Матеріал акумулятора ємкісного типу нагрівається (охолоджується) без зміни свого агрегатного стану, простота створення акумуляторів та теплоутилизаторів на їх основі дозволила на даний час розробити теплоакумулятори зі скельних порід, гравійно- водні схеми, запропонувати пісочні батареї для накопичення теплової енергії. Стверджується, що доцільність використання теплоутилізаторів з низькими температурними напорами може бути підвищена шляхом використання теплоносієм гранульованої насадки. Наведені загальні відомості щодо акумуляторів, які засновані на фазових переходах. Визначені експериментальні залежності для розрахунку коефіцієнту тепловіддачі в процесі перенесення тепла та маси при теплообміні в щільних шарах. Наведені математичні моделі процесів перенесення теплоти і маси в щільному шарі гранульованого матеріалу, які є найближчими до предмета дослідження. Аналізуються теплові процеси, що відбуваються під час проходження повітря крізь шар акумулятора. Аналізуються основні характеристики матеріалів та речовин для створення акумуляторів тепла
Gestión de los riesgos psicosociales. Factores de intervención
Authors: Pérez Vallejo Carlos
Published: October 2024

Los riesgos psicosociales y el estrés laboral forman parte de uno de los problemas en aumento y más complejos de salud, porque lo presentan un gran número de trabajadores y no se gestiona bien en las empresas. La evaluación psicosocial debe considerar los diversos factores o dimensiones identificados para un mejor análisis y comprensión de las causas de la exposición, por lo que así mismo requiere una propuesta de soluciones adaptada a la realidad observada que integre los factores que están interrelacionados. Así, se debe proponer acciones preventivas que permitan actuar sobre varios factores al mismo tiempo, lo que resulta muy útil para establecer prioridades. Se presentan en este articulo diversas metodologías de evaluación para la gestión de los riesgos psicosociales y sus factores para la intervención. Además, basándose en el estudio de calidad de vida laboral realizado por el autor (Pérez, 2020), en el que se utilizaban algunas de las metodologías presentadas, observa el nivel de correlación entre los aspectos de la calidad de vida en el trabajo como el clima organizacional, el burnout, el engagement, los factores psicosociales y la percepción del estado de salud de los trabajadores.
Entre el encanto y la bioseguridad: riesgos biológicos para profesionales de salones de belleza en la localidad de Bosa
Authors: Cortés Hernández Angie Daniela , Reyes Rodríguez Julio Alejandro , Garzón Tovar Ligia Nathalya , Corredor Puentes Sindy Paola , Torres Wilmar Ariza
Published: October 2024

Esta investigación en curso aborda una problemática a los riesgos biológicos presentes en las salas de belleza y estética en la localidad de Bosa de la ciudad de Bogotá, Colombia, en donde se pretende identificar cómo estos afectan la salud de los profesionales que trabajan en el sector. Con esta investigación se pretende generar un plan de recomendaciones enfocado en la prevención de enfermedades asociadas al riesgo biológico y los tipos de agentes contaminantes a los que se exponen. Lo anterior a partir de una metodología mixta que permite la revisión y análisis de bibliografía relacionada y ejercicios de observación y   aplicación de herramientas para el levantamiento de datos sobre bioseguridad, es importante la identificación de fuentes generadoras de riesgo biológico y el trazado de protocolos de bioseguridad y recomendaciones.
La fundamentación teórica recopila estudios previos sobre riesgos laborales en peluquerías y lugares de estética, resaltando la importancia de la bioseguridad y el control de riesgos. Se mencionan medidas preventivas como el recambio de instrumental, uso de productos autorizados, uso de uniformes y protección adecuada, y eliminación segura de material desechable.
Trabajo Migrante Clandestino: Un desafío para los SG-SST y su responsabilidad ética
Authors: Orellanos Chaparro Edgar Stefan , Quiroz Rubiano Mónica María
Published: October 2024

A través de un relato sencillo y escalonado, se presenta al lector un dilema dentro de los estudios migratorios, esto es, el relativo a los retos que enfrenta el líder para la gestión de la seguridad y salud en el trabajo en torno a los trabajadores migrantes en condición clandestina. Para ello se evaluará desde el ideal convencional regulatorio frente al trabajo migrante, hasta el nivel de cumplimiento de los Estados en torno a esas disposiciones, para enfrentarlo a la responsabilidad derivada del ser y quehacer del profesional en GSST como garante del buen vivir de los trabajadores y promotor de las condiciones de dignidad laboral.
 El presente artículo, se presenta como el primero de una serie de artículos derivados de una investigación centrada en la protección, estudio y atención de la migración clandestina en los diferentes pilares de responsabilidad objetiva y universal de los Estados, por lo que se espera que su lectura y comprensión sirva de apoyo para la atención de esta categoría de migrantes en una de las esferas más importantes del ser humano, el trabajo.