bluuebunny/crossref_metadata_2025 huggingface dataset:
Disposições, hábitos e provas
Authors: Vieira de Assis Rodrigo
Published: May 2021

O objetivo deste artigo é o de problematizar algumas das principais vertentes das sociologias do indivíduo com a intenção de colaborar para uma melhor compreensão dos conceitos e métodos que têm sido mobilizados para a objetivação sociológica da existência individual. São discutidas três perspectivas centrais deste campo: a teoria da ação de Bernard Lahire, a teoria dos hábitos de Jean-Claude Kaufmann e a teoria da individuação de Danilo Martuccelli. A escolha desses autores considerou o tipo similar da prática sociológica que realizam, sustentada numa contínua relação entre a pesquisa e a teorização original. O artigo apresenta as contribuições das sociologias do indivíduo para a teoria sociológica contemporânea, sublinhando-as como parte de um campo teórico-metodológico heterogêneo ainda em desenvolvimento.
Psicopolítica e mal-estar da contemporaneidade
Authors: Delazeri Mocellim Alan
Published: May 2021

Em O mal-estar da civilização Freud buscou apresentar uma discussão sobre os ganhos e as perdas da civilização, e em específico sobre o mal-estar causado por suas limitações. Para Elias (1993; 2011), a civilização, como prática, envolve o controle das condutas, a regulação dos modos e a subordinação das emoções. O tormento trazido pela civilização decorre do modo pelo qual ela limita a liberdade, se sobrepondo aos impulsos, impondo tarefas culturais acima das vontades individuais. A civilização é a repressão social se tornando uma cobrança constante e internalizada como mal-estar. Nesse artigo busco articular sociologicamente, em contraposição a diversos autores da teoria social, o conjunto de hipóteses levantadas por Byung-Chul Han (2018b) sobre a psicopolítica, de modo a repensar os rumos e as transformações do mal-estar em uma sociedade não repressiva (fundada em negatividade), mas afirmativa (fundada em positividade).
Existências conjuntas e seus trajetos
Authors: Rabelo Miriam C. M. , Souza Iara Maria
Published: May 2021

Neste trabalho discutimos diferentes modos de existir-junto ou, mais especificamente, como certos seres se juntam em trajetórias de enredamento. A ideia, proposta por Souriau, de que as existências são não só plurais como também sempre capazes de tornar-se outras, de ganhar (ou perder) intensidade, constitui o ponto de partida de nossa reflexão. As formas de existir-junto de que falaremos aqui provêm de nossos diferentes campos de pesquisa (relações entre humanos e animais outros que humanos em um laboratório de pesquisa; relações entre seres mais que humanos e seus filhos humanos nas religiões afro-brasileiras). Interessa-nos refletir sobre os trajetos e técnicas através dos quais essas formas brotam e se fortalecem nesses campos.
The current state of the methods for calculating global illumination in tasks of realistic computer graphics
Authors: Frolov Vladimir , Voloboy Alexey Gennadievich , Ershov Sergey Valentinovich , Galaktionov Vladimir Alexandrovich
Published: May 2021

Modern realistic computer graphics are based on light transport simulation. In this case, one of the main and difficult to calculate tasks is to calculate the global illumination, i.e. distribution of light in a virtual scene, taking into account multiple reflections and scattering of light and all kinds of its interaction with objects in the scene. Hundreds of publications and describing dozens of methods are devoted to this problem. In this state-of-the-art review, we would like not only to list and briefly describe these methods, but also to give some “map” of existing works, which will allow the reader to navigate, understand their advantages and disadvantages, and, thereby, choose a right method for themselves. Particular attention is paid to such characteristics of the methods as robustness and universality in relation to the used mathematical models, the transparency of the method verification, the possibility of efficient implementation on the GPU, as well as restrictions imposed on the scene or illumination phenomena. In contrast to the existing survey papers, not only the efficiency of the methods is analyzed, but also their limitations and the complexity of software implementation. In addition, we provide the results of our own numerical experiments with various methods that serve as illustrations for the conclusions.
Mu-Calculus Satisfiability with Arithmetic Constraints
Authors: Limón-Priego Yensen , Bárcenas-Patiño Ismael Everardo , Benítez-Guerrero Edgard Iván , Molero-Castillo Guillermo Gilberto , Velazquez-Mena Alejandro
Published: May 2021

The propositional modal μ-calculus is a well-known specification language for labeled transition systems. In this work, we study an extension of this logic with converse modalities and Presburger arithmetic constraints, interpreted over tree models. We describe a satisfiability algorithm based on breadth-first construction of Fischer-Lardner models. An implementation together several experiments are also reported. Furthermore, we also describe an application of the algorithm to solve static analysis problems over semi-structured data.
Classification of Depressive Episodes Using Nighttime Data: Multivariate and Univariate Analysis
Authors: Rodríguez-Ruiz Julieta G. , Galván-Tejada Carlos Eric , Vázquez-Reyes Sodel , Galván-Tejada Jorge Issac , Gamboa-Rosales Hamurabi
Published: May 2021

Mental disorders like depression represent 28% of global disability, it affects around 7.5% percent of global disability. Depression is a common disorder that affects the state of mind, normal activities, emotions, and produces sleep disorders. It is estimated that approximately 50% of depressive patients suffering from sleep disturbances. In this paper, a data mining process to classify depressive and not depressive episodes during nighttime is carried out based on a formal method of data mining called Knowledge Discovery in Databases (KDD). KDD guides the process of data mining with stages well established: Pre-KDD, Selection, Pre-processing, Transformation, Data Mining, Evaluation, and Post-KDD. The dataset used for the classification is the DEPRESJON dataset, which contains the motor activity of 23 unipolar and bipolar depressed patients and 32 healthy controls. The classification is carried out with two different approaches; a multivariate and univariate analysis to classify depressive and non-depressive episodes. For the multivariate analysis, the Random Forest algorithm is implemented with a model construct of 8 features, the results of the classification are specificity equal to 0.9927 and sensitivity equal to 0.9991. The univariate analysis shows that the maximum of the activity is the most descriptive characteristic of the model with 0.908 in accuracy for the classification of depressive episodes.
An effect analysis of cooling water direction towards condensate oil from scrap tires
Authors: Suyitno Budhi M , Pane Erlanda Augupta , Libyawati Wina , Jelita Chatrine , Sukma Hendri , Ismail Ismail
Published: May 2021

The application of pyrolysis for the thermal decomposition of tire waste can be taken as the ideal concept to reduce and recycle tire waste. The product of the process can produce condensate oil, a typical oil that is close to crude oil properties. The critical aspect of the pyrolysis process is the design of the reactor, particularly for the condenser where the rate of heat transfer contributes to the overall quality and quantity of the produced condensate oil. This study focused on the effect of water flow direction on the condensation process of pyrolysis gas. The quantity and quality of the produced oil are examined to observe the effect of the condensation process. Two different water flow directions are tested in the process, namely, counter flow and parallel flow direction. The effect of water flow direction in the condenser clearly affects the pyrolysis process to produce the condensate oil. Based on the production quantity, the counter flow condenser is able to produce 355 ml of condensate oil while the parallel flow one merely 290 ml. Based on the quality of the produced condensate oil, the counter flow condenser is generally better than the parallel flow one where the density, flash point and viscosity are close to crude oil properties. The rate of heat transfer from the condenser to the pyrolysis gas is the main factor that contributes to the quality and quantity of the condensate oil. The average heat transfer for the counter and parallel flow is 2,728 W and 1,865 W, respectively. It can be said that using the counter flow condenser for the pyrolysis reactor can improve the quality and quantity of the condensate oil
Development of white tea extract as green corrosion inhibitor in mild steel under 1 M hydrochloric acid solution
Authors: Kaban Agus Paul Setiawan , Ridhova Aga , Priyotomo Gadang , Elya Berna , Maksum Ahmad , Sadeli Yunita , Sutopo Sutopo , Aditiyawarman Taufik , Riastuti Rini , Soedarsono Johny Wahyuadi
Published: May 2021

This work covers the effectiveness of the White tea extract as a green corrosion inhibitor and is correlated to the strength and stability bonding between the phenolic molecule and the Fe atoms in mild steel and how this interaction can be studied by altering the concentration and temperature. White tea has received considerable attention due to its capability as a corrosion inhibitor and has been extensively studied using electrochemical techniques. However, accurate and systematic functional group identification and surface modification have been missing. Our study sought to demonstrate the quantitative measurement of electrochemical impedance spectroscopy (EIS) complemented by the FTIR (Fourier transform infrared spectroscopy), Total Phenolic Test, and Raman Spectroscopy. The SEM (Scanning Electronic Microscope)/EDX (Energy-Dispersive X-Ray Spectroscopy), and AFM (Atomic Force Microscope) were used to study the surface modification. The EIS results show that the optimum inhibition efficiency was 96 % in a solution of 80 ppm at 60 °C. Acetone 70 % was used to extract White tea and gives 14.17±0.25 % phenolic compound. Spectroscopic studies show -OH, Aromatic C=C, C=O and C-O-C become major contributors in the adsorption process and are found on the surface of metals as corrosion protection. Meanwhile, the thermodynamic calculation shows the White tea was adsorbed chemically. The nearness of R2 to 1 shows the adsorption agrees with the Langmuir adsorption isotherm. Eventually, the surface modification revealed that phenol molecules are responsible to reduce the corrosion rate at 16.38×10-3 mpy. Our results are expected to provide a guideline for future research in White tea as a green corrosion inhibitor
Determining the parameters for a 3D-printing process using the fused deposition modeling in order to manufacture an article with the required structural parameters
Authors: Vambol Oleksii , Kondratiev Andrii , Purhina Svitlana , Shevtsova Maryna
Published: May 2021

The mass application of FDM technology is slowed down due to the difficulty of selecting 3D printing parameters in order to manufacture an article with the required characteristics. This paper reports a study into the impact of 3D printing parameters (temperature, print speed, layer height) on mechanical parameters (strength, elasticity module), as well as on the accuracy of printing and roughness of the surface of a specimen based on thermoplastic (PLA plastic). Several batches of specimens were fabricated for this study in accordance with ASTM D638 and ASTM D695, which were tested for tension, geometric accuracy, and roughness. Based on the experimental data, regression analysis was carried out and the functional dependences of the strength, elasticity module, printing precision, roughness of a surface on 3D printing parameters (temperature, speed, thickness of the layer) were constructed. In addition, the derived mathematical model underlying a method of non-linear programming has established such printing parameters that could provide for the required properties of a structure. The analytical dependences reported in the current work demonstrate a high enough determination factor in the examined range of parameters. Using functional dependences during the design phase makes it possible to assess the feasibility of its manufacture with the required properties, reduce the time to work out the process of printing it, and give recommendations on the technological parameters of 3D printing. The recommendations from this study could be used to make PLA-plastic articles for various purposes with the required properties
Tensile strength and thermal cycle analysis of AA6061 friction weld joints with different diameters and various friction times
Authors: Irawan Yudy Surya , Choiron Moch Agus , Suprapto Wahyono
Published: May 2021

The paper reports measurement of tensile strength and the thermal cycle of AA6061 aluminum alloy circular bar friction weld with different diameters and various friction times. A continuous drive friction welding (CDFW) of AA6061 was conducted to weld the AA6061 circular bar with different diameters of 30 mm for the rotating part and 15 mm for the stationary part. The CDFW process was carried out with the revolution speed of 1,600 rpm, the initial compressive force of 2.8 kN during the friction stage for various friction times of 10, 12, and 14 seconds, and an upset force of 28 kN for 60 seconds. The flash temperature was measured using a digital infrared thermometer gun. Computer simulation using the finite element method was also done by coupling transient thermal and static structural methods. The flash temperature becomes higher along with increasing friction time based on the digital infrared thermometer gun measurement and finite element analysis. The results of tensile strength testing show that the specimen with a friction time of 12 seconds has the highest tensile strength. Based on the hardness testing result, it is found that the specimen with a friction time of 10 seconds has higher hardness, but it has an incomplete joint flash so that the tensile strength is lower than that of the specimen with a friction time of 12 seconds. Besides, the hardness of the specimen with a friction time of 12 seconds is higher than that of the specimen with a friction time of 14 seconds. The flash size becomes bigger along with the increase of the friction time based on the macrostructure observation on the longitudinal section of the CDFW specimen. It is confirmed by the temperature measurement and finite element analysis that the specimen with a friction time of 12 seconds has heat input to form the CDFW joint that has a maximum tensile strength in the range of this study
Analytical study of auto-balancing within the framework of the flat model of a rotor and an auto-balancer with a single cargo
Authors: Filimonikhin Gennadiy , Olijnichenko Lubov , Strautmanis Guntis , Haleeva Antonina , Hruban Vasyl , Lysenko Olexandr , Mezitis Mareks , Valiavskyi Ivan
Published: May 2021

This paper reports the analytically established conditions for the onset of auto-balancing for the case of a flat rotor model on isotropic elastic-viscous supports and an auto-balancer with a single load. The rotor is statically unbalanced, the rotation axis is vertical. The auto-balancer has a single cargo – a pendulum, a ball, or a roller. The balancing capacity of the cargo is equal to the rotor imbalance.
The physical-mathematical model of the system is described. The differential equations of motion are recorded in dimensionless form relative to the coordinate system that rotates synchronously with the rotor. The so-called main movement has been found; in it, the cargo synchronously rotates with the rotor and balances it. The differential equations of motion are linearized in the neighborhood of the main movement. A characteristic equation has been constructed. It helped investigate the stability of the main movement (an auto-balancing mode) for the cases of the absence and presence of resistance forces in the system.
It was established that in the absence of resistance forces in the system:
– the rotor has three characteristic rotational speeds, and the first always coincides with the resonance frequency;
– auto-balancing occurs when the rotor rotates at speeds between the first and second ones, and above the third characteristic speed;
– the value of the second and third characteristic speeds is significantly influenced by the ratio of weight to the mass of the system;
– the second and third characteristic speeds monotonously increase with an increase in the ratio of cargo weight to the mass of the system.
Resistance forces significantly affect both the values of the second and third characteristic speeds and the conditions of their existence. Small resistance forces do not change the quality behavior of the system. With high resistance forces, the number of characteristic speeds decreases to one.
The paper reports the results applicable to an auto-balancer with many cargoes when it balances the imbalance that equals the balancing capacity of the auto-balancer
Development of а matrix of food industry capacity for making management decisions in the formation of sustainable development of agroecosystems
Authors: Andriushchenko Kateryna , Datsii Oleksandr , Lavruk Oksana , Dmytrenko Ruslan , Kutashev Igor , Vіnіchenko Igor , Mishchenko Dmytro , Kakhovych Yulia , Pivovarov Konstantin , Ortina Ganna
Published: May 2021

A theoretical and methodological study was carried out to determine the need and features of developing a matrix of food industry capacity for making management decisions in the formation of sustainable development of agroecosystems, which will increase the operational efficiency of companies and food security of the country. The paper uses the following research methods: historical – in the process of studying modern views on understanding the importance of the agricultural sector for the economy; system analysis – when building a model of innovative business improvement. Methods of comparison and analysis of trends – the study of trends in the agricultural sector of Ukraine with the identification of important areas for improving their activities. Methods of financial analysis – for the analytical assessment of financial and economic activities of the investigated enterprises; forecasting methods – to substantiate the expected results of implementing the author's proposals in management practice. It is proposed to take into account the significant difference in the technology of their processing and production (number of advanced technologies used per 100 thousand people). The paper reveals the dependence of production technologies in agriculture on natural and weather conditions (share of technological innovation costs, %). Criteria for innovation skills in the development of agricultural engineering were proposed. The criteria were determined, which were divided into development groups. The tools for constructing a matrix of food industry capacity were substantiated. Note that for each indicator, the optimal value was determined taking into account the sensitivity factor and the rating of enterprises, which determined their place in the matrix. In the course of the study and the matrix of innovative development, the proposed technology was tested at leading domestic enterprises
Computer simulation of logarithmic transformation function to expand the range of high-precision measurements
Authors: Shcherban’ Volodymyr , Korogod Ganna , Kolysko Oksana , Kolysko Mariana , Shcherban’ Yury , Shchutska Ganna
Published: May 2021

Studies of the effect of normalized radiation fluxes on the measurement result revealed the most influential one. The value of the normalized flow F0 was shown to have a greater effect on the relative measurement error than ΔF0. This allows investigating the relationship between the controlled Fx and the normalized flow F0. Experimental studies have confirmed that by a threefold increase in the normalized flow F0 relative to the controlled flow Fx, it becomes possible to increase the measurement accuracy in a wide range. In particular, it was found that at the flux value F0=0.16×10-3 W, it becomes possible to measure the controlled flow in a wider range Fх=(0.16×10-3÷0.97×10-3) W with a relative error of thousandths of a percent. The effect of the reproduction error on the measurement result under the condition of a threefold increase in the normalized flow F0 relative to the controlled flow Fх is shown. It was found that an increase in the reproduction error of the normalized radiation fluxes by 1 order leads to a narrowing of the range in which the value of the relative error tends to zero. It is shown that in the absence of a threefold increase in the normalized flow F0, an increase in the reproduction error of the normalized flows by 1 order leads to individual cases of reduction in the relative error to small-order values. The latter, by the way, applies to cases where the ratio between the normalized F0 and controlled flow Fx, as 3 to 1, is ensured. It is shown that the reproduction error of the dark flow does not affect the measurement result.Thus, there is reason to believe that it is possible to expand the measurement range, in which the value of the relative error is thousandths of a percent, even for 1 measurement cycle
Devising an entropy-based approach for identifying patterns in multilingual texts
Authors: Yerkebulan Gulnur , Kulikova Valentina , Kulikov Vladimir , Kulsharipova Zaru
Published: May 2021

Even though the plagiarism identification issue remains relevant, modern detection methods are still resource-intensive. This paper reports a more efficient alternative to existing solutions.
The devised system for identifying patterns in multilingual texts compares two texts and determines, by using different approaches, whether the second text is a translation of the first or not. This study's approach is based on Renyi entropy.
The original text from an English writer's work and five texts in the Russian language were selected for this research. The real and "fake" translations that were chosen included translations by Google Translator and Yandex Translator, an author's book translation, a text from another work by an English writer, and a fake text. The fake text represents a text compiled with the same frequency of keywords as in the authentic text.
Upon forming a key series of high-frequency words for the original text, the relevant key series for other texts were identified. Then the entropies for the texts were calculated when they were divided into "sentences" and "paragraphs".
A Minkowski metric was used to calculate the proximity of the texts. It underlies the calculations of a Hamming distance, the Cartesian distance, the distance between the centers of masses, the distance between the geometric centers, and the distance between the centers of parametric means.
It was found that the proximity of texts is best determined by calculating the relative distances between the centers of parametric means (for "fake" texts ‒ exceeding 3, for translations ‒ less than 1).
Calculating the proximity of texts by using the algorithm based on Renyi entropy, reported in this work, makes it possible to save resources and time compared to methods based on neural networks. All the raw data and an example of the entropy calculation on php are publicly available
Improving the algorithm of choosing spacing and number of stiff supports against a concentrated force in steel-concrete beams
Authors: Petrov Anatoliy , Paliy Andriy , Naumenko Artem , Sheptun Serhii , Ihnatenko Maryna , Vysochin Ivan , Kononenko Yana , Yurchenko Oksana , Dedilova Tetiana , Paliy Anatoliy
Published: May 2021

A steel-concrete beam was taken as the study object. The algorithm of selecting the number of stiff supports for the steel-concrete beam loaded with a concentrated lateral force in the middle of the span has been refined. Stiff supports served to join the steel strip with concrete to ensure their joint performance. The algorithm was refined based on the condition of equality of the longitudinal force in the steel strip from the action of the calculated load and the maximum longitudinal force obtained after setting the supports. In this case, the longitudinal forces in all stiff supports, as well as the spacing of the stiff supports should be the same.
A disadvantage of the known algorithm consists in the complexity of determining the coefficient φb2 taking into account the effect of long-term concrete creep on the element deformation without cracks. This coefficient fluctuates widely and depends on many factors. Besides, it is also insufficiently studied.
Calculations for determining the number and spacing of stiff supports in a steel-concrete beam were conducted according to the proposed algorithm and in the Lira software package. The forces acting on the supports and spacing of the supports were the same. The force acting in the support was 8941.5 N. When selecting characteristics of the steel-concrete beam, maximum longitudinal force in the steel strip was obtained. The longitudinal force amounted to 35726 N. The same longitudinal force was obtained from the diagram of longitudinal forces obtained after setting the supports.
This study was aimed at improving the design of steel-concrete beams. A rational number and placement of stiff supports ensure savings: the required amount of building materials is reduced and their cost is reduced due to cutting labor costs for their manufacture and operation
Analyzing the drivers of sustainable value creation, partnership strategies, and their impact on business competitive advantages of small & medium enterprises: a PLS-model
Authors: Hariastuti Ni Luh Putu , Pratikto Pratikto , Santoso Purnomo Budi , Tama Ishardita Pambudi
Published: May 2021

Sustainable manufacturing is a critical phenomenon in the process of creating sustainable value. This is a way to increase innovation and resource quality. On the other hand, the partnership strategy is an important factor in efforts to improve company performance. The involvement of the partnership strategy is one of the factors that strengthen the achievement of sustainable values. Furthermore, this affects the sustainability of a manufacturing company's competitiveness, including Small and Medium Enterprises (SMEs). In this study, we focus on creating sustainable value and the role of partnership strategies in improving the business performance of SMEs engaged in the metal manufacturing industry. The Partial Least Squares (PLS) approach to Structural Equation Modeling (SEM) is used to evaluate relationships and effects based on survey data from small and medium industries. The results show that the creation of sustainable value, including products, processes, production, equipment, organization, and human values, has a significant impact (β=0.522; ρ<0.001) on increasing the competitiveness of small and medium enterprises. The effect of sustainable value creation on sustainable competitiveness is fully moderated by the partnership strategy (β=0.179; ρ=0.03), especially in the technology & equipment, and human resources. Apart from being a moderating variable, the partnership strategy has also been shown to significantly act as a partial mediating variable (β=0.135; ρ<0.05) for sustainable value creation in enhancing competitiveness. The partnership strategy's simultaneous involvement proves that the partnership strategy plays an important role in value creation to increase the competitiveness of sustainable manufacturing SMEs
Determining the effect of treating table beet with biopreparations before storage on its preservation
Authors: Pusik Ludmila , Pusik Vlаdimir , Bondarenko Veronika , Gaevaya Ludmila , Lyubymova Nina , Sukhova Galyna , Didukh Nataliya , Slobodyanyk Galina
Published: May 2021

The study reported here aimed to explore the preservation of table beet depending on its treatment with bio preparations before storage in order to prolong its shelf life.
The effect of aqueous solutions of the biopreparations Phytosporine and Gamair in concentrations of 0.2 %, 0.3 %, and 0.5 % on the intensity of quality loss by beetroots during storage was investigated.
It was found that the treatment with the bio preparations reduced the total weight loss by the roots Zepo F1 by 7.9‒10.3 %, Carillon F1 ‒ by 6.8‒7.7 %. The daily weight loss by untreated beetroots due to the damage induced by microorganisms ranged from 0.08±0.01 % at a storage temperature of 1±1 °С to 0.1±0.01 % at a storage temperature of 15±1 °С, respectively.
The sugar content in beetroots non-treated with bio preparations decreases during storage by 21.6–25.0 %. Treating beetroots with a 0.3 % solution of Phytosporine reduces sugar losses over 150 days at a storage temperature of 1±1 °С by 3.7–6.5 %; with a 0.3 % Gamair solution ‒ by 8.8–12.8 %.
The loss of vitamin C ranged from 39.4 % to 41.2 % relative to the initial content in the control. The treatment with Phytosporine reduced the loss of vitamin C to 17.4 % in Zepo F1, and 25.4 % ‒ in Carillon F1; with Gamair ‒ to 28.0 and 29.3 %, respectively. At a storage temperature of 15±1 °С, the content of vitamin C decreased by 1.5‒1.8 times over 90 days.
It was established that the preservation of table beet depends on the shape of a root. At a storage temperature of 1±1 °С, the weight loss by cylindrical beetroots is 5.1 %, rounded shape ‒ 5.4 %. The yield of marketable products ranges from 74.2 to 82.9 % for the Carillon F1 hybrid, and for Zepo F1 of a round shape ‒ 73.3–80.5 % depending on the storage temperature.
The technique of treating table beet before storage with bio preparations allows using Phytosporine and Gamair for post-harvest treatment of vegetable raw materials. When devising new, low-cost, environmentally friendly, and affordable technologies, this is an important tool.
Development of an optimization method for measuring the Doppler frequency of a packet taking into account the fluctuations of the initial phases of its radio pulses
Authors: Yevseiev Serhii , Kuznietsov Oleksandr , Herasimov Sergey , Horielyshev Stanislav , Karlov Anton , Kovalov Ihor , Kolomiitsev Oleksii , Lukashuk Olena , Milov Oleksandr , Panchenko Vitaliy
Published: May 2021

The necessity of estimating the decrease in the accuracy of measuring the informative parameters of a radar signal in real conditions of its propagation and reflection has been substantiated. The results of the estimation determine the requirements for optimizing this measurement to achieve the required efficiency. A numerical analysis of the decrease in the accuracy of measuring the Doppler frequency of a coherent packet is presented, depending on the statistical characteristics of fluctuations of the initial phases of its radio pulses. Expressions are given for calculating the fluctuation component of the measurement error of radio pulse packet frequency for various coefficients of interpulse correlation of phase fluctuations. An assessment is made of the possibility of increasing the accuracy of Doppler frequency measurement, which can be ensured by statistical optimization of the algorithm for time-frequency processing of a given radar signal by taking into account its phase fluctuations. The conditions for the multiplicative influence of phase fluctuations of radio pulses of the received packet are substantiated, which determine the efficiency of optimization of Doppler frequency measurement.
Based on the results of the study, an optimization method for measuring the Doppler frequency of the packet taking into account fluctuations in the initial phases of its radio pulses is proposed. The accuracy of Doppler frequency measurement under the influence of both the internal noise of the radar receiver and the correlated phase fluctuations of its radio pulses is estimated. The efficiency of optimization of measuring the Doppler frequency of the packet is estimated taking into account fluctuations of the initial phases of its radio pulses by means of computer simulation. It is proved that, under the influence of phase fluctuations, the accuracy of Doppler frequency measurement can be increased due to the performed optimization from 1.86 to 6.29 times. This opens the way to improving the existing algorithms for measuring the higher time range derivatives to improve the quality of tracking complex maneuvering aerodynamic objects. This explains the importance and usefulness of the work for the radar theory.
Navigation safety control system development through navigator action prediction by data mining means
Authors: Nosov Pavlo , Zinchenko Serhii , Ben Andrii , Prokopchuk Yurii , Mamenko Pavlo , Popovych Ihor , Moiseienko Vladyslav , Kruglyj Dmytro
Published: May 2021

Taking into account current trends in the development of ergatic maritime transport systems, the factors of the navigator’s influence on vessel control processes were determined. Within the framework of the research hypothesis, to improve navigation safety, it is necessary to apply predictive data mining models and automated vessel control.
The paper proposes a diagram of the ergatic vessel control system and a model for identifying the influence of the navigator “human factor” during navigation. Within the framework of the model based on the principles of navigator decision trees, prediction by data mining means is applied, taking into account the identifiers of the occurrence of a critical situation. Based on the prediction results, a method for optimal vessel control in critical situations was developed, which is triggered at the nodes of the navigator decision tree, which reduces the likelihood of a critical impact on vessel control.
The proposed approaches were tested in the research laboratory “Development of decision support systems, ergatic and automated vessel control systems”. The use of the Navi Trainer 5,000 navigation simulator (Wärtsilä Corporation, Finland) and simulation of the navigation safety control system for critical situations have confirmed its effectiveness. As a result of testing, it was determined that the activation of the system allowed reducing the likelihood of critical situations by 18–54 %. In 11 % of cases, the system switched the vessel control processes to automatic mode and, as a result, reduced the risk of emergencies.
The use of automated data mining tools made it possible to neutralize the negative influence of the “human factor” of the navigator and to reduce the average maneuvering time during vessel navigation to 23 %
Solving a one mixed problem in elasticity theory for half-space with a cylindrical cavity by the generalized Fourier method
Authors: Ukrayinets Nataliia , Murahovska Olena , Prokhorova Olha
Published: May 2021

Designing and constructing underground structures for various purposes, such as tunnels, mines, mine workings, necessitate the development of procedures for calculating their strength and reliability. The physical model of such objects worth considering is a homogeneous isotropic half-space that contains an infinitely long hollow cylinder, located parallel to its border. One can explore problems related to the mechanics of deformable solids for such a multiply connected body.
This paper reports the proofs of addition theorems for the basic solutions to the Lamé equation regarding the half-space and cylinder recorded, respectively, in the Cartesian and cylindrical coordinate systems. This result is important from a theoretical point of view in order to substantiate a numerical-analytical method ‒ the generalized Fourier method. This method makes it possible to solve spatial boundary problems from the theory of elasticity and thermo-elasticity for isotropic and transversal-isotropic multiply connected bodies. Similar to the classical Fourier method, the general solutions to equilibrium equations have been used here but in several coordinate systems rather than one.
From a practical point of view, this method has made it possible to investigate the combined problem of elasticity theory regarding the multiply-connected body described above. The analysis of the stressed-strained state of this elastic body has made it possible to draw conclusions on determining those regions that are most vulnerable to destruction. The highest values are accepted by normal stresses in the region between the boundaries of the half-space and the cylinder. Changing the σy component along the Ox axis corresponds to the displacements assigned on the half-space. The τxy component contributes less to the distribution of stresses than σx and σy. The applied aspect of using the reported results is the possibility to apply them when designing underground structures
Design of impact dampers for transporting cargoes by two-link vehicles
Authors: Vikovych Ihor , Krainyk Ljubomyr , Zinko Roman , Popovych Vitalij , Horbai Orest
Published: May 2021

This paper considers the influence of the transitional modes of movement (acceleration, braking) of a multi-link vehicle on the vibration protection of transported non-fixed or partially fixed cargoes. The impact phenomenon, in this case, can be strengthened by the existence of coupling mechanisms between the links of a multi-link vehicle. To reduce such horizontal impact loads, it is advisable to use elements with viscoelastic damping in the coupling devices of a multi-link vehicle. To study the actual impact phenomena during the transportation of non-fixed or partially fixed cargoes under the extreme modes of movement of two-link vehicles, it is proposed to use a flat two- and three-mass dynamic model with viscoelastic damping. At the same time, the theory of elastic impact has been applied while the elastic-damping characteristics of vehicles' suspensions were not taken into consideration.
It has been shown that the reported research results make it possible to estimate the approximate values of the mechanical parameters for restrictive devices that protect non-fixed or partially fixed cargoes from impact, during the transition modes of transportation, depending on the conditions of motion.
This practically makes it possible to select the rational design parameters for the elements of viscoelastic restrictive devices, in particular elastic elements and dampers, in order to reduce impact loads on non-fixed heavy cargoes during transportation under extreme modes of movement.
Based on this study, a procedure of vibration protection of non-fixed or partially fixed cargoes in the body of a two-link vehicle during its uneven movement has been proposed, which implies determining the maximum dynamic loads on these cargoes as well as the possibility of choosing the rational design parameters for restrictive devices in order to prevent or reduce the impact of these cargoes hitting the restrictive devices
Regularities in the washing out of water-soluble phosphorus-ammonium salts from the fire-protective coatings of timber through a polyurethane shell
Authors: Tsapko Yuriy , Vasylyshyn Roman , Melnyk Oleksandr , Lomaha Vasyl , Tsapko Аleksii , Bondarenko Olga
Published: May 2021

The analysis of fire-protective materials for wooden building structures was carried out and the need to develop reliable methods for studying the process of washing out fire retardants from the surface of the building structure, which is necessary for the creation of new types of fire-protective materials, was established. That is why there arises a need to determine the conditions for the formation of a barrier for washing out and to establish a mechanism for inhibition of moisture transmission to the material. In this regard, a mathematical model was built of washing out fire retardants using a polymeric shell made of organic material as a coating, which makes it possible to estimate the effectiveness of a polymer shell by the amount of the washed-out fire retardant. According to the experimental data and theoretical dependences, the dynamics of the release of fire retardants from the fire-protective layer of the coating was calculated; it did not exceed 1.0 %, and therefore, ensures fire protection of timber. The results of determining the weight loss of the sample under the influence of water indicate the ambiguous impact of the nature of protection on the washout. In particular, this implies the availability of data sufficient for performing a high-quality process of moisture diffusion inhibition and, based on it, detection of the moment, from which a decrease in efficiency of a coating begins. The experimental studies proved that a sample of fire-protected timber after exposure to water for 30 days withstood the influence of a heat flow. In particular, the loss of timber weight after the temperature exposure was less than 6 %, and the temperature of flue gases did not exceed 185 °C. Thus, there is a reason to assert the possibility of directed control of the processes of fire protection of timber through the use of polymer coatings capable of forming a protective layer on the surface of fire-protected material, which inhibits the rate of washing out the fire retardants
Development of a method to improve the calculation accuracy of specific fuel consumption for performance modeling of air-breathing engines
Authors: Kislov Oleh , Ambrozhevich Maya , Shevchenko Mykhailo
Published: May 2021

Determination of specific fuel consumption of air-breathing engines is one of the problems of modeling their performance. As a rule, the estimation error of the specific fuel consumption while calculating air-breathing engine performance is greater than that of thrust. In this work, this is substantiated by the estimation error of the fuel-air ratio, which weakly affects thrust but significantly affects the specific fuel consumption. The presence of a significant error in the fuel-air ratio is explained by the use of simplified methods, which use the dependence of enthalpy as a function of mixture temperature and composition without taking into account the effect of pressure. The developed method to improve the calculation accuracy of specific fuel consumption of air-breathing engines is based on the correction of the fuel-air ratio in the combustor, determined by the existing mathematical models. The correction of the fuel-air ratio is made using the dependences of enthalpy on mixture temperature, pressure and composition. The enthalpy of the mixture is calculated through the average isobaric heat capacity obtained by integrating the isobaric heat capacity, depending on mixture temperature, pressure and composition. The calculation accuracy of the fuel-air ratio was verified by comparing it with the known experimental data on the combustion chamber of the General Electric CF6-80A engine (USA). The average calculation error of the fuel-air ratio does not exceed 3 %. The developed method was applied for correcting the specific fuel consumption for calculating the altitude-airspeed performance of the D436-148B turbofan engine (Ukraine), which made it possible to reduce the estimation error of the fuel-air ratio and specific fuel consumption to an average of 3 %
Devising a method for finding a family of membership functions to bifuzzy quantities
Authors: Raskin Lev , Sira Oksana , Sukhomlyn Larysa , Korsun Roman
Published: May 2021

This paper has considered a task to expand the scope of application of fuzzy mathematics methods, which is important from a theoretical and practical point of view. A case was examined where the parameters of fuzzy numbers’ membership functions are also fuzzy numbers with their membership functions. The resulting bifuzziness does not make it possible to implement the standard procedure of building a membership function. At the same time, there are difficulties in performing arithmetic and other operations on fuzzy numbers of the second order, which practically excludes the possibility of solving many practical problems. A computational procedure for calculating the membership functions of such bifuzzy numbers has been proposed, based on the universal principle of generalization and rules for operating on fuzzy numbers. A particular case was tackled where the original fuzzy number’s membership function contains a single fuzzy parameter. It is this particular case that more often occurs in practice. It has been shown that the correct description of the original fuzzy number, in this case, involves a family of membership functions, rather than one. The simplicity of the proposed and reported analytical method for calculating a family of membership functions of a bifuzzy quantity significantly expands the range of adequate analytical description of the behavior of systems under the conditions of multi-level uncertainty. A procedure of constructing the membership functions of bifuzzy numbers with the finite and infinite carrier has been considered. The method is illustrated by solving the examples of using the developed method for fuzzy numbers with the finite and infinite carrier. It is clear from these examples that the complexity of analytic description of membership functions with hierarchical uncertainty is growing rapidly with the increasing number of parameters for the original fuzzy number’s membership function, which are also set in a fuzzy fashion. Possible approaches to overcoming emerging difficulties have been described.
Hydrological-stenobiontic method for determining environmental flows from reservoir
Authors: Bezsonov Yevhen , Muntian Liliia , Krysinska Diana
Published: May 2021

In the practice of using river resources accumulated in reservoirs, there is a typical problem of unreasonably large water intake for industrial-household needs to the detriment of the aquatic ecosystem. An important tool for balancing these links is to provide environmental flows based on a comprehensive analysis of river functioning patterns. And in terms of a progressing negative impact of reservoirs on the integrity of river ecosystems, the choice of indicator hydrobiota for the calculation of environmental flows should be considered insufficiently substantiated. The solution of this problem, by filling the appropriate methodological niche, allowed substantiating the hydrological-stenobiontic method for determining environmental flows. The developed solutions are based on the minimum possible values of tolerance of aquatic ecosystems stenobionts to water velocity. Five groups of macrozoobenthos represent relevant target organisms. The hydrological calculations presented in the paper are based on the data of daily water flow rate for 80 years and the results of field studies of the river channel depth in the low water period. On this basis, it was determined that for lowland parts of rivers, the flow velocity in the tailwater of reservoirs should be at least 0.2 m/s. Comparison of the curve of the average monthly water velocity dynamics of 95 % runoff availability with the minimum corresponding requirements of stenobionts allowed determining the most threatening period of the year for the aquatic ecosystem – summer low water. For a reservoir in the lowland parts of the river, based on the developed method, the calculations substantiate an increase in the minimum volume of environmental flows by 40 % relative to the current one. It is also estimated that the average annual and average second volumes of environmental flows should be about 38 % of the respective river runoff. The obtained results are close to those found on rivers in China, Iran and the United States in the framework of a comprehensive analysis of hydrological, hydraulic and hydrobiological parameters of the aquatic ecosystem