bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determining the stressed-strained state of concrete in the zone of exposure to local laser radiation
Authors: Karkhut Ihor 
Published: July 2021

This paper reports the results of the physical and numerical experiments on determining the stressed-strained state of concrete in protective structures in the region of the effect of local point laser radiation. The software package LIRA10.8 (release 3.4) was used to build a computer model in the statement of a stationary thermal conductivity problem. To this end, the findings from the experimental studies were applied – the resulting temperature distribution and changes in the structure of concrete on the surface and deep into concrete cubes for more than 120 samples of concrete with three levels of moisture content: dried, natural humidity, and water-saturated. This paper gives the parameters of the simulation, the results of a numerical experiment, their analysis, and comparison with the results of a physical experiment.
The temperature fields when establishing the dynamic temperature equilibrium, the level of stresses in concrete, derived from the physical experiments, correlate well with the results of the numerical experiment. The maximum temperature determined by the optical method at the surface of concrete was 1,350+50 °С. Deviations at control points do not exceed 12–70 °С in the temperature effect zone and 18–176 °С (1–11 %). At the rated radiation power of 30 W, the second stage of interaction was achieved; at 100 W – the fourth stage for concrete with a moisture content of 0–2.5 %; and, for water-saturated concrete, the fifth stage of interaction with the laser beam. A significant decrease in the thresholds between the stages of interaction between laser radiation and concrete was revealed, especially water-saturated concrete, compared to the thresholds for metals (the thresholds between the third and fifth stages were reduced by 103–104 times). The destruction of the walls of water-saturated pores in concrete occurred under the pressure of water vapor. The tangent stresses, in this case, were 1.7 MPa, and the values for the coefficient Kр, determined by the method of acoustic emission, were in the range of 4‒6. Such results explain the absence of normal microcracks due to the hoop effect.
It was established that in the contact zone between a laser beam and concrete, about 90 % of the radiation energy dissipates, and in the adjacent heating zone ‒ up to 77 %. The optimal speed of beam movement when cleaning the concrete surface from organic, paint, and other types of contamination of 0.5–2 mm/s (surface temperature, 100–300 °С) has been proposed
Comparing the effect of nanoclays on the water-resistance of intumescent fire-retardant coatings
Authors: Vakhitova Liubov , Kalafat Kostyantyn , Plavan Viktoriia , Bessarabov Volodymyr , Тaran Nadezhda , Zagoriy Glib 
Published: July 2021

This paper reports a study into the effect of nanoclays on the water-resistance of the intumescent system ammonium polyphosphate/melamine/pentaerythritol/titanium dioxide/polymer (ethylene vinyl acetate (EVA) or styrene acrylate (SA).
It has been established that adding nanoclay to a coating based on ethylene vinyl acetate increases the fire resistance limit of a metal plate by 30 %, and to a coating based on styrene acrylate – by 50 %. At the same time, coatings that include the EVA polymer are characterized by greater fire-retardant efficiency and less water resistance than coatings containing the SA polymer.
It has been shown that intumescent coatings, regardless of the nature of the polymer, under the conditions of 80 % humidity over 800 days their reduce fire-protective properties by an average of 10 %. The loss of coating fire resistance occurs due to the leaching of pentaerythritol, ammonium polyphosphate, and polymer degradation by hydrolysis. The admixtures of nanoclays with a high degree of exfoliation to the studied system create a barrier effect and maximize the chemical formulation of the intumescent coating. The fireproof properties of coatings with organically-modified montmorillonite admixtures are maintained or reduced to 5 % under the conditions of 80 % humidity over 800 days.
It has been determined that the direct effect of water on the coating over a period of more than 2 days leads to a significant decrease in the swelling coefficient of intumescent coatings, regardless of the content of a nanoclay admixture in their composition. At the same time, the half-decay period of coatings without nanoclay, calculated on the basis of solubility constant in water, is 0.5 days. For coatings, which include the admixtures of organically-modified nanoclays, the half-decay period increases to 2 days.
The results reported in this paper could be recommended for designing water-proof fire-resistant reactive-type nano-coatings with prolonged service life.
Influence of the structure and thermomechanical properties of oriented carbon plastics on their tribotechnical characteristics
Authors: Dykha Aleksandr , Drobot Olga , Oleksandrenko Viktor , Pidhaichuk Svitlana , Yaroshenko Pavlo , Babak Oleg 
Published: July 2021

It has been established that carbon plastics are increasingly used in various industries as structural materials. By the set of their properties, carbon plastics outperform steel, cast iron, alloys of non-ferrous metals. However, the application of these materials for parts of machine friction units is still limited due to the difficult operating conditions of modern tribosystems. This work aims to conduct a comprehensive experimental study of the tribological properties of materials in the tribosystem "carbon plastic-metal" taking into consideration their structure, as well as the mechanical-thermal characteristics. Comparative tests of the dependence of the friction coefficient on load for metal and polymeric anti-friction materials have shown a decrease in the friction coefficient for plastics by 3...4 times (textolite, carbotextolite, and carbon-fiber plastics). The influence of the filler orientation relative to the slip plane on the anti-friction properties of carbon-fiber plastics was investigated; it was found that the direction of fiber reinforcement in parallel to the friction area ensures less carbon-fiber plastic wear. A linear dependence of the wear intensity of carbon-fiber plastics, reinforced with graphite fibers, on the heat capacity and energy intensity of the mated steel surface has been established. Based on the microstructural analysis, a layered mechanism of the surface destruction of carbon-fiber plastics was established caused by the rupture of bonds between the fiber parts, taking into consideration the direction of the fibers' location to the friction surface. The results reported here could provide practical recommendations in order to select the composition and structure of materials for the tribosystem "carbon-fiber plastic-metal" to be used in machine friction units based on the criterion of improved wear resistance
Development of a method for selecting a cruising mode and engine control program of a ramjet aircraft
Authors: Kislov Oleh , Shevchenko Mykhailo 
Published: July 2021

For supersonic cruising, combined power plants can be used, in which a gas turbine engine reaches the cruising mode, and a ramjet is used for cruising. Supersonic transoceanic flights are characterized by a long cruising segment, which is decisive in terms of required fuel mass. Therefore, the selection of cruising and engine operation parameters is an important task. As a rule, when selecting the cruising mode, the range parameter is used, which depends on the flight and engine operation modes. To take into account the influence of the ramjet operating mode on the range parameter, dimensionless relationships of engine parameters with control factors were obtained. Using the obtained relationships together with the equations of aircraft motion in steady horizontal flight, it is shown that the values of the engine control factors and the range parameter do not change at the altitudes of 11...20 km. This made it possible to conclude that the range parameter can be increased only by selecting the cruising and engine parameters that provide the minimum specific fuel consumption. The variable cruising parameters are speed and initial altitude. A method for selecting the cruising and ramjet operation parameters was developed, based on the analysis of the relationship between the range parameter and the flight speed and initial altitude at the most advantageous values of the engine control factors. The obtained relationships allow selecting the cruising parameters and the engine operating mode, taking into account the restrictions. It is shown that the specific fuel consumption decreases by 0...30 %, depending on the engine operating mode, when the control program is optimized
Multicriteria optimization in the problem of computer-aided design of hybrid solar energy systems
Authors: Sineglazov Victor , Karabetsky Denis , Chumachenko Olena 
Published: July 2021

This paper reports an approach to optimizing the structure of a hybrid solar energy system (HSES), used in the task of automated design, under two modes: independent and connected to the network. The proposed HSES includes a solar energy system (SES), an energy storage system (ESS) powered by rechargeable batteries (RBs), a set of diesel generators (DGs), and a network-connecting system. This paper has identified models of the HSES elements' power and proposed a control algorithm based on rules that assess the state of the system during operation.
The energy models in conjunction with the control algorithm make it possible to model the system's operation stage over a predefined time interval. The proposed approach is based on solving a multicriteria optimization problem (MCO). MCO takes into consideration the minimization of system costs and the total cost of the system, minimizing fuel use, maximizing reliability, and minimizing the use of non-renewable energy sources. A solution to the MCO problem is based on using a Pareto-optimal solution search algorithm, underlying which is the NSGA-II genetic algorithm employing the proposed set of crossbreeding, mutation, and breeding operators. The devised procedure makes it possible to determine the structure of HSES, which includes a set of the number of solar panels, RBs, and DGs. The result is three variants of HSES for a household for two people (Kyiv, Ukraine), under an autonomous mode and in the regime connected to the electricity grid. Given the possibility of selling electricity at a green tariff during the year, the reported solution makes it possible to reduce the estimated cost of the system by up to 45 %. The use of simulation has helped conduct a detailed analysis of the system's performance throughout the year
Heat transfer intensity at water boiling on the surface of a capillary structure under sub-atmospheric pressure
Authors: Melnyk Roman , Kravets Vladimir , Lipnitskyi Leonid , Danylovych Andrii 
Published: July 2021

This paper considers the effect of structural parameters and saturation pressure on the intensity of heat transfer from boiling on porous structures made of copper metal fibers. The study involved changing the structural and geometric characteristics of porous samples and saturation pressure. The study regime parameters were chosen based on the conditions of operation of steam chambers, namely the horizontal orientation of the work area, the capillary transport of the heat carrier to the work area.
It was determined that reducing saturation pressure from 0.1 MPa to 0.012 MPa leads to a reduction in heat transfer by 15‒20 % depending on the parameters of porous structures. This pattern has been explained in this paper by the increased detachable diameters of steam bubbles that thus overlap part of the capillary structure's vaporization area, which leads to a decrease in the values of the discharged heat flux at the same temperature gradient values.
The influence of values of the porosity and diameters of fibers, which the samples of a capillary structure were made from, was ambiguous. The parameter chosen for generalizing the data obtained was an effective diameter of the samples' pores, which is a more general characteristic.
The generalization of the experimental data has demonstrated that the efficiency of heat transfer increases with an increase in the effective diameter of pores in the examined range from 20 to 90 µm. Estimation dependences have been built to determine the intensity of heat transfer under sub-atmospheric pressures for metal-fibrous porous structures at a deviation of up to ±30 %.
It turned out that the resulting dependences could be used to determine the intensity of heat transfer by the examined powder structures under the sub-atmospheric pressure conditions. Applying these dependences would make it easier to design thermal stabilization systems based on steam chambers.
Ensuring adhesion between the asphalt-concrete road surface and rigid base at the roadbed design stage
Authors: Dorozhko Yevhen , Batrakova Angelika , Tymoshevskyi Vladislav , Zakharova Elina 
Published: July 2021

Arranging asphalt-concrete layers on a rigid base in the form of cement-concrete slabs can significantly improve the transporting and operational performance of the road surface. Such a structural solution is appropriate in almost all countries of the world since cement-concrete slabs retain high strength for a long time. To prevent the rapid destruction of an asphalt-concrete road surface on a rigid base, it is necessary to ensure reliable adhesion between the layers' contacts and, at the design stage, to test the adhesion strength by estimation.
This paper has substantiated a criterion of adhesion strength in the contact between an asphalt-concrete road surface and the rigid base. The calculation involves comparing the active tangent stresses in the contact between layers dependent on the effect of the vertical and horizontal components of the transport load with the magnitude of permissible tangent shear stresses in the contact of layers.
The parameters for an estimation model have been established; the stressed-strained state of the roadbed structure has been simulated using a finite element method. When modeling the stressed-strained state and calculating based on the strength criterion, different vehicle traffic conditions have been considered, as well as the effect of temperature on the strength parameters of the asphalt-concrete layer and the tar layer. The conditions for vehicle movement, taken into consideration when designing, correspond to the conditions of movement along the road, along the curves in the plan and profiles, and notion conditions at car emergency braking. Practical recommendations have been compiled for assigning the minimum permissible thickness of an asphalt-concrete layer on a rigid base, which must be followed at the design stage due to the condition for ensuring reliable adhesion between the layers' contacts. The minimum permissible thickness ranges from 2 cm to 10 cm, depending on the conditions of movement, temperature, and the type of tar.
QSAR analysis and molecular docking study of pyrrolo- and pyridoquinolinecarboxamides with diuretic activity
Authors: Golik Mykola , Titko Tetiana , Shaposhnyk Angelina , Suleiman Marharyta , Drapak Iryna , Sych Irina , Perekhoda Lina 
Published: July 2021

The aim. The aim of the study was to reveal QSAR and ascertain the possible mechanism of action via docking study in the row of tricyclic quinoline derivatives with diuretic activity.
Materials and methods. Pyrrolo- and pyridoquinolinecarboxamides with proven diuretic activity were involved in the study. Molecular descriptors were calculated using HyperChem and GRAGON software, and QSAR models were built using BuildQSAR software. For receptor-oriented flexible docking, the Autodock 4.2 software package was used.
Results. Multivariate linear QSAR models were built on two datasets of quinolinecarboxamides: Vol = a∙X1 + b∙X2 + c∙X3 + d, where Vol – volume of the daily produced urine in rats, Xi – molecular descriptor. QSAR analysis showed that the diuretic activity is determined by the geometric and spatial structure of molecules, logP, the energy values, RDF- and 3D-MoRSE-descriptors. Based upon internal and external validation of the models, the most informative two-parameter linear QSAR model 3а was proposed. Docking data showed the high affinity of two lead compounds to the carbonic anhydrase II.
Conclusions. QSAR analysis of tricyclic quinoline derivatives revealed that the diuretic activity increases with the increase of value of logP, refractivity, and dipole moment and with the decrease of volume, surface area, and polarization of the molecules. Increase of values of such energy descriptors as bonds energy, core-core interaction, and energy of the highest occupied molecular orbital results in higher diuresis; decrease in hydration energy leads to higher diuretic activity. Based upon molecular docking calculation, the mechanism of diuretic action is proposed to be carbonic anhydrase inhibition.
QSAR models and docking data are useful for in-depth study of diuretic activity of tricyclic quinolines and could be a theoretical basis for de novo-design of new diuretics
Analysis of literature data on the relationship between vitamin D deficiency and type 1 diabetes mellitus
Authors: Fylymonenko Victoriia , Galuzinska Liubov , Briukhanova Tetiana , Chumak Olena , Yatsenko Olena 
Published: July 2021

Type 1 diabetes mellitus is a chronic autoimmune disease in which genetic predisposition and environmental factors play a major role. Vitamin D deficiency is becoming a pandemic in the world and is observed in type 1 diabetes mellitus.
The aim. Analytical review of available literature data on the relationship of vitamin D deficiency with the development and course of type 1 diabetes mellitus.
Materials and methods. Analysis of open sources of scientific literature.
Results and discussion. Clinical observations and experimental studies show that vitamin D deficiency is one of the risk factors for the development of type 1 diabetes, and is a consequence of this disease. The status of vitamin D in the body is determined not only by the intake of vitamin from the outside, but also by the activity of tissue transport and metabolism systems, which have a high degree of polymorphism. Numerous studies show the positive effect of the use of vitamin D preparations in the prevention and treatment of type 1 diabetes mellitus. However, there are works in which there is no protective effect.
Conclusions. Thus, the optimization of the status of vitamin D in the body is a promising measure to prevent the development of type 1 diabetes and facilitate its course, but requires further research.
Factores asociados con síndrome metabólico y calidad de vida de adultos en un municipio noreste de brasileño
Authors: Santos Isleide Santana Cardoso , Boery Rita Narriman Silva de Oliveira , Fernandes Josicélia Dumêt , Rosa Randson Souza , Ribeiro Ícaro José dos Santos , Souza Andréa dos Santos 
Published: July 2021

Introducción: El Síndrome Metabólico (SM) se considera actualmente una enfermedad multifactorial relacionada con la inflamación asintomática, insidiosa y deletérea que predispone al individuo a la vulnerabilidad al agregar marcadores de riesgo cardiovascular. Objetivo: analizar los factores asociados al síndrome metabólico y calidad de vida en adultos usuarios de una unidad de salud. Materiales y Métodos: estudio transversal realizado con 108 usuarios adultos. La recogida de datos se realizó mediante un cuestionario sociodemográfico, clínico y metabólico, estructurado y mediante el cuestionario The Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36). Para el diagnóstico de Síndrome Metabólico se utilizaron los siguientes criterios: aumento de la circunferencia abdominal e hipertensión arterial, diabetes, hipertrigliceridemia y colesterol HDL bajo. El análisis estadístico se realizó utilizando el software Statistical Package for Social Sciences (SPSS) 21.0. Resultados: Se identificó síndrome metabólico en el 88,0% de los adultos. De este total de usuarios evaluados con el síndrome, el 87,4% de los individuos eran mujeres; 71,7% con diabetes; 87,0% tenía hipertensión arterial; Se identificó sedentarismo en 53,7%. En la valoración del IMC, predominaron el sobrepeso y la obesidad en 68,4% y 24,9%, respectivamente. Los dominios con las puntuaciones más bajas de calidad de vida fueron Salud general y Vitalidad. Conclusiones: el estudio permitió identificar el Síndrome Metabólico en la mayoría de los adultos evaluados. Hubo una baja percepción de la calidad de vida entre los adultos en todos los dominios, excepto en los aspectos físicos y vitalidad. Por tanto, es necesaria la vigilancia y educación sanitaria de la población estudiada y la mejora de su calidad de vida.
Como citar este artículo: Santos, Isleide Santana Cardoso; Boery, Rita Narriman Silva de Oliveira; Fernandes, Josicélia Dumêt; Rosa, Randson Souza; Ribeiro, Ícaro José dos Santos; Souza, Andréa dos Santos. Factors associated with metabolic syndrome and quality of life of adults in a northeast brazilian municipality. Revista Cuidarte. 2021;12(2):e.1678 http://dx.doi.org/10.15649/cuidarte1678
Le genre et ses indices: les normes internationales sur l’égalité femmes / hommes en question
Authors: Le Guen Mireille , Schantz Clémence , Pannetier Julie , Etesse Manuel 
Published: July 2021

Dans les années 1990-2000, la communauté internationale s’est engagée pour la lutte contre les inégalités entre les femmes et les hommes. Les institutions se sont alors dotées d’outils permettant de mesurer les évolutions dans ce domaine à l’échelle internationale. Divers « indices d’inégalité de genre » ont été élaborés. S’ils ont subi des critiques méthodologiques menant à des réajustements, les cadres conceptuels utilisés n’ont en revanche jamais été analysés à l’aune des savoirs sur le genre. Notre analyse porte sur les indices du FEM, de l’OCDE et du PNUD et révèle que ces indices reposent sur des postulats qui participent d’une vision située et réductrice des rapports sociaux de sexe. Par ailleurs, les domaines dans lesquels sont mesurées les inégalités de genre tendent à réifier les rôles sociaux traditionnels attribués aux femmes et des hommes. Enfin, ces indices, parce qu’ils sont le résultat d’une approche située, mettent en avant certaines formes d’inégalités de genre et en oublient d’autres, ce qui limite largement leur utilisation dans un cadre comparatiste et scientifique.
Infécondité, procréation médicale et inégalités sociales
Authors: Bonnet Doris , Duchesne Véronique 
Published: July 2021

Le développement des technologies de la reproduction, et notamment de la fécondation in vitro (FIV), permet aujourd’hui à certains couples (hétérosexuels) infertiles africains d’avoir un enfant. L’offre d’assistance médicale à la procréation (AMP) s’inscrit dans un système de soins libéral qui s’adresse prioritairement aux classes moyennes et urbaines. Certains couples ne trouvent pas dans leur pays les conditions ou les techniques recherchées et sont amenés à se déplacer à leurs frais dans des pays limitrophes ou encore en Europe ou aux États-Unis. D’autres couples résident en France où l’AMP est encadrée par les lois de bioéthique. Ce chapitre montre comment l’espace mondialisé de la reproduction renvoie à un rapport inégalitaire aux biotechnologies de la reproduction des couples africains infertiles selon leurs conditions socio-économiques, mais aussi selon leur lieu de résidence. Ce contexte renvoie au cadre théorique de la « reproduction stratifiée ».