Separate Structural Elements Research Articles

The Structure of the Universe in the Quasar Absorption Spectra

An analysis of the absorption lines observed in the spectra of quasars makes it possible to study the evolution of the structure of the Universe up to redshifts z∼5. The observed clustering of C IV lines demonstrates the multiple birth of low-mass galaxies in separate structural elements—filaments and “pancakes.” This ensures their subsequent regular hierarchical merger in the central galaxy or group of galaxies. Remnants of the early “pancakes” are observed today as the Local Group, groups around the Andromeda and Centaurus galaxies, and other small groups of galaxies. In turn, the observed clustering of Lyman-alpha lines shows that starless dark matter (DM) halos are also formed in structural elements and their hierarchical clustering leads to the formation of massive starless dark matter halos of moderate density, which also appear in numerical models.

Modeling of Dynamic Operation Modes of IVG.1M Reactor

This paper presents the results of a calculation code approach providing a solution to the point kinetics problem for the IVG.1M research reactor of the National Nuclear Center of the Republic of Kazakhstan and allowing the simulation of dynamic processes going on during reactor start-ups, including changes in the thermal state of all its elements, reactor regulator displacement, accumulation of absorbers in the fuel, and the beryllium reflector. A mathematical description of the IVG.1M point kinetics model is presented, which provides a calculation of the reactor neutron parameters, taking into account the dependence of reactivity effects on the temperature, changes in the isotopic composition of materials, and thermal expansion of core structural elements. An array of data values was formed of reactivity added by separate elements of the core when changing their thermal state and other reactor parameters, as well as an array of data with the parameters of heat exchange of coolant-based reactor structural elements. These are used in the process of solving the point kinetics problem to directly replace formal parameters, eliminating the need to calculate the values of these parameters at each calculation step. Preliminary calculations to form an array of values of reactivity effects was applied to the reactor by separate structural elements when their temperature changes were performed using the IVG.1M precision reactor calculation model. The model was validated by the reactor parameters in the critical state. Preliminary calculations to form an array of data with the parameters of heat exchange of coolant-based reactor structural elements were performed in ANSYS Fluent software using the calculation model that describes the IVG.1M reactor fuel element in detail. Validation of the developed calculation code based on the results of two start-ups of the IVG.1M reactor was performed and its applicability for the analysis of transient and emergency modes of reactor operation and evaluation of its safe operation limits was confirmed.

RESEARCH OF OPTIONAL EQUIPMENT SOLUTIONS FOR 3D-PRINTING OF BUILDING PRODUCTS

Raising of problem. Innovative technologies in construction include 3D printing of objects for various purposes. At the heart of 3D printing technology is the principle of layer-by-layer creation of a solid model. This technology is based on the use of construction 3D printers, which are divided into printers that print the entire building and printers that create separate structural elements for the installation of objects. By design, 3D printers are of the flight type (mainly in the form of bridge structures) and with cantilever work equipment in the form of manipulators. Innovative technologies in construction include 3D printing of objects for various purposes. At the heart of 3D printing technology is the principle of layer-by-layer creation of a solid model. This technology is based on the use of construction 3D printers, which are divided into printers that print the entire building and printers that create separate structural elements for the installation of objects. By design, 3D printers are of the flight type (mainly in the form of bridge structures) and with cantilever work equipment in the form of manipulators. Bridge-type printers allow you to get better products due to the precise positioning of the working equipment, especially the extruder, which directly feeds the mixture. In the short time of development of 3D printing in construction (15…16 years) created a large number of different 3D printers of the bridge type, but there is no information on their study and comparative analysis of characteristics, which will improve their design to improve the quality of construction. Purpose. Comparative analysis of the characteristics and performance of variant designs of bridge-type 3D printers. The results of the study. Based on the analysis of printer versions, an advanced 3D printer in the form of a bridge structure with an extruder with two outlets was developed. This can significantly increase the productivity of manufacturing products. Conclusion. Different types of construction bridge-type 3D printers are considered, which have shortcomings and require improvement. An advanced 3D printer design has been developed that allows multiple products to be printed simultaneously. The analysis of the indicators of the considered variants of 3D printers showed that the use of an improved printer will reduce 1,9… 2,7 times the cost of manufacturing 1 m3 of products and 1,8… 2,6 times reduce the metal content compared to other printers.

The System Simulating the State of the Objects and the Process of Their Monitoring with the Help of the Convolutional Neural Network

In this paper, the implementation of the system simulating the states of the objects and the process of their monitoring is considered. The tasks for this system include detection and diagnosis of defective states of the studied objects. In order to configure flexibly the system and to reduce the human factor, the use of neural networks is proposed. The model of the complex for the object monitoring simulation is presented. It is introduced in the form of a software application and is tested as a part of a diagnostic system fitted in the railroad track measuring car. This system makes it possible to determine the dimensions of artificial structures on the railway and, most importantly, to find the sites where the standard overall dimensions are reduced due to the deviation of separate structural elements from their designed position. The algorithmic and mathematical support employed in this paper allows determining the geometric (dimensions and position in space), the kinematic (speed and direction of movement) and the dynamic (motion acceleration, unredeemed car acceleration) characteristics of both moving and stationary objects. During its implementation, such system takes the form of a software and hardware complex equipped with movable and fixed photodetectors, depending on the set of tasks to be solved. A characteristic feature of this study is that the methods and the algorithms it proposes for image processing can be adapted and used in building digital twins of transport infrastructure objects including not only the railway tracks but also various technological and service facilities. Due to this approach, the input of the nodal points of infrastructure objects and their elements can be automated into the project design scheme, exponentially reducing the laboriousness of creating primary models. The aggregation of the proposed methods with the capabilities of modern neural networks improves the primary image processing speed on the side of the client application, without fully occupying the data transfer channel between different modules of the information-measuring complex.

Modeling the destruction of the grain shell of cereal crops

When processing grain cereals, hulling is an important part being the process of destruction of shell and separation of the fruit, from which cereals are prepared, which are a valuable food for people. As a result of theoretical research, a physicomathematical model of grain of cereal crops has been developed as a hulling object consisting of two separate structural elements (spherical shell and spherical kernel), each of which has its own geometric parameters and rheological properties. Mathematical dependences of the destructive stresses of the shell and kernel during static and dynamic interactions with working surfaces on their strength characteristics and geometric parameters are established. The obtained theoretical dependencies, together, represent a mathematical model describing the process of destruction of the grain shell of cereal crops under static and dynamic influences. It can be used to simulate sunflower seed shell hulling in vegetable oil production. The developed model provides quick and qualitative computational experiments with the use of computers and software, with the required set of given values of physical-mechanical and technological properties of the processed grain and structural and technological parameters of machines for destruction and separation of the shell. When using the appropriate software, it is possible to visualize the process of shell destruction with a full frame-by-frame picture of the distribution, magnitude, direction of loads and arising stresses. When using the appropriate software, it is possible to visualize the process of shell destruction with a full frame-by-frame picture of the distribution, magnitude, direction of loads and arising stresses. The possibility of solving this model using computer technology and modern software allows you to significantly reduce the labor intensity of natural experiments, while excluding random and systematic errors associated with the experimental equipment and the researcher.

DEVELOPMENT OF INNOVATIVE INFRASTRUCTURE AS A BASIS OF DIVERSIFICATION PROCESSES OF UKRAINE'S ECONOMY

Introduction. The subject of research is the analysis of forms and features, advantages and disadvantages of economic structure diversification. The relationship between the choice of models for the diversification of traditional or innovative and the creation of innovative infrastructures of the country. Modern conditions, directions, and problems of the innovation infrastructures development in Ukraine are investigated. The current state of innovative infrastructures park development is analyzed. Measures to improve the efficiency of their operation are proposed. The purpose and objectives of the study are to analyze the relationship between the development of innovation infrastructure and the processes of economic diversification and the identification of problems and ways to improve its efficiency. Method (methodology). The systematic approach, methods of analysis and synthesis are applied; the regulatory framework and reporting data of the State Statistics Service of Ukraine were used as an information basis. Results. Recommendations have been developed to ensure favorable conditions for the development and functioning of effective innovation infrastructure. Conclusions. One of the ways to successfully survive in a competitive environment is economic diversification, which forms the country's innovation infrastructure. The creation of innovative infrastructures and their successful development and operation objectively determines the emergence of intensive processes of diversification of the economy of regions and the country as a whole on a qualitatively new basis of innovative high-tech growth, reproduction of various goods and services. These structures give rise to two types of diversification – innovative when the production of innovative goods and services happens, and traditional diversification, which is expressed in a variety of ancillary activities necessary for their proper functioning. To maintain their competitiveness, economic entities must constantly maintain sustainable and efficient forms of economic systems, implement and master the innovations production, modifications, i. e.combine traditional and innovative activities. This is a productive and promising interaction of the processes of traditional and innovative diversification of economic entities in the economic system. However, despite the existence of some elements of the economic diversification system, today, the country lacks a holistic model for the development of effective innovation infrastructure. The existing in Ukraine separate structural elements of the innovation system and the legal field of their functioning are not built into a single innovative economic system, so the results of these elements are isolated and have no synergistic effect. The recommendations provided in the article help to provide favorable conditions for the formation and functioning of the effective innovation infrastructure in Ukraine.

Mathematical Model of a Square Waveguide Polarizer with Diaphragms

The development of new mathematical model for guide polarization converter with diaphragms was carried out in the research by the method of wave matrices. In addition, numerical modeling of the performance of a polarizer with diaphragms is made by simulating the propagation of the fundamental modes with perpendicular linear polarizations. The wave matrix model was obtained by splitting the polarizer into separate structural elements. Each element was described by its own wave transmission matrices. As a result, a general wave scattering matrix was formed. Based on the elements this matrix the electromagnetic characteristics of the considered polarizer were obtained theoretically. In particular, complex reflection and transmission coefficients were calculated. Their modules and phases were analyzed in the frequency interval 10.7-12.8 GHz. To check the correctness of the obtained results an independent numerical simulation was carried out applying the finite element methodology in the frequency interval. The results of both approaches are in good agreement. The engineered converter of polarization with four diaphragms provides a reflection coefficient modulus of less than 0.14 and a transfer coefficient modulus of more than 0.99 for two orthogonal types of polarizations. As a result, a rigorous mathematical method was developed to analyze the elements of the scattering matrix of a waveguide polarizer with diaphragms. It can be used for the development of new broadband waveguide polarizers and waveguide filters based on diaphragm elements.

VERTYBIŲ KOMUNIKACIJOS YPATYBĖS LIETUVOS POLITINIŲ PARLAMENTINIŲ PARTIJŲ PROGRAMOSE (2016 METŲ RINKIMŲ ATVEJIS)

The article discusses the results of value-based communication analysis in the electoral programs of winning parties in Republic of Lithuania Seimas’2016 year election (LVŽS, LSDP, TS-LKD, LRLS, TT, LLRA-KŠS). With the application of three criteria of programs’ analysis – the volume of thematic parts, semantic segments, and ideological values – these questions were addressed: the connection and differences between winner parties’ attitudes towards values; whether traditional parties have preserved ideological identity; what coalitions after the election in the Seimas were possible based on values. The research data revealed that communication of values relevant to society in all analyzed programs is very similar, and, through cluster analysis, the connections between ideological values’ communication were established foremost between traditional parties (first cluster). The second cluster consists of less related programs of other parties. Almost identical results were established when analysing this aspect based on programs’ structural parts. Thus two separate structural elements with stronger (first case) and weaker (second case) interconnections were determined.

The process of nickel nanoparticle formation in hydrophilic polymer/inorganic matrices

Polymer/inorganic hybrid based on silica sol and grafted polyacrylamide chains (SiO2/PAAm) was obtained by radical graft polymerization of acrylamide “from” unmodified silica surface. Its main parameters: RavSiO2, MvPAAm and N (the number of grafts per inorganic particle) were determined using static light scattering, elemental analysis, DTGA and viscometry. The hybrid was used as effective matrix in synthesis of NiNPs by borohydride reduction of Ni2+-ions in aqueous medium. A special approach to characterizing the kinetics and efficiency of NiNPs formation in pure water and hybrid solutions using UV-Vis spectroscopy was proposed and implemented. Due to this, an increase in the rate of accumulation and yield of NiNPs both in pure water and hybrid solutions with an increase in the Ni-salt concentration was established. In addition, a decrease in this rate with an increase in the concentration of hybrid matrices was found, as well as a slowdown in the reduction reaction in hybrid solutions compared to pure water. It was shown by TEM that the separate structural elements of the NiNPs/hybrid compositions are the swollen “hairy-type” hybrid structures with a size of ∼8.0–49.2 nm containing small (∼1.0–5.4 nm) NiNPs in PAAm “coronas.”

Lifetime Prediction for Structural Elements of a Tamman Vacuum High-Temperature Furnace by Means of Mathematical Models

A mathematical structural model of a Tamman vacuum high-temperature electric furnace with a heater in the form of a coal or graphite pipe and thermal insulation in the form of graphite cylinder shields is developed and implemented in the Simulink software package. The thermal resistance of the thermal conductivity of graphite shields, which is traditionally neglected in the calculation of widespread thin metal shields, was taken into account in the simulation of thermal processes. Also, the model takes into account the mass flow of the material of the elements of the furnace structure (the speed of the mass flow depends on the temperature and pressure in the working space), causing a change of the size and, correspondingly, the coefficients of the heat transfer caused by the radiation of the elements of the structure. The temperature regime of separate structural elements (heaters, shields, etc.) is analyzed both for a constant supply voltage of heaters and for the case in which a closed temperature control system is used. The influence of the temperature regime of structural elements on the wear of heating elements and shields is shown.

MATRIX-STRUCTURAL ANALYSIS OF THE STRESS-DEFORMED STATUS OF THE FLEXIBLE INTERFACES AND MEMS COMPONENTS

The designs of modern electronic technology are complex mechanical systems with many rigid bonds, and their microminiature in many cases has reached the physical limit of the dimensional, charge and energy quantization of components. For such mechanical systems, with non-classical methods for mechanics of fastening of separate structural elements, it is difficult to build a design model, simple enough and at the same time one that well reflects physical and dynamic properties. To ensure mechanical strength of interconnects and ultra-thin electronic components, it is necessary to determine the stress-strain state of structural elements. These reasons necessitate the use of numerical methods to calculate the dynamic parameters of the design of electronic equipment interconnections, which will improve the reliability of the developed tools that meet the requirements of regulatory technical documentation on mechanical characteristics, shorten the time and cost of their creation. Subject matter of this work is the study of beam deformation of constant cross section under the action of axial forces, bending moments and torque relative to the longitudinal axis. Goal this work is to determine the deformation of the elements of the structure of the devices using the stiffness matrix with a known vector of external forces. To achieve this goal, it is necessary to solve the following tasks: to consider the existing methods of description and analysis, which take into account the specificity of the structures and technological processes used to manufacture specific structures MEMS; explore the nature of these methods; calculate displacements and deformations using the finite element method; using the stiffness matrix to determine the deformation of the structural elements of the devices; to calculate the deformation of the beam of constant cross-section under the action of axial forces, bending moments and torque relative to the longitudinal axis. Conclusions: stiffness matrix, constructed using functional analysis, allows for the calculation of deformation of MEMS elements and electronic interconnect flexible.

Evaluation of Bridge Project Variants from the LCC Perspective

The lowest purchase price is the easiest criterion in tendering for civil engineering. However, in view of the longevity of these buildings and their social significance, this criterion is insufficient. Renovation and maintenance costs play an important role in the construction life cycle and need to be taken into consideration, too. The structural design clearly influences the operating costs of the building, which can be predicted. The paper presents an example of how to approach this issue. The methodology is focused on bridge structures. The paper presents a software application for the calculation of renovation and maintenance costs which are generated from the following structural elements: abutments, pillars, deck (bearing structure), bearings, bridge deck insulation, drainage, roadway, cornice, railing, crash barriers, expansion joints and noise barriers. The structural elements can be specified in the application in predefined type / material variants. If the user uses material that is not included in the database, this situation is solved by adding the appropriate element to the database. If a combination of materials is used for one component, these materials are defined as separate structural elements. Bridge structures are evaluated over a lifetime of 100 years.

The spectral theory of graphs at researches of fuzzy models of the determined regular structures of network information systems

Operation is devoted the decision of the task increase of structural stability and information efficiency of network information systems on the basis of mathematical apparatus of the theory of fuzzy sets and the spectral theory of graphs. For this purpose introduction of two variants fuzzy structural (channel and nodal) is offered to redundancy of the determined regular topology of network information systems. Functions of an accessory of separate structural elements to which in correspondence the modes of an information exchange which are representing itself as requirements to structural characteristics of system are defined. Analytical and imitative modeling for research of influence fuzzy redundancy on the main structural parameters of the determined topology and estimation of information efficiency of the received structures of network information systems is conducted. Results of modeling showed perspectivity of the offered approach at implementation of structural adaptation of systems to changing conditions of an information exchange.

Базові моделі кінетики деформування-руйнування деревних композиційних матеріалів

Існуючі наразі моделі кінетики деформування і руйнування пов'язані здебільшого з описом переходу з незруйнованого стану матеріалу в зруйнований в одну стадію. Це належить як до класичних теорій міцності, зокрема і кінетичної теорії міцності, так і до теорій і моделей розсіяного накопичення пошкоджень (Continuum Damage Mechanics, CDM). Метою цього дослідження було створення базових моделей кінетики деформування-руйнування (ДР), які описують цей процес у вигляді декількох послідовних переходів окремих структурних елементів (СЕ), у матеріалі, що деформується в часі з одного реологічного стану в інший. Для опису цього процесу залучено апарат формальної кінетики, який дає змогу, знаючи швидкість переходу СЕ з одного реологічного стану в інший, спрогнозувати час досягнення критичної концентрації зруйнованих СЕ. Встановлено, що процес ДР можна розглядати як процес поступового переходу СЕ спочатку пружного стану у в'язкопружний і потім зруйнований. Причому цей перехід може відбуватися як послідовно, так і паралельно. Таким чином, у процесі руйнування постійно змінюється число, а отже, і концентрація СЕ, які перебувають у різних реологічних станах. Зміну концентрації того чи іншого СЕ можна визначити експериментально способом вимірювання величин, що корелюють з параметрами ДР того чи іншого виду деформації тіла. При цьому загальне число елементів структури, що перебувають у різних станах, згідно із законом збереження мас у кожен момент часу ДР має залишатися постійним. Вперше запропоновано двостадійну нелінійну кінетичну модель втрати ресурсу за повзучості композиційних матеріалів на підставі деревини. Застосування методів формальної кінетики під час моделювання фізико-хімічних процесів, які відбуваються під час ДР, дає змогу будувати багатостадійні кінетичні моделі. Застосування методу базових діаграм деформування у поєднанні з двостадійним описом процесу накопичення пошкоджень дає змогу збільшити точність прогнозу допустимого часу за різних схем навантаження під час повзучості.

Architecture of contemporary pedestrian bridges made of fiber-reinforced composite materials

Composite materials are often used in the construction industry nowadays. Including such industries as construction of bridges – unique structures. Today it is possible to produce from FRP not only separate bridge parts and single structural elements, but also entire span structures and one-piece composite bridges made as a monoblock element. The architecture of contemporary footbridges built with the use of fiber reinforced composite plastics in recent decades is being studied and analyzed in the article. The case-study examines the history of plastic composites as structural materials and the trends and evolution of the design of plastic products. The paper proposes a classification of modern pedestrian bridges made of fiber reinforced composites (based on a combination of innovation in the use of materials and in the design). The following three classes are distinguished: composite materials + traditional design; composite and traditional materials + hybrid design; composite materials + new design. The most recent examples of objects belonging to each of the three groups identified in the classification were reviewed and analyzed in course of the study (including contemporary Russian examples of composite pedestrian bridges). Particular attention is paid to the most advanced technologies, such as 3D-printing of composite bridges, as well as a number of other contemporary experimental production methods. The experience of scientists and manufacturers from Germany, Spain, Great Britain, China and other regions of the world has been studied. Further research and application of modern fiber-reinforced composites in combination with the latest production technologies of 3D-printing and computer parametric design can contribute to the development of modern bridge construction, which would be helpful for expanding the typology of structures and improving the design of new structures.

Cracking in heat-releasing perforated material

A model of cracking in fuel isotropic material weakened by a doubly periodic system of cooling cylindrical channels of round cross section is mathematically described. It is assumed that with increasing intensity of the heat in the material its elastic properties become temperature dependent, and nucleation of cracks and failure of the material occur. It is assumed that the zone of cracks nucleation is a finite length layer containing a material with partially broken connections between separate structural elements in plastic flow state at constant stress. The determination of unknown parameters characterizing the initiating crack is reduced to the solution of a singular integral equation. An analysis of the ultimate state of the zone of the weakened interparticle bonds of the material is realized on the basis of the criterion of critical opening of prefracture zone faces.

Некоторые подходы к анализу влияния столичности на развитие и функционирование города

In the article the impact of capitalness on the development and functioning of Yerevan city is analyzed in two dimensions: 1) The impact of capitalness on internal structure of the city, on its main subsystems and on the intensity and nature of interconnection of subsystems of the city, as well as on the change of the role of separate structural elements, 2) Capitals interaction with the external environment, the impact of capitalness on the functioning of communal-territorial systems on different levels, on the main backbone functions of the capital. The changes of the structure of the systems at different phases of development of RA are considered

Invocations and offerings as structural elements in the love spells in Papyri Graecae Magicae

This paper examines the structural elements – namely, the roles of invocation and offerings – in the love spells of the Greek magical papyri. This is achieved through an analysis of spells that invoke a specific named deity in order to see, whether an underlying formal structure uniting this group of spells can be discerned. The meaning of invocation as a structural element is studied through the work of E. Szepes, concerning the magical hymns' origin in and departure from cultic hymns. The roles of invocation, ritual offering, and sleeplessness of the victim can be isolated as separate structural elements, repeated in spell after spell.

Interaction of bridged cracks in a circular disk with mixed boundary conditions

Interaction of arbitrarily located system of rectilinear bridged cracks is considered. It is assumed that the mixed boundary conditions are given on the boundary of the circular disk. It is accepted that the fracture zone is a finite length layer containing a material with partially disturbed bonds between its separate structural elements (end zone). Existence of bonds between the cracks surfaces in the end zones is simulated by application of cohesive forces caused by the presence of bonds to the crack surfaces. Limit equilibrium analysis of cracks is formulated, taking account the criterion of the limit traction of the bonds in the material at the edge of the cracks end zone. DOI: https://dx.doi.org/10.5755/j01.mech.21.5.9518

Crack nucleation in circular disk under mixed boundary conditions

A model of crack nucleation in a circular disk, based on consideration of cracking process zone is suggested. It is assumed that the cracking process zone is a finitelength layer containing a material with partially disturbed bonds between separate structural elements. Existence of bonds between the pre-fracture zone faces (the area of weakened interparticle bonds of the material) is simulated by application of cohesive forces caused by the existence of bonds to pre-fracture area surfaces. Analysis of limit equilibrium of the pre-fracture zone in a circular disk with mixed conditions on the boundary are fulfilled on the basis of ultimate stretching of material’s bonds and includes: 1) setting up the dependence of cohesive forces on opening of pre-fracture area faces, 2) estimation of stress state near the pre-fracture zone with regard to external loads and cohesive forces, 3) determination of dependence of critical external loads on geometrical parameters of the disk, under which the crack appears.