Subsystems Of Structure Research Articles

Vibrations of Periodic Systems Consisting of Identical Subsystems of an Arbitrary Structure

Vibrations of Periodic Systems Consisting of Identical Subsystems of an Arbitrary Structure

Diseño crítico del nanosatélite de la misión FACSAT-2 para la observación y análisis del territorio colombiano

The article presents the critical design of the CubeSat for the FACSAT-2 (SAT-CHIRIBIQUETE) space mission for the georeferenced observation and analysis of the Colombian territory for environmental protection purposes. The satellite provides, through two payloads, data as electro-optical multispectral images (resolution between 4.75 m and 5 m) and, in parallel, data using a spectrometer in the short-wave infrared spectral range of 1000-1700 nm for monitoring greenhouse gases. Based on high-level technical requirements and the operational concept, the input identification and definition of the architecture of the space, ground, and launch segments were performed, defining a six-unit satellite, a ground segment with an S/X-band antenna in the city of Cali, and the use of an EXOpod with launcher-associated characteristics. The subsystems of the mechanical structure, electrical power system, data and command handling system, on-board communication system, and attitude control and determination system were defined and characterized in detail, in accordance with the ECSS standards of the European Space Agency. The initial design solution was customized based on spaces, operational and technical requirements, and the financial budget available for the space mission. It is noteworthy that the article contains exclusive contributions from Colombia, including the definition of the S/X-Band antenna, encryption software, and the design and implementation of the physical interface board to achieve electronic compatibility between the satellite bus and the Argus 2000 spectrometer.

Microwave Switching in the Magnetic and Elastic Subsystems of a Three-Layer Magnetic Structure

Microwave Switching in the Magnetic and Elastic Subsystems of a Three-Layer Magnetic Structure

Microwave switching in the magnetic and elastic subsystems of a three-layer magnetic structure

Three modes of magnetic and elastic vibrations of the layers were revealed when a three-layer planar magnetic structure was excited by a microwave magnetic field. These modes are: microwave switching, low-frequency oscillations, microwave sinusoidal oscillations. Each mode of oscillation of the layers in a certain range of amplitudes of the alternating field is observed depending on the dc magnetic field and the magnetoelastic constant of the layer.

An artificial spring component mode synthesis method for built-up structures

In this paper, we develop a component mode synthesis method that relies on artificial springs to connect the subsystems of a built-up structure. The modal behaviour of the subsystems can be computed using different approaches, from analytical to numerical methods, depending on their complexity. The advantage of using artificial springs to link the subsystems is that one can model them with the Rayleigh–Ritz method, which is problematic in component mode synthesis. As known, the approximating functions must satisfy the system boundary conditions and the use of artificial springs avoids this difficulty. Moreover, and as in other component mode synthesis approaches, one can build reduced-order models at the subsystem level to significantly diminish the dimensions of the entire built-up structure, resulting in substantial reduction of the computational cost when performing numerical simulations. The method is first presented for the simple case of two axially connected beams. Two more complex cases are then addressed. The first one deals with two beams connected at right angles and the second one deals with an internal floor attached to a cylindrical shell, which reminds of some aeronautical structures. The performance of the method is carefully analysed and validated against finite element simulations.

Цифровизация как метод сокращения трансакционных издержек производственного предприятия

The purpose of the study is to present the author's method of digitalization of transactions of solved business tasks to reduce transaction costs of a manufacturing enterprise. The scientific novelty of the research lies in the fact that the elements of digitalization are proposed in the work to reduce the transaction costs of searching for information, negotiating, measuring, and concluding a contract. The introduction of digital technologies into specific business tasks contributes to the optimization of transaction costs in the modern institutional environment. As a result, the information relationship of the structural divisions of the production company was established during the performance of their functions at all stages of the production cycle from procurement to sales, the functional filling subsystems of the organizational structure were determined. Transaction costs, in accordance with their classification, are structured according to these subsystems, they represent the elements of digitalization recommended for use in the business processes of a manufacturing company to reduce its transaction costs. The introduction of digitalization processes of business tasks into the management structure helps to increase the level of validity and speed of decisions in the subsystems of the organizational structure of the company.

ASPECTS OF SUCCESSION URBAN DEVELOPMENT

The modern development of cities is infl uenced by a large number of factors, for example, the political environment, global climate change, and the epidemiological situation. The article examines the relationship between the subsystems of urban structure, ensuring its successive development, with the aspects of sustainable development. Aspects of succession urban development in the context of sustainable development are divided into three groups: environmental, economic and social. The urban planning process consists of short-term and long-term programs. Taking into account the identifi ed aspects, the principles of urban planning are formulated, which are aimed at preserving and developing the successive elements of the architectural and planning structure of the city.

Research and development of comprehensive safety management system for super-tall buildings in Shanghai

In order to meet the requirements of comprehensive safety management of super-tall buildings, a set of integrated safety management system is developed, which can be popularized and demonstrated, including three subsystems of structure, enclosure and firefighting. Interfaces are reserved for water supply and drainage, facilities and equipment, strong and weak electricity and other building safety management subsystems, which can realize the functions of comprehensive safety assessment, safety early warning, Internet of things safety monitoring and data analysis of super-tall buildings. Through the demonstration application in Shanghai Center, it is eventually proved that the system is feasible and effective.

The Creep Model of the Anchorage Structure and the Time-Dependent Reliability Analysis

The anchorage structure is a complex bearing system with undetermined failure modes. According to the component characteristics, we established the segmented diagram for the bearing characteristics and the bearing structure at the anchorage segment. In addition, we described the failure patterns of the subsystems of the anchorage structure and further established the series model for the bolted reinforced system. Moreover, according to the total displacement and the time-dependent deformation characteristics of the bolt, we established a nonlinear creep model to analyze the viso-plastic deformation characteristics of the M-C element. Furthermore, considering the shear strength of the anchored soil, we assumed that the cohesion and the internal friction angle were random variables obeying the Weibull distribution. Using the modified first-order second-moment method (JC method), we obtained the analytic expression of the time-dependent index of the anchorage system. The calculation shows that the variable coefficients of the cohesion and the internal friction angle are exponentially and linearly related to the reliability index, respectively. Simultaneously, the reliability index is exponentially related to time.

Adaptive finite time controller design for switched systems with unknown parameters, mismatched uncertain terms, external disturbances and input perturbations

The main objective of this study concerns with the problem of control and stabilization design schemes for a class of nonlinear switching systems whose dynamics are excited with an undetermined switching logic. Several conditions are taken into account for the subsystems of the whole structure to mimic the natural properties of the real-world nonlinear physical systems. The first is to assume that there is no prior information about the values of the system parameters. The second is to add matched and mismatched uncertain terms to the system dynamics. Furthermore, the effects of the input fluctuations in the actuator model are reflected via gain variations. We assume that the dynamic of a part of the system is uncertain and fully unknown with no control inputs to be relaxed as mismatching uncertainties. And, it is supposed that there is no previous knowledge about the bounds of the lumped uncertainties. To cope the mentioned issues, a robust adaptive control methodology is proposed in this paper. One of the main attributes of the designed control approach is that it guarantees the fast convergence of the system responses to zero with a (practical) finite settling time. A Lyapunov function tactic is then constructed to confirm the theoretic findings of the study. It is also demonstrated that the same controller is applicable for the switched systems perturbed by unknown input saturation nonlinearities. As a result, the chief contributions of this article involve: (1) handling the effects of the system unknown dynamics, external perturbations, unmatched uncertainties, control input variations, unknown parameters and input saturation limiter with no prior information about them and (2) providing a simple effective adaptive algorithm which ensures the fast finite time stability of the entire system under any arbitrary switch schemes. The provided computer simulations highlight the effective performance of the introduced adaptive control technology.

On Two Interacting Markovian Queueing Systems

In this paper, we study a Markovian queuing system consisting of two subsystems of an arbitrary structure. Each subsystem generates a multi-class Markovian arrival process of customers arriving to the other subsystem. We derive the necessary and sufficient conditions for the stationary distribution to be of product form and consider some particular cases of the subsystem interaction for which these conditions can be easily verified.

CHILDREN’S CHORAL ART AS SOCIAL AND CULTURAL PHENOMENON

TheThe article is devoted to the analysis of choral singing at the present stage, taking into account the historical and socio-cultural regularities of the development of musical art. The essence of children’s choral art as a socio-cultural phenomenon is covered. In the article, based on the analysis of theoretical foundations of the research, for the first time the socio-cultural potential and the importance of choral art in the life of society are highlighted. Achievements and perspectives of choral experience and choral practices are considered in order to create a decent environment for the current state of children’s choral art in Ukraine. Existing research represents a great pedagogical heritage and is a significant factor in establishing a methodological base for music and pedagogical repertoire. In order to clarify and fill in the specific content of various aspects of the concept of children’s choral art in the socio-cultural space, it is necessary to turn to the review of problems of personality education based on cultural traditions, which are considered in the works of V. Andrushchenko, A. Boyko, O. Bondarevskaya, V. Kushnev, O. Novikova, A. Shcherbakova and others. The analysis of the problem of choral education in the history of music education in Ukraine gives every reason to say that it is through the means of choral music that a child’s personality should be developed, since it preserves all educational opportunities. The modern system of education takes into account the requirements of a society belonging to the European civilization and realizes ethical and aesthetic education, forms a high humanistic culture of personality, capable of counteracting manifestations of spirituality. Studying children’s choral performance in the socio-cultural space, first of all it is necessary to distinguish its components as the phenomena of the aesthetic, as one of the most important components of the contemporary artistic space. However, performance (like any other artistic phenomenon), being a phenomenon not only aesthetically pleasing, but also fully socially dependent on other subsystems of the social structure. One of them is the scale of the social phenomenon under consideration. The second is positioning, which collectively determines the sufficiently high degree of influence of choral music on children as a modern social phenomenon on the set of related, or more precisely, connected with it other socio-cultural phenomena and processes. The ways of their development should be sought in the expansion of international creative contacts in all forms: festivals, competitions, concerts, workshops, etc. Both of these positions are projected on the need to consider the process of functioning of choral music in the modern socio-cultural space, taking into account its own diversity.

Numerical model of the Baltic Sea circulation

The problem of numerical simulation of the Baltic Sea large-scale circulation is considered. The Baltic Sea numerical model is based on the two previous models: the model of ocean dynamics developed at the Institute of Numerical Mathematics of the RAS and the FRESCO model of marine hydroecosystem developed at the Estonian Marine Institute, University of Tartu. The model is based on primitive equations written in spherical ? coordinates with a free surface in the hydrostatic and Boussinesq approximations. The structure of numerical algorithm is described. The algorithm is based on the method of multicomponent splitting and includes splitting by physical processes and spatial coordinates. The equations of sea dynamics are written in a symmetrized form. The problem is split into several energetically balanced subsystems (splitting by physical processes). Each subsystem can be additionally split into subsystems of a simpler structure (splitting by spatial coordinates). The numerical experiment consists in the calculation of the Baltic Sea hydrodynamic fields with the spatial horizontal resolution of ~3.5 km and 25 vertical ?-levels nonuniformly distributed over the depth. The atmospheric forcing is calculated according to the Era-Interim data, the calculation period is 2 years: 2007 and 2008. The results of numerical simulation demonstrate good resemblance to observation data, as well as the results of the Baltic Sea dynamics computation obtained from other models.

Ferroelectricity in systems of induced and permanent dipoles: A Monte Carlo study

Dielectric and ferroelectric properties in systems of permanent and induced dipoles are calculated with a Monte Carlo method, the importance-sampling method. The systems are dipole chains and dipole planes, which can be looked at as subsystems of a perovskite structure. Depending on the system and the parameters we find spontaneous polarizations, ferroelectric domains, temperature-dependent hysteresis loops of the polarization, and a Curie–Weiss law for the susceptibility. These properties are mainly due to the cooperation of induced and permanent dipoles. The most difficult problem is the calculation of the spontaneous polarization, i.e., the calculation of the polarization without an applied field. In this case, a high iteration number is required.

Medium-transferability and presentation structure in speech and writing

Lyons' notion of medium-transferability suggests that there are units of the abstract language system that are medium-independent, e.g. clause, phrase and word. But there are also medium-dependent linguistic choices which are used by the language user to present his or her message: (1) In the case of speaking there is phonic presentation of encoder in terms of intonation and the allomorphs of connected speech. (2) In the case of listening and transcribing there is graphic presentation of decoder-encoder with no high degree of standardisation. (3) In the case of writing there is graphic presentation of encoder according to the highly standardised rules of orthography and punctuation, which may function as metalingual statements. (4) In the case of reading there is phonic presentation of decoder-encoder, again in terms of intonation and the allomorphs of connected speech. This kind of presentation structure is not unique but can vary according to the number of readers and to the quality of their performance. Quite generally, the contribution of the various subsystems of presentation structure to linguistic analysis is often not seen in a systematic way. Therefore, this article argues for a general framework for presentation structures.

Solution of large nonlinear engineering systems through subsystems

The ability to break a large system into physically realizable subsystems can greatly simplify both the modelling and computer algorithm aspects for the analyst. Common procedures to solve nonlinear systems, where the Newton-Raphson method is applied directly to a formulated set of system equations, do not easily suggest a way to do this. In this paper we present a simple method to solve nonlinear problems through subsystems founded on well-established graph-theoretical methods. The key to the approach is to address the nonlinear problem at the component level, before the system equations are formulated. The approach is attractive since it permits the formulation methods of linear systems but retains all of the properties of the Newton-Raphson method. Iterations are carried out in a hierarchical manner by alternating between individual subsystems and the assembled subsystems. Furthermore, with the introduction of symbolic programming systems such as MAPLE, many avenues open up to simplify greatly the model building of nonlinear problems, especially when the system contains subsystems of a similar structure. © 1997 Elsevier Science Limited

Use of Statistical Energy Analysis for Rotating Machinery, Part I: Determination of Dissipation and Coupling Loss Factors Using Energy Ratios

A method for determining the dissipation and coupling loss factors of a fully assembled machinery structure is presented in this paper. The method is based on the experimental measurements of the total loss factors and the energy ratios between the subsystems of the machine structure when fully assembled. The presented approach, which will be referred to as the energy ratio method, is suitable for both conservative (no energy dissipation at the junction) and non-conservative coupling. Not only does this energy ratio method determine the coupling loss factors for directly coupled subsystems, but it also determines the coupling loss factors between subsystems which are not directly coupled. This type of coupling exists when the subsystems of the structure are small compared to the wavelength of vibration and all coupling interfaces are in the near field of each other. A series of experiments are carried out to demonstrate the use of this approach and to verify the accuracy of this method for predicting the energy distribution among a set of coupled subsystems. The determined coupling and dissipation loss factors are used in a Statistical Energy Analysis (SEA) model of a rotating machinery component and the estimated results for the response are compared to the directly measured results. As expected, the agreement between the SEA estimated results and the directly measured results is good.

On the cutting stability of the lathe under different working conditions

To study the cutting stability of a lathe, this paper presents an experimental investigation of the limit cutting depth and the corresponding chatter frequencies of the lathe under different working conditions. Test results show that the limit cutting depths and the corresponding chatter frequencies of the same lathe will be quite different, as the cutting diameter and cutting position of the workpiece change, and the limit cutting depth will also be changed with the cutting speed and feed rate at the same chatter frequency. Test results also show that natural vibration or vibrations may occur in a sub-system or sub-systems of the lathe structure separately or simultaneously under appropriate conditions, thus leaving chatter marks on the machined surface that correspond to single frequency vibrations or multifrequency vibrations. The current standards for dynamic acceptance tests of the lathe specify that the workpiece diameter d 1 should be one quarter times the swing of the lathe. Actually this is good only for checking the dynamic behavior of the spindle-workpiece-tailstock sub-system and not for the lathe as a whole. The paper suggests that a testpiece twice as big ( d 2 = 1/2 D) should also be used to check the dynamic behavior of the bed-carriage sub-system.

Transformations in a metal/insulator/semiconductor structure with an amorphous insulator film caused by contacts

The thermodynamic criteria for and structural consequences of interphase interactions at the boundaries of adjacent layers in an Nb/a-Nb 2O 5/MnO 2 (where a indicates amorphous) metal/insulator/semiconductor (MIS) structure were analysed and studied as an example of the behaviour of similar MIS structures. It was shown experimentally that the interaction in the thin insulator film induced a permanent electrochemical breakdown of the MIS structure which was followed by a step-like electrothermal breakdown under certain conditions. The relation between transformations in the ionic and electronic subsystems of the MIS structure at both stages of its relaxation into a state of thermodynamic equilibrium was investigated. A mechanism was proposed for the electroforming of the film, and investigations of the current-controlled negative resistance and bistable memory switching were performed.

The Orbiting Geophysical Observatories

The Orbiting Geophysical Observatories are systems designed to fulfill a primary objective of conducting large numbers of significant, diversified experiments for making scientific and technological measurements within the earth's atmosphere, the magnetosphere, and cislunar space to obtain a better understanding of earth-sun relationships and the earth as a planet. Configured to meet scientific requirements, the observatories include six appendages of different lengths for experiments requiring locations at a distance from the main body. Five degrees of freedom allow the capability of continuously orienting solar and antisolar, geocentric and antigeocentric, and orbital experiments within relatively close limits. Designed to include five basic subsystems of structure, stabilization and control, power, communications and data handling, and thermal control, the observatories have well-defined interfaces for experiments. Five of the six observatories in the program have already been launched and have returned significant scientific information. The last observatory is scheduled for launch in Spring 1969. Weights of the observatories range from 1073 to 1400 lb, including as many as 390 lb of experiments. One hundred six experiments have already been orbited on the five spacecraft, with 26 experiments scheduled for the last mission. Orbits have included three highly eccentric orbits inclined initially approximately 31° and two low-altitude nearly circular polar orbits. The orbit for the last mission, OGO-F, is of the latter type.