bluuebunny/crossref_metadata_2025 huggingface dataset:
Tasa de fecundidad infantil y la paulatina no declaración de los progenitores en Costa Rica (2000-2019)
Authors: Fuentes Rodríguez Eugenio
Published: July 2021

Introducción: la maternidad infantil debe evidenciarse por su propia naturalización social como producto de violaciones. Es relevante su estudio luego de aprobadas algunas leyes que buscan evitarla. Objetivo: analizar el comportamiento de la tasa de fecundidad en niñas entre 10 y 14 años en Costa Rica (2000-2019) y la edad de los perpetradores o «padres» en el marco de los aparatos ideológicos de Estado, desigualdad social y dentro de un contexto social conservador. Método: la información se extrajo de las bases de datos en línea del Instituto Nacional de Estadística y Censos. El abordaje es cuantitativo, con un estudio correlacional y no experimental de la población descrita en  todo el país y en áreas geográficas pequeñas. Resultados: la fecundidad infantil ha disminuido entre los años 2000 y 2019. La edad estimada de embarazo es cuando se cumplen los 13 años. Se detectaron áreas geográficas con mayores niveles de fecundidad dentro y fuera del Gran Área Metropolitana. Se evidenció estadísticamente que algunas leyes han contribuido al aumento considerable de perpetradores no declarados luego de 2016. Todo esto fue validado por instituciones religiosas y los medios de comunicación lo pregonaron como positivo, a pesar de la jurisprudencia nacional e internacional. Conclusiones: esta información es trascendental para orientar las políticas públicas educativas y de salud desde el primer nivel de atención, con miras a promover los derechos reproductivos de las niñas.
Interrelaciones entre el sentido de la vida, la actividad física, la red de apoyo social, la edad y el género en adultos mayores
Authors: Rodríguez-Méndez Diego , Solano-Mora Luis , Corrales-Araya María Antonieta , Murillo-Campos Edgar , Cortés-Gómez Brynel
Published: July 2021

Introducción: los adultos mayores que asisten a los centros diurnos tienen la oportunidad de interactuar con sus pares y realizar actividades, lo cual podría incidir en su sentido de la vida. Objetivo: evidenciar las asociaciones entre el sentido de la vida, la actividad física, la red de apoyo social, la edad y el género en siete centros diurnos de la provincia de Heredia, Costa Rica. Metodología: el estudio es cuantitativo de corte transversal. Se eligieron siete centros diurnos de los cuales se seleccionó una muestra por conveniencia de 77 adultos mayores. Las variables investigadas fueron el sentido de la vida, la actividad física, la red de apoyo social, la edad y el género. Para la recolección de datos se utilizaron autoreportes y los investigadores ayudaron a aclarar dudas sobre las preguntas. Resultados: el 46 % de las personas mayores reportó una falta de sentido de la vida y un 36 % un nivel de actividad física baja. Se determinó una asociación significativa entre la red de apoyo social y el sentido de la vida (b = .911; p < .001), entre la edad y la red de apoyo social (b=.30 p=.048), y entre el apoyo social y el género femenino (b=-6.08, p=.010). Conclusiones: la red de apoyo social es un predictor del sentido de la vida, así como la edad y el género predicen la red de apoyo social; pero no la actividad física reportada sobre las variables investigadas.
Energy, Climate Changes, COVID-19: Romanian answers
Authors: Danubianu Mirela , Teodorescu Cristian
Published: July 2021

The EU's energy and climate change concerns have materialized in the last years in launching 2020-2030 strategic initiatives. The Plan Up project seeks to monitor this area. Each EU member must implement its own plan (NECP) structured on 5 main dimensions: energy security, decarbonization, energy efficiency, internal energy market, research-innovation-competitiveness. Romania is committed to reducing CO2 emissions by over 43%, to increasing energy efficiency by over 37% and to promote renewable energy to reach approx. 28% of the portfolio (97% for the rail transport sector). The impact of COVID-19 must be immediately included in the NECP and seen as an opportunity and the NECP, adapted accordingly. The paper presents this Project and the potential Romanian contribution in the Transport Sector, a sector currently in a massive reorientation (electric cars, encouraging public transport, anti-Diesel offensive, etc.) and the most severely affected by COVID-19. The vast Romanian experience in the use of dimethyl-ether (DME) as an ecological substitute for diesel is presented, which would dramatically reduce the need for investments in the conversion of the current fleet of diesel vehicles. DME is also as a C3-C4 fraction substitute (CFC), in sprays, refrigerant agent in refrigerators, etc. Examples of applications of the proposed solution are given (USA, Scandinavia). The advantages of DME would be that it can be synthesized from renewable sources (municipal, agricultural waste), thus adding value to waste and improving the energy resources balance of Romania and the EU. The paper also seeks an objective critique of the (not so-)miracle solution of electromobility.
Mongolian place names in Fernão Mendes Pinto’s Peregrinação
Authors: Canosa Afonso Xavier , Brosig Benjamin
Published: July 2021

The Mongolic term khaan (‘king’), for which there is full correspondence, semantic and phonological, in sixteenth century Portuguese cão, is used as a starting-point to identify the graphemes that correspond to several Mongolic consonants in place names transcribed in the chapters related to the Tartars in Fernão Mendes Pinto’s Peregrinação (1614). With the deduced rules of pronunciation at hand, it is possible to establish new pairs of lexical correspondences and solve a brief lexicon extracted from the list of Tartar toponyms.
The Scripture of Filial Piety [Revealed] by Wenchang: A Bibliographical Study
Authors: Jiechen Hu
Published: July 2021

This article discusses the date of the Scripture of Filial Piety [Revealed] by Wenchang (Wenchang xiaojing 文 昌孝經). The central claim of this contribution is that the Scripture appeared during the Ming-Qing transition, being a product of the ritualisation of the Classic of Filial Piety (Xiaojing 孝經). By examining more than twenty diﬀerent editions, this article identiﬁes at least three diﬀerent lines of textual transmission, each connected to distinctive commentaries and reprints. Confucian literati were the main social actors responsible for the creation, reproduction, redaction, and annotation of the extant editions.
Sagang Sechen’s Teachings Reconsidered
Authors: Kara György
Published: July 2021

This is a revision of J.R. Krueger’s reading and translation of the Ordos Prince Sagang Sechen’s moralistic poem written in 1662 in seventy-nine alliterative quatrains attached to his Erdeni-yin tobči, the Jewel Summary, the ‘classical’ chronicle of pre-modern Mongol historiography. A new reading and interpretation is oﬀered with ample commentary.
Harmonic Uniformity and Hungarian front/back harmony
Authors: Rebrus Péter , Törkenczy Miklós
Published: July 2021

In the paper we argue against the traditional assumption about the relationship between morphology and harmony in Hungarian according to which monomorphemic and polymorphemic (suffixed) forms behave in the same way harmonically within the domain of harmony. We show that the harmonic properties of the root are inherited by morphologically complex forms based on the root and this can override the phonological restrictions on harmony. We propose an Optimality Theory analysis of the interaction between the phonological constraints on harmony and the paradigm uniformity constraint Harmonic Uniformity.
Underlying representation of [w]-final words in Brazilian Portuguese: Evidence from morphological derivation
Authors: Schwindt Luiz Carlos
Published: July 2021

This paper deals with the underlying representation of [w]-final words in Brazilian Portuguese, usually spelled with  and pronounced as [w] and occasionally as [ɫ] (e.g.,papel/ [paˈpɛw] ~ [paˈpɛɫ] ‘paper’). It focuses on non-verbs derived by a vowel-initial suffix preceded by [l] (e.g.,papel+eiro‘paper+suffix’ / [papeˈlejɾʊ] ‘papermaker’;cliente+ismo‘client+suffix’ / [kliẽnteˈlizmʊ] ‘patronage’). The results from a pseudoword task answered by 219 participants contrasted to lexicon data from Corpus Brasileiro show that native speakers associate such derived forms with bases already containing [l] in the last syllable, either in the onset or the coda position. This observation is interpreted in a constraint-based approach, with the assumption that a demand for alignment between vowel-initial suffixes and roots closed by /l/, along with the requirement for phonological correspondence between base and derivative, is highly ranked in a grammar that accounts for learning morphophonological representations in the language.
Seleka’s profane potency
Authors: Tecun Arcia , Petelo Taniela
Published: July 2021

The Seleka art and kava collective is found in the heart of the Kingdom of Tonga’s urban centre and capital. Seleka is a transformed nickname which is a play on the word kasele, meaning toilet or outhouse, an external othering and internal acceptance of divergence within Tongan society. Seleka is a site where urban Tongans paint and drink kava together while listening to rebellious music, incorporating some of the aesthetics and politics of these musical genres into their group. They have a broader musical playlist than most kava clubs in Tonga, which includes punk, rock and metal. This article explores the character of Seleka as a radical critique to Western introduced social constructs such as puritan respectability, which have become part of Tonga’s modern cultural norms. Seleka performs and generates mana (potency/prestige) through noa (profanity/neutralization) by desecrating the ‘sacred’ and recreating a new alternative. This act of rebellion is presented as a contemporary manifestation of an ancient Tongan practice where the ‘profane’ was used to identify and bring balance to the most tapu (‘sacred’/protected).
Interview: Pasifika climate activist music in New Zealand, queered and disabled
Authors: Zemke Kirsten , Leleiga Lim-Cowley Luka
Published: July 2021

This discussion is between Dr Kirsten Zemke, from the University of Auckland and her MA student-poet, dancer and climate activist, Luka Leleiga Lim-Cowley. Luka’s musical performance experiences in, and insights from, Pasifika climate activist and Pacific Indigenous sovereignty events led them to further explore the perspectives of Pasifika queer and/or disabled activists. Luka argues that disabled and gendersexuality-divergent folks should be at the foreground of these movements, as they are the most threatening to white supremacy—the ultimate culprit in Indigenous displacement and climate change. Luka’s poem, ‘Water (remix ii)’, is presented in full; the discussion flows through topics such as gender, religion, Indigeneity, and the continuums of time and space.
Effect of High-Flux versus Low-Flux Dialysis on the Rate of Bacteremia in Hemodialysis Patients
Authors: Dahouk Ali , Sinno Loubna , Rabah Housam
Published: July 2021

Bacteremia in dialysis patients is a major risk factor of mortality. The aim of this study was to assess the effectiveness of dialysis with high-flux versus low-flux dialyzer regarding risk of bacteremia in dialysis patients. This was a retrospective cohort study that included dialysis patients who underwent dialysis therapy at old dialysis center where old low-flux dialyzers were used and the new dialysis center where high-flux dialyzers were used. The rate of positive culture was more in high-flux group (37.0%) compared to low-flux group (24.5%), although the difference was not statistically significant (P = 0.13). The vascular access was mostly permanent catheter in high-flux group compared to low-flux group (48.9% vs. 28.6%, respectively; P = 0.06), while arteriovenous (AV) fistula was more prominent in low-flux group compared to high-flux group (65.3% vs. 47.8%, respectively; P = 0.06). This was reflected in the type of bacteria, which was mostly from Gram-positive family (Staphylococcus). The results showed higher risk of bacteremia in high-flux group as compared to low-flux group; however, permanent catheters were more prominent in high-flux group.
Broken rotor bars fault detection in induction motors based on current envelope and neural network
Authors: Mustafa Mohammed Obaid
Published: July 2021

The growing demand for dependable manufacturing techniques has sped up research into condition monitoring and fault diagnosis of critical motor parts. On the other hand, in modern industry, machine maintenance is becoming increasingly necessary. An insufficient maintenance strategy can result in unnecessarily high downtime or accidental machine failure, resulting in significant financial and even human life losses. Downtime and repair costs rise as a result of failure. Furthermore, developing an online condition monitoring method may be one solution to come up for the problem. Early detection of faults is very vital since they grow quickly and can cause further problems to the motor. This paper proposes an effective strategy for the classification of broken rotor bars (BRBs) for induction motors (IMs) that uses a new approach based on Artificial Neural Network (ANN) and stator current envelope. The stator current envelope is extracted using the cubic spline interpolation process. This is based on the idea that the amplitude-modulated motor current signal can be revealed using the motor current envelope. The stator current envelope is used to select seven features, which will be used as input for the neural network. Five IM conditions were experimentally used in this study, including a part of BRB, 1 BRB, 2 BRBs and 3 BRBs. The new feature extraction and selection approach achieves a higher level of accuracy than the conventional method for motor fault classification, according to the experimental results. Indeed, the results are impressive, and it is capable of detecting the exact number of broken rotor bars under full load conditions
Development of a hardware and software model of a rocket motion correction system
Authors: Atygayev Talgat , Ivel Victor , Gerasimova Yulia
Published: July 2021

The paper deals with the development of a motion correction system for an unguided rocket of a certain class. The existing method for calculating the rocket flight range based on the dependence of flight path on the initial rocket pitch angle and average parameters of disturbing effects does not provide the required accuracy of the specified flight range. This is mainly due to uncontrolled range wind deviations in the flight area. At the same time, conducting test rocket launches to identify dispersion characteristics and improve the target accuracy leads to significant material costs. Therefore, computer simulation is the most promising approach for studying rocket dispersion laws and developing a motion correction system for the unguided rocket on this basis. When developing the correction system, classical differential equations were used describing the aerodynamics of a variable-mass rocket, as well as adaptive control methods with a reference model. As a result of the study, a method for recording a program that implements the reference model on the Arduino Due platform was developed. A general Simulink model that simulates the process of rocket flight path correction was built. A half-scale rocket flight model with a correction block was developed. Based on this model, a series of experiments were carried out, which showed a high degree of rocket target accuracy due to rocket path correction. The results make it possible to take the developed system as a basis for developing a practical path correction system for Grad rockets
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.
Hybrid gene selection method based on mutual information technique and dragonfly optimization algorithm
Authors: Mahmood Sarah Ghanim , Karyakos Raed Sabeeh , Yacoob Ilham M.
Published: July 2021

One of the most prevalent problems with big data is that many of the features are irrelevant. Gene selection has been shown to improve the outcomes of many algorithms, but it is a difficult task in microarray data mining because most microarray datasets have only a few hundred records but thousands of variables. This type of dataset increases the chances of discovering incorrect predictions due to chance. Finding the most relevant genes is generally the most difficult part of creating a reliable classification model. Irrelevant and duplicated attributes have a negative impact on categorization algorithms’ accuracy. Many Machine Learning-based Gene Selection methods have been explored in the literature, with the aim of improving dimensionality reduction precision. Gene selection is a technique for extracting the most relevant data from a series of datasets. The classification method, which can be used in machine learning, pattern recognition, and signal processing, will benefit from further developments in the Gene selection technique. The goal of the feature selection is to select the smallest subset of features but carrying as much information about the class as possible. This paper models the gene selection approach as a binary-based optimization algorithm in discrete space, which directs binary dragonfly optimization algorithm «BDA» and verifies it in a chosen fitness function utilizing precision of the dataset’s k-nearest neighbors’ classifier. The experimental results revealed that the proposed algorithm, dubbed MI-BDA, in terms of precision of results as measured by cost of calculations and classification accuracy, it outperforms other algorithms
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 concept for building a critical infrastructure facilities security system
Authors: Yevseiev Serhii , Melenti Yevgen , Voitko Oleksandr , Hrebeniuk Vitalii , Korchenko Anna , Mykus Serhii , Milov Oleksandr , Prokopenko Oleksandr , Sievierinov Оleksandr , Chopenko Dmytro
Published: July 2021

To effectively protect critical infrastructure facilities (CIF), it is important to understand the focus of cybersecurity efforts. The concept of building security systems based on a variety of models describing various CIF functioning aspects is presented.
The development of the concept is presented as a sequence of solving the following tasks. The basic concepts related to cyberattacks on CIF were determined, which make it possible to outline the boundaries of the problem and determine the level of formalization of the modeling processes. The proposed threat model takes into account possible synergistic/emergent features of the integration of modern target threats and their hybridity. A unified threat base that does not depend on CIF was formed. The concept of modeling the CIF security system was developed based on models of various classes and levels. A method to determine attacker's capabilities was developed. A concept for assessing the CIF security was developed, which allows forming a unified threat base, assessing the signs of their synergy and hybridity, identifying critical CIF points, determining compliance with regulatory requirements and the state of the security system. The mathematical tool and a variety of basic models of the concept can be used for all CIFs, which makes it possible to unify preventive measures and increase the security level. It is proposed to use post-quantum cryptography algorithms on crypto-code structures to provide security services. The proposed mechanisms provide the required stability (230–235 group operations), the rate of cryptographic transformation is comparable to block-symmetric ciphers (BSC) and reliability (Perr 10–9–10–12)
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
Improving the ship's power plant automatic control system by using a model-oriented decision support system in order to reduce accident rate under the transitional and dynamic modes of operation
Authors: Voytetsky Igor , Voytetskaya Taisiya , Vyshnevskyi Leonid , Kozyryev Igor , Maksymova Oksana , Maksymov Maksym , Kryvda Viktoriia
Published: July 2021

This paper proposes a method to improve the performance of a ship's power plant by reducing accidents within it under transitional operating modes. The method is based on decreasing the number of service personnel errors by using a model-oriented decision support system. In order to implement the proposed method, the structure of the system of automatic control of the ship's power plant has been improved. Such an improvement of the control system implied the integration of a modeling unit and a decision support unit into its structure. The modeling unit makes it possible to predict values of the controlled parameters under a transition mode of operation before they actually appear in the system as a result of the operator's actions. A mathematical model of the automatic control system under transitional operating modes has been built for this unit. In order to implement the decision support unit, a method has been devised to formalize the task of managing the power plant under transitional operating modes. The method essentially involves modeling a transitional operating regime, followed by an evaluation of the results based on regulatory requirements and an empirical criterion for assessing the quality of enabling the diesel generators to work in parallel. In addition, a method has been developed for the decision support unit to reduce the accident rate and improve performance with the help of a mathematical apparatus of fuzzy inference, fuzzy logic, and fuzzy sets. Transitional operating regimes resulting from actual erroneous operator actions during ship flights were investigated. As a result of using the proposed system, the power plant performance increases
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.
Features in the formation of the structural state of low-carbon micro-alloyed steels after eletron beam welding
Authors: Laukhin Dmytro , Poznyakov Valerii , Kostin Valery , Beketov Olexander , Rott Nataliіa , Slupska Yuliia , Dadiverina Lilia , Liubymova-Zinchenko Olga
Published: July 2021

Welding thermomechanically-strengthened materials is accompanied with certain difficulties in terms of loss of strength characteristics in the zone of thermal influence. This issue can be resolved by using the technological welding schemes that include fusion of materials in a narrow contact area. One such technological scheme is electron beam welding, which is currently widely used to fabricate structures from refractory and chemically active materials. One of the main advantages of the electron beam welding process is a small quantity of heat input, which leads to the formation of narrow zones of melting and thermal influence and, as a result, minor deformities in the structure of the material. The welded joint can structurally be divided into several zones, which differ in the morphological characteristics of the structure. The most interesting, in terms of ensuring the quality of the joint, are the boundaries between the zones. It has been shown that the use of local heating sources, which is the case at electron beam welding, leads to the migration of the boundaries of grains. As a result, clear intersections, fusion lines, form at the boundaries between zones of the welded joint. The formation of the structural state of a welded joint is predetermined by the simultaneous course of several processes. First, a crystallization from the liquid state – the formation of a welded joint structure, as well as the boundary between a welded joint and the zone of thermal influence. Second, the phase-structural transformations in the solid state – a thermal impact zone, the boundary between a thermal impact zone and the main metal. Given this, one should note that the geometry and quality of joints at electron beam welding are more interrelated than in other welding techniques. Thus, one of the main parameters that ensure the quality of a welded joint is the structural state of the material that forms during welding
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.
Development of a rheological model of stress relaxation in the structure of an oil film on the friction surface with fullerene additives
Authors: Kravtsov Andrii , Suska Anastasiia , Biekirov Abliatif , Levkin Dmytro
Published: July 2021

A rheological model of stress relaxation in a thin lubricant film, which is formed on the friction surface under the influence of the force field of the friction surface in the presence of fullerene compositions in lubricants, was developed. Analysis of the model made it possible to establish that the existence of elastic or viscous properties in surface structures depends on the ratio of two parameters. This is the time of stress relaxation in the structure on spots of actual contact and the duration of stress action on these spots, which is termed the lifetime of an actual contact spot.
It was shown that an increase in the sliding rate reduces the time of relaxation of stresses in the surface structure. This is due to the destruction of aggregates in the structure of gel and the appearance of rotational movements of separate units ‒ flocs. An increase in the load on the tribosystem significantly increases the value of relaxation time. This is due to squeezing the viscous component out of the structure of a surface film. It was established that if the relaxation time exceeds the duration of actions of stresses on actual contact spots, the structure of a surface film behaves like an elastic solid. Conversely, if relaxation time becomes shorter than the duration of stress action, the film behaves like a viscous medium.
Theoretically, it was shown that in the range of sliding and loading rates, when a film behaves like an elastic solid, a decrease in stresses on actual contact spots does not exceed the values of 1.1‒22.8 %. This property provides the bearing capacity of a film. The development of the model will make it possible to simulate elastic and viscous properties of "stitched" structures and substantiate the rational concentrations of additives to lubricants, as well as the ranges of their use.
Compiling invest-oriented integrated reporting: advantages, standards, recommendations
Authors: Momot Tetiana , Karpushenko Maria , Sobolieva Hanna , Lytovchenko Olena , Filatova Iryna
Published: July 2021

Meeting the information needs of investors interested in acquiring a share of the enterprise, or individual intangible assets, the rights to use them, has led to the search for new concepts and models for compiling reporting information. It is important to know how the technologies used by an enterprise affect the environmental condition, what costs are necessary for personnel training, for staying competitive, etc. Under such conditions, the classic model of financial reporting does not meet modern requirements – it is retrospective in nature. To persuade investors to invest in companies focused on creating value, it is important to compile investment-oriented corporate reporting.
This paper reports the devised theoretical and methodological provisions, as well as the substantiation of practical recommendations for compiling investment-oriented integrated reporting, which includes a sequence of activities and a system of indicators for assessing the financial and non-financial components of business operations, including indicators of the environmental and social activities of an enterprise, which ensures the transparency of information in terms of business risks and their management.
It is stated that the main goal of investment-oriented corporate reporting is to inform users about increasing the company's market value. Indeed, the reflection of the importance of social and environmental priorities, attention paid and efforts applied made to resolve social issues give confidence in the reliability of business and stimulate the attraction of investment resources. The examples of the companies chosen for this study have proven that the submission of complete information based on the groups of non-financial indicators of integrated reporting is a factor in increasing the market value of the company, and, accordingly, enhancing its investment attractiveness.
The devised proposals make it possible to summarize in a single format information about the activities of an enterprise, related risks, and its investment potential
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.