Архів матеріалів науково-періодичні видання ОНТУ (ONUT periodicals achive)

Постійне посилання на фонд

https://card-file.ontu.edu.ua/handle/123456789/9

Переглянути

Зараз показуємо 1 - 20 з 1084

2F-планарні відображення псевдоріманових просторів з f-структурою
(2018) Nadiia Konovenko, Irina Kurbatova, Katya Tsventoukh
Статтю присвячено проблемі дифеоморфізмів многовидів, на яких задано афінорну структуру певного типу. Поняття 2F-планарного відображення афіннозв’язних і ріманових просторів було запроваджено до розгляду Р.Дж.Кадемом. Воно є природним узагальненням F-планарного відображення і містить в собі такі відомі дифеоморфізми афіннозв’язних і ріманових просторів з афінорною структурою, як геодезичні, квазі-геодезичні, голоморфно-проективні відображення. Р.Дж.Кадем досліджував загальні питання теорії 2F-планарних відображень афіннозв’язних і ріманових просторів з афінорною структурою. Зокрема він довів, що таке відображення за необхідністю зберігає афінорну структуру. Курбатова І.М. вивчала 2F-планарні відображення псевдоріманових просторів з афінорною структурою F третього порядку, що задовольняє умовам Коновенко Н.Г. розглядала деякі питання 2F-планарних відображень псевдоріманових просторів з коваріантно сталою f- структурою F, яка визначається співвідношеннями В наявній статті продовжено дослідження 2F-планарних відображень псевдоріманових просторів з f- структурою. Доведено, що псевдорімановий простір з коваріантно сталою f- структурою становить добуток псевдоріманових просторів, один з яких є келеровим; клас псевдоріманових просторів з коваріантно сталою f- структурою замкнений відносно відображень, що розглядуються; за умови коваріантної сталості афінора f-структури 2F-планарні відображення можуть належати одному з трьох типів: повні і канонічні I,II типу; залежно від типу 2F-планарне відображення індукує на компонентах добутку відповідних просторів геодезичне, голоморфно-проективне або афінне відображення. В теорії дифеоморфізмів многовидів відомі потужні класи ріманових просторів, що дозволяють геодезичні відображення, і келерових просторів, що дозволяють голоморфно-проективні відображення зі збереженням комплексної структури. Тому висновки статті дають змогу будувати численні класи псевдоріманових просторів з коваріантно сталою f- структурою та їх 2F-планарні відображення.
A (CHR)3-flat trans-Sasakian manifold
(2019) Koji Matsumoto
In [4] M. Prvanovic considered several curvaturelike tensors defined for Hermitian manifolds. Developing her ideas in [3], we defined in an almost contact Riemannian manifold another new curvaturelike tensor field, which is called a contact holomorphic Riemannian curvature tensor or briefly (CHR)3-curvature tensor. Then, we mainly researched (CHR)3-curvature tensor in a Sasakian manifold. Also we proved, that a conformally (CHR)3-flat Sasakian manifold does not exist. In the present paper, we consider this tensor field in a trans-Sasakian manifold. We calculate the (CHR)3-curvature tensor in a trans-Sasakian manifold. Also, the (CHR)3-Ricci tensor ρ3 and the (CHR)3-scalar curvature τ3 in a trans-Sasakian manifold have been obtained. Moreover, we define the notion of the (CHR)3-flatness in an almost contact Riemannian manifold. Then, we consider this notion in a trans-Sasakian manifold and determine the curvature tensor, the Ricci tensor and the scalar curvature. We proved that a (CHR)3-flat trans-Sasakian manifold is a generalized ɳ-Einstein manifold. Finally, we obtain the expression of the curvature tensor with respect to the Riemannian metric g of a trans-Sasakian manifold, if the latter is (CHR)3-flat.
A calculation of periodic data of surface diffeomorphisms with one saddle orbit.
(2018) Олена В'ячеславівна Ноздрінова, Ольга Віталіївна Починка
In the paper it is proved that any orientable surface admits an orientation-preserving diffeomorphism with one saddle orbit. It distinguishes in principle the considered class of systems from source-sink diffeomorphisms existing only on the sphere. It is shown that diffeomorphisms with one saddle orbit of a positive type on any surface have exactly three node orbits. In addition, all possible types of periodic data for such diffeomorphisms are established. Namely, formulas are found expressing the periods of the sources through the periods of the sink and the saddle.
A dynamical approach to shape
(2022) Martin Shoptrajanov
In this paper we will discuss a dynamical approach to an open problem from shape theory. We will address the problem in compact metric spaces using the notion of Lebesgue number for a covering and the intrinsic approach to strong shape.
A FUNCTIONAL MODEL OF THE INFORMATION TECHNOLOGY FOR MANAGEMENT OF NATURAL EMERGENCY SITUATIONS ON TRUNK ROADS
(2016) N. Fil’
A functional model of the information technology for management of natural emergency situations on trunk roads has been developed on the basis of the IDEF0 notation. The functional model of the information technology for management of natural emergency situations reflects the causal relationships between objects and operations.
A Generalized Palais-Smale Condition in the Fr'{e}chet space setting
(2018) Kaveh Eftekharinasab
The Palais-Smale condition was introduced by Palais and Smale in the mid-sixties and applied to an extension of Morse theory to infinite dimensional Hilbert spaces. Later this condition was extended by Palais for the more general case of real functions over Banach-Finsler manifolds in order to obtain Lusternik-Schnirelman theory in this setting. Despite the importance of Fr'{e}chet spaces, critical point theories have not been developed yet in these spaces.Our aim in this paper is to extend the Palais-Smale condition to the cases of $C^1$-functionals on Fr'{e}chet spaces and Fr'{e}chet-Finsler manifolds of class $C^1$. The difficulty in the Fr'{e}chet setting is the lack of a general solvability theory for differential equations. This restricts us to adapt the deformation results (which are essential tools to locate critical points) as they appear as solutions of Cauchy problems. However, Ekeland proved the result, today is known as Ekleand’s variational principle, concerning the existence of almost-minimums for a wide class of real functions on complete metric spaces. This principle can be used to obtain minimizing Palais-Smale sequences. We use this principle along with the introduced conditions to obtain some customary results concerning the existence of minima in the Fr'{e}chet setting.Recently it has been developed the projective limit techniques to overcome problems (such as solvability theory for differential equations) with Fr'{e}chet spaces. The idea of this approach is to represent a Fr'{e}chet space as the projective limit of Banach spaces. This approach provides solutions for a wide class of differential equations and every Fr'{e}chet space and therefore can be used to obtain deformation results. This method would be the proper framework for further development of critical point theory in the Fr'{e}chet setting.
A metrizable Lawson semitopological semilattice with non-closed partial order
(2020) Taras Banakh, Serhii Bardyla, Alex Ravsky
We construct a metrizable Lawson semitopological semilattice $X$ whose partial order $le_X,={(x,y)in Xtimes X:xy=x}$ is not closed in $Xtimes X$. This resolves a problem posed earlier by the authors.
A new approach to increasing the efficiency of the ship main engine air waste heat recovery cooling system
(2019) R. Radchenko, M. Pyrysunko, M. Bogdanov, Yu. Shcherbak
The efficiency of integrated cooling air at the intake of Turbocharger and Scavenge air at the inlet of working cylinders of the main diesel engine of dry-cargo ship by transforming the waste heat into a cold by an Refrigerant Ejector Chiller (ECh) as the most simple in design and reliable in operation and by complex in design but more efficient Absorption Lithium-Bromide Chiller (ACh) was analyzed. A ship power plant of cogeneration type using the relatively low-grade heat of water of a heat supply system with a temperature of about 90 °C, that significantly complicates the problem of its conversion into cold were considered. Because of the insufficiently high efficiency of transformation of the heat of hot water (low coefficient of performance) as compared with steam, the resulting cooling capacity may not be enough for cooling intake air of the turbocharger and scavenge air, that raises the problem of the rational distribution of heat loads between the Turbocharger Intake Air cooling circuit (subsystem) and Scavenge air cooling circuit and the need to use chillers of various types. This takes into account the rational parameters of cooling processes of the scavenge air in the cogeneration high-temperature stage of scavenge air cooler, in the intermediate stage of traditional cooling air with seawater, and in the low-temperature stage for deep cooling of the scavenge air by using a chiller. A new approach is proposed to improve the efficiency of integrated cooling Intake Air of the turbocharger and Scavenge Air at the inlet of the working cylinders of the ship main engine of a transport ship, which consists in comparing the required cooling capacity and the corresponding heat needs during the trade route with the available heat of exhaust gases and scavenge air of the cogeneration power plant, determining the deficit and excess cooling capacity of heat utilizing cooling machines of various types, that allows to identify and realize the reserves of improving the efficiency of cooling intake air of the turbocharger and the scavenge air of the main diesel engine through the joint use of chillers of various types.
A new curvature-like tensor in an almost contact Riemannian manifold
(2017) Koji Matsumoto
In a M. Prvanović’s paper [5], we can find a new curvature-like tensor in an almost Hermitian manifold.In this paper, we define a new curvature-like tensor, named contact holomorphic Riemannian, briefly (CHR), curvature tensor in an almost contactRiemannian manifold. Then, using this tensor, we mainly research (CHR)-curvature tensor in a Kenmotsu and a Sasakian manifold. We introducethe flatness of a (CHR)-curvature tensor and show that a Kenmotsu anda Sasakian manifold with a flat (CHR)-curvature tensor is flat, see Theorems3.1 and 4.1. Next, we introduce the notion of an (CHR)-n-Einstein inan almost contact Riemannian manifold. In particular, in a Sasakian or aKenmotsu manifold, a (CHR)-n-Einstein manifold is n-Einstein, see Theorem5.3. Finally, from this tensor, we introduce a notion of a (CHR)-spaceform in an almost contact Riemannian manifold. In particular, if a Kenmotsuand a Sasakian manifold are (CHR)-space form, then the (CHR)-curvaturetensor satisfies a special equation, see Theorems 6.2 and 7.1.
A Physics-Based Estimation of Mean Curvature Normal Vector for Triangulated Surfaces
(2019) Sudip Kumar Das, Mirza Cenanovic, Junfeng Zhang
In this note, we derive an approximation for the mean curvature normal vector on vertices of triangulated surface meshes from the Young-Laplace equation and the force balance principle. We then demonstrate that the approximation expression from our physics-based derivation is equivalent to the discrete Laplace-Beltrami operator approach in the literature. This work, in addition to providing an alternative expression to calculate the mean curvature normal vector, can be further extended to other mesh structures, including non-triangular and heterogeneous meshes.
A STUDY INTO ICE BUILD-UP AND MELTING ON VERTICAL COOLED PIPES
(2016) Y. Zasiadko, O. Pylypenko, A. Forsiuk, R. Gryshchenko
The use of cold accumulators based on the principle of ice build up on the cooled surfaces during off-peak periods and ice melting during on-peak periods is an effective method of electricity bills reduction. Within comparatively short periods of on-peak demand a noticeable amount of thermal energy related to ice melting is to be released, it becomes clear that not only sizing of ice accumulators based on balance calculations is actual, but also the determination of time periods of ice accumulation becomes critical. This work presents experimental unit for obtaining data on the ice build-up on the vertical cooled pipes and later on to continuously register data on the ice thickness diminishing at the regimes of ice melting when cooling of pipe stops. The data for ice build-up and melting for some regimes have been presented and analyzed. The data form the base for deriving semi-empirical correlations allowing to determine a time intervals necessary to generate of ice layers of a given thickness.
A survey of homotopy nilpotency and co-nilpotency
(2020) Marek Golasinski
We review known and state some new results on homotopy nilpotency and co-nilpotency of spaces. Next, we take up the systematic study of homotopy nilpotency of homogenous spaces G/K for a Lie group G and its closed subgroup K < G. The homotopy nilpotency of the loop spaces Ω(Gn,m(K)) and Ω(Vn,m(K)) of Grassmann Gn,m(K) and Stiefel Vn,m(K) manifolds for K = R, C, the field of reals or complex numbers and H, the skew R-algebra of quaternions is shown.
A WORD IN DEFENSE OF THE DISCRETE CONTROL SIGNAL
(2017) A. Pavlov
In the structure of automatic regulators are still widely used astatic electrical constant speed actuators. An alternative solution is the use of electrical constant speed actuators, but the proportional action. The comparative evaluation of the both version of the actuators. Attention is drawn to the importance of determine the amount of time the full move electrical actuators. It is argued that the most accurate way to determine this is to use simulation modeling. The advantages obtained in case to ensure proportionality of the action of traditional electric constant speed actuator.
A.K. Bakhtin. Scientific legacy
(2023) Iryna Denega, Yaroslav Zabolotnyi
In the paper we give a brief overview of the O. Bakhtin' scientific results
ABOUT SIGNIFICANCE OF THE CONTROL PROBLEM OF ECOLOGICAL EFFICIENCY OF FUNCTIONING OF TECHNICAL OBJECTS
(2016) S. A. Voinova
It's noted the current stress state of the natural environment due to the increasing harmful effects of the developing global production. It's indicated on the urgency to fully reduce the harmful effects of production. It's shown the control operation TO is highly efficient and productive means of improving the environmental performance of production. It's described the main features of management of ecology, created as well as existing worn out. It's shown the real possibilities of the use of management tools as a highly productive universal environmental funds.
ADJUSTING FLOUR QUALITY BY ENZYMES: CURRENT STATE, PROBLEM ANALYSIS, FUTURE DEVELOPMENT PROSPECTS
(2019) D. Zhygunov, D. Marchenkov, T. Lebedenko
The article overviews the issue of wheat flour modification by enzymes. The role of enzymes in the dough formation process is considered. Modern ways of providing the desired dough parameters for flour products in conditions of Ukraine are shown. Recommendations and suggested directions for further research are given. Flour is a complex multicomponent product and have to correspond with a number of requirements for its composition and properties. Different conditions of grain cultivation and storage result in significant deviations of its quality indicators when it comes to flour mills. The modification of flour going through adding several technological additives, in particular by enzyme products. The action of enzymes to a large extent allows to adjust the properties of the dough and of flour end-products. In addition, enzymes further affect the nutritional values of flour, which makes it possible for the flour production to use low-quality grain, while maintaining the planned quality indicators of flour. The functional properties of flour fractions obtained on different technological passages depend on the content of various anatomical parts of the grain from which they derived from. Particle size, starch damage, protein content, fat content, ash content and intensity of enzyme activity vary significantly depending on the type of grinding equipment. All this gives reason for recommending the introduction of enzymes not while manufacturing bakery end-products but still at the stage of flour production. The damage to the grain with a corn bug, grain germination in Ukraine puts grain-processing plants the task of assessing the activity of own grain enzyme systems. Indirectly, this can be estimated using the gluten deformation index and the grain Falling Number. But the estimation of enzyme systems by such methods does not allow precisely to calculate the amount and composition of enzyme products necessary to achieve maximum effect when adjusting flour properties. The issue of removing anti-nutrient factors in flour, which is largely inhibitors of the action of both their own grain enzyme systems and additionally introduced enzyme preparations, is also relevant.
Advisability use of Arduino controllers in automation of refrigeration devices
(2019) А. Forsiuk, О. Pylypenko, A. Golub, Ya. Zasiadko, V. Voznyy, R. Gryshchenko
The advantages and disadvantages of Arduino controllers in relation to refrigeration automation systems are considered. An example of using the Arduino controller for creating an automation and monitoring system for a non-standard laboratory refrigeration unit is presented. Arduino is a computing hardware platform for affordable design, the main components of which are the microcontroller board with input and output elements, as well as the Processing / Wiring programming environment in a programming language similar to C, C ++. Arduino can be used to create standalone interactive objects, connect to the software that is used on your computer. The main advantage of using Arduino-based controllers is the availability of information about the microcontroller card, the specification of the elements, the software. Information is freely accessible and can be used by developers in any field. Microcontroller boards have a special structure, due to which, if necessary, it can be expanded by adding new components to the device. Thus, the presented platform allows to improve or change the operation of the automation system of the refrigeration unit, depending on the requirements of the consumer of the cold. The presented variant of automation of refrigeration systems gives an opportunity to come up with a new approach to the design of refrigeration units. During the development of the automation system, a modular algorithm for controlling and protecting the refrigeration unit was created in all its variants, the necessary peripheral equipment and signal receivers were selected. It is shown that the value ratio - functionality of these devices significantly exceeds the similar indicators of the world's leading manufacturers of refrigeration automation systems.
AGGREGATED COMPLEXES FOR RICE GRAIN PROCESSING
(2020) V. Petrov, A. Zhdanov, R. Mazej
The paper considers various designs of aggregated complexes for the processing of rice grain. Their technological schemes were built and analyzed, and a breakdown into modules was performed. This allowed us to group the various designs of units and summarize their technological capabilities. The general reduced technological scheme of rice grain processing is considered. The noted variations are as far as practical applications with and without a grain cleaning module. Various schemes of hulling of grain and selection of hulled grain from unlulled are presented. The technological schemes with various hulling machines are analyzed (the Engleberg hulling machine, with rubberized rolls, centrifugal action), which have their own characteristics. The differences in the use of paddy machines and trimers for sorting grain after hulling are considered. The cylindrical trieurs used to select the rice kernel have an original technological scheme (company Yanmar). This allows you to simplify technological communications and make the unit more compact. The units use more compact paddy machines (reduced size, number of tiers, etc.), which, of course, affects their performance. The most common combined machine with a single-pass technological scheme (which was named after the first inventor and manufacturer, a hulling machine from Satake) is considered. In addition to laboratory equipment, centrifugal hulling machines are used in grain processing units, which gives additional advantages (a more compact scheme, due to the combination of several technological operations, hulling, transporting the grain stream, and air separation. For the majority of broken and unbroken grains sieve separators are used for simple circuits. Separators with vertical rotation axis, that allows to transport the rice to a predetermined height. This makes it possible to link this separator, for example with electronic scales.
ALTERNATIVE ENERGY IN THE SYSTEM OF ECONOMIC ECOLOGICAL SAFETY OF THE STATE
(2017) T. Markova
The article deals with economic ecological problems of energy supply of Ukraine, prospects andadvantages of using alternative technologies of heat supply on the base of technologies use of environmentenergy.
AN ARCHITECTURAL APPROACH FOR QUALITY IMPROVING OF ANDROID APPLICATIONS DEVELOPMENT WHICH IMPLEMENTED TO COMMUNICATION APPLICATION FOR MECHATRONICS ROBOT LABORATORY ONAFT
(2017) V. Makarenko, O. Olshevska, Yu. Kornienko
Developing a proper system architecture is a critical factor for the success of the project. After the analysisphase is complete, system design begins. For an effective solution developing it is very important that it will be flexible andscalable. During the system design, its component composition and development tools are determined. The system designphase is an opportunity to maximize the speed and effectiveness of subsequent development.There are quite a lot of architectural approaches for building systems. Despite their small differences, they have much incommon. They all define ways of splitting the application into separate layers. At the same time, in each system, at least, thereis a layer containing the business logic of the application, a layer of data interaction and a layer for displaying data.The "Clean Architecture" approach has been analyzed and adapted to the communication application for mechatronicsrobot laboratory developing. This approach allows to solve all the problems while building the application architecture: itmakes the code modular, tested and easily readable, and also positively affects the quality of development.New architectural components which was introduced by Google in 2017 was considered. The analysis showed that theArchitecture Components fit well into the concept and will interact with the "Clean Architecture" approach. Dagger 2framework was applied for a complete abstraction and simplify testing. Also, it is planned to implement the RxJava library.

Переглянути

Перегляд Архів матеріалів науково-періодичні видання ОНТУ (ONUT periodicals achive) за Назва

Результатів на сторінці

Налаштування сортування