Structural Subsystems Research Articles

TERMINOLOGYOF MANAGEMENT IN THE DISCOURSE SPACE (BASED ON ENGLISH LANGUAGE)

The article is devoted to the study of the English terminological system in the field of management with regard to aspects of the structure and semantics of its components. The typology of cognitive-linguistic and institutional features that distinguish management discourse from other discursive types is explored. A comprehensive analysis of the main ways of forming management terms is carried out, among which morphological derivation, compounding and abbreviation are highlighted. The reasons that determine the dominant role of compounding in management terminology are established. The most frequent morpho-grammatical models in the discursive space of management are identified. Attention is focused on the syntactic status of such terminological units, which allows us to assert that multicomponent terms represent one member of a sentence that does not have synonyms, which fundamentally makes them different from free phrases. Extralinguistic and intralinguistic factors that determine the specifics of the formation of the terminological layer of the lexical system of a language are also explored. Based on the analysis of practical material with its integrative connection to the structural and compositional realities of the modern discursive space of management, the authors of the article propose a comprehensive structural and thematic stratification of terminological units, which allows us to study the conceptual apparatus and trace the main algorithms of the hierarchical interaction of terms of each of the identified structural and thematic segments. Using the continuous sampling method, five structural and thematic groups are identified and stratified, which allows us to conclude that the term management system is a consciously constructed system, divided into flexible and open terminological fields. A statistical analysis is carried out to establish the frequency of use of terminological units of structural and thematic subsystems of the general management terminological system in the discursive space of business. The distinctive feature of abbreviations is investigated, which is represented by a high level of consistency and hierarchy of correlations between abbreviation terms.

Introducing a comprehensive methodology for optimizing the mass of realistic roofing structural systems using cold-formed steel profiles

This study aims to introduce a comprehensive methodology for optimizing complete real structural systems for roofs involving trusses, purlins, and bracing systems jointly, taking into account realistic loads and constraints dictated by technical codes, thereby offering a more accurate representation of practical scenarios. The objective is to achieve the minimum mass through size, shape, and topology optimization of both the main truss and purlin structural subsystems. To achieve this goal, the Enhanced Particle Swarm Optimization (EPSO) algorithm is implemented. An example of a realistic case, which takes into account multiple actual constraints such as stress, displacement, buckling, and natural frequency limits, is thoroughly evaluated. After that, 144 other interactions among dimensions of the building and loads applied are simulated, and the mass of the system is obtained for each one of them. The results indicated that the graphs generated from the various simulations allow for the determination of the optimized mass for different building dimensions. Consequently, the cost and raw material consumption can be estimated for common applications. Therefore, it is concluded that this work presents a significant contribution to structural designers, as the proposed methodology enables structural optimization quickly and easily for practical engineers.

Multimodal active subspace analysis for computing assessment oriented subspaces from neuroimaging data

Background:For successful biomarker discovery, it is essential to develop computational frameworks that summarize high-dimensional neuroimaging data in terms of involved sub-systems of the brain, while also revealing underlying heterogeneous functional and structural changes covarying with specific cognitive and biological traits. However, unsupervised decompositions do not inculcate clinical assessment information, while supervised approaches extract only individual feature importance, thereby impeding qualitative interpretation at the level of subspaces. New Method:We present a novel framework to extract robust multimodal brain subspaces associated with changes in a given cognitive or biological trait. Our approach involves active subspace learning on the gradients of a trained machine learning model followed by clustering to extract and summarize the most salient and consistent subspaces associated with the target variable. Results:Through a rigorous cross-validation procedure on an Alzheimer’s disease (AD) dataset, our framework successfully extracts multimodal subspaces specific to a given clinical assessment (e.g., memory and other cognitive skills), and also retains predictive performance in standard machine learning algorithms. We also show that the salient active subspace directions occur consistently across randomly sub-sampled repetitions of the analysis. Comparison with Existing Method(s):Compared to existing unsupervised decompositions based on principle component analysis, the subspace components in our framework retain higher predictive information. Conclusions:As an important step towards biomarker discovery, our framework not only uncovers AD-related brain regions in the associated brain subspaces, but also enables automated identification of multiple underlying structural and functional sub-systems of the brain that collectively characterize changes in memory and proficiency in cognitive skills related to brain disorders like AD.

Formation of economic freedom and entrepreneurial culture as strategic dominants of enterprise development transparency

Under today's unstable market conditions of business, one of the urgent problems has become the study of economic freedom and entrepreneurial culture as strategic dominants of the transparency of the development of enterprises. This is due to the need to ensure the efficiency of activities and strengthen the competitiveness of Ukrainian enterprises in the European market. This defines economic freedom and entrepreneurial culture as the most priority criteria for the transparency of enterprise development by vector and rank direction. The relationship between economic freedom and entrepreneurial culture as strategic dominants of the transparency of enterprise development was substantiated. The set of structural and logical subsystems of transparency of development, which are interconnected and functioning, taking into account the specifics of their impact on the strategic and analytical support of enterprises, has been studied. The variability of the strategic dominant influence of economic freedom and entrepreneurial culture on the transparency of the development of enterprises was formed using the hierarchy analysis method. The obtained variability allows taking into account the qualitative and quantitative characteristics of the degree of influence of economic freedom and entrepreneurial culture on the general level of transparency of the development of enterprises, which is the basis for the development of strategically oriented areas of their activity

Investigation of statistical energy analysis coupling loss factors of vibro-acoustic systems under thermal environment

Vibro-acoustic systems in aviation engineering could operate in a thermal environment and suffer from high-frequency dynamic excitations. The high-frequency vibro-acoustic problems are commonly solved by the Statistical Energy Analysis method, in which the Coupling Loss Factor is the key parameter for modeling vibro-acoustic systems. This work investigates the CLFs of vibro-acoustic systems under thermal environment. First, based on the modal data considering different thermal effects, the modal CLFs between structural modes and acoustic modes are predicted by the Statistical modal Energy distribution Analysis. Then, the CLFs between the structural subsystem and the acoustic subsystem are calculated. The simulation models employed in this research include the coupled plate-cavity system and the cylindrical shell-cavity system. The influence of thermal effects on the CLFs is discussed. For the investigated cases, in which the boundaries of structural susbsystem are set to simply supported, the results demonstrate that the CLFs decrease with increasing temperature when only the temperature-dependent material properties are considered. However, when only the additional stress stiffness is considered, the CLFs experience a more dramatic decrease compared to when only the temperature-dependent material properties are taken into account. Moreover, when both effects are considered, the influence of the additional stress stiffness has a leading effect on the CLFs. The proposed method can be conveniently applied to various vibro-acoustic systems operating in the thermal environment.

Transient vibration of shafting in coupled hydraulic-mechanical-electrical- structural system for hydropower station during start-up process

The operating parameters of hydroelectric generating system vary constantly in the course of transition, meanwhile, the coupled correlations among hydraulic, mechanical, electrical and structural subsystems are convoluted, which makes the vibration of shafting system prominent, as well as affects the safe and stable operation for hydropower station. In this paper, a coupled hydraulic-mechanical-electrical-structural model for hydroelectric generating system is proposed, while the start-up transient process is incorporated into the investigation system, and the dynamic response from shafting system at different stages attached to start-up process is scrutinized numerically, making allowance for the effect of unbalanced magnetic pull with static and dynamic eccentricity. The kinetic property of structure over the start-up process is illuminated, by means of the comparison with motion trait for system under steady-state operating condition. The results indicate that the dynamic feature of rotor and runner is significantly contrasting in different stages affiliated to the start-up scenario, especially for the voltage building-up subdivision. In addition, the response peculiarity from rotor covering the trajectory, vibration amplitude and frequency components, etc., is markedly altered, due to the participation of static, dynamic eccentricity as well as the matching variation on electromagnetic excitation. The trajectory of rotor evolves from a regular circle to a butterfly-shaped curve, and the associated transient displacement intensifies immensely, besides, the 2x frequency component emerges and corresponding dominant role gradually strengthens, accompanied by a developmental amplitude of 1x frequency in spectrum diagram. Relevant research results can provide profitable reference for the analysis of dynamic characteristic on hydropower station through transient conditions.

A multi-stage, first-order phase transition in LaFe11.8Si1.2: Interplay between the structural, magnetic, and electronic degrees of freedom

Alloys with a first-order magnetic transition are central to solid-state refrigeration technology, sensors and actuators, or spintronic devices. The discontinuous nature of the transition in these materials is a consequence of the coupling between the magnetic, electronic, and structural subsystems, and such transition can, in principle, cross several metastable states, where at one point, the transition takes place within the magnetic subsystem, while at another, the changes occur in the structural or electronic subsystems. To address this issue, we conducted simultaneous measurements of the macroscopic properties—magnetization, temperature change of the sample, longitudinal, and transversal magnetostrictions—to reveal the rich details of the magneto-structural, first-order transition occurring in the prototypical alloy LaFe11.8Si1.2. We found that the transition does not complete in one but in two distinct stages. The presence of the intermediate state changes the potential-energy landscape, which then impacts strongly on the width of the hysteresis associated with the first-order transition. We complement these findings with experiments on the atomistic scale, i.e., x-ray absorption spectroscopy, x-ray magnetic circular dichroism, and Mössbauer spectroscopy, and then combine them with first-principles calculations to reveal the full complexity and two-stage nature of the transition. This new approach can be successfully extended to a large class of advanced magnetic materials that exhibit analogous transformations.

Fragility and vulnerability development of offshore wind turbines under aero-hydro loadings

Wind technology is an effective solution for the carbon neutral over the world. Offshore wind turbines (OWTs) have therefore seen unprecedented development over the decades. Fragility and vulnerability of OWTs are vital in structural performance evaluation and risk assessment of infrastructural systems under natural hazards. Previous research mainly focused on the fragility of OWTs with monopile substructure in the normal operating or parked conditions. In the present study, a realistic situation with respect to the emergency shutdown mode is considered for the OWTs with monopile, tripod, and jacket substructures. A procedure to establish fragility and vulnerability models is developed. Numerical models using a combination of FE software are implemented and validated for dynamic analyses and pushover analyses. Then, the fragility and vulnerability models of the main structural subsystems including rotor, nacelle, tower, and substructure are separately established according to the developed procedure, so as to the fragility and vulnerability models of the whole wind turbine. Besides, impact of operational condition and characteristics of substructure on fragility and vulnerability is comprehensively compared and discussed.

Proposal of a methodology for mass optimization of realistic steel structural systems composed of columns and galleries for support of solid bulk conveyors

Unlike most works in the literature that propose the optimization of benchmark problems or very simple real structures, with idealized loads and restrictions, this work proposes a complete methodology to optimize real support structures of belt conveyor lines, considering realistic loads and restrictions imposed by international technical codes. Thus, the present work proposes a comprehensive methodology to minimize the mass of realistic steel structural systems composed of columns and galleries to support solid bulk conveyors. The objective is to obtain the minimum mass for different interactions between gallery spans and column heights for conveyors, taking into account the optimization of size, shape, and topology of each structural subsystem (columns and galleries) and thus obtaining the mass per unit of length of the conveyor line. For this, recurrent steel support structures are identified, analyzed, and selected according to their performance and, structurally resisting the applied load inputs, they are designed to minimize the structural system mass. The Enhanced Particle Swarm Optimization (EPSO) algorithm is used considering multiple constraints involving stress, displacement, buckling, frequency, and acceleration limits according to various international codes. An example of a realistic conveyor line is presented, in which 42 different interactions among the dimensions of the subsystems are simulated and the minimum mass of the system is obtained for each one of them. Thus, the results obtained allow, from the knowledge of the geometrical characteristics of the span and height of the system, to identify the optimized linear mass for any situation within the study boundary, resulting in an important practical contribution. Additionally, the graphs presented allow the designer to choose optimized solutions in terms of cost and raw material consumption for real-field applications. It was possible to determine that appropriate choices represent up to 35% mass reduction of structural systems.

The European Union's sanctions regime against Russian science

Unprecedented unilateral restrictive measures against Russia's participation in international scientific and technical cooperation (scientific sanctions) have become an integral part of the modern European sanctions policy. The subject of the article is the EU sanctions regime against Russian science, which implements an appropriate policy aimed at ending the participation of Russian scientific institutions and organizations in projects implemented within the framework of EU scientific programs. The purpose of the article is to reveal the content and model of the EU sanctions regime against Russian science. The hypothesis of the study is the position that the model of the sectoral sanctions regime under consideration combines general and specific points. The article argues that the specified sectoral sanctions regime of the EU is autonomous in nature and does not represent something derived from scientific sanctions imposed by member States. General scientific methods of analysis and synthesis, abstraction and generalization were used. This made it possible to move from diverse empirical data to theoretical generalizations about the nature and model of the EU sanctions regime against Russian science. In addition, historical and comparative approaches were used, as well as a modeling method. The article substantiates the conclusion about the contradictory nature of the value and legal foundations of this regime, which is reflected in the lack of unity of views of European expert circles regarding the degree of rupture of scientific ties with Russia. The author substantiates that the massive and, by historical standards, sudden introduction of scientific sanctions in 2022, forming a special sanctions regime, is not the result of certain difficulties that occurred earlier in Russian-European scientific cooperation. On the contrary, it is a systematically motivated destruction of the bridges of scientific diplomacy created after the Cold War. A negative consequence of the functioning of this regime was a decrease in the degree of internationalization of Russian science and its ability to contribute not only to solving applied problems of national socio-economic development, but also to solving global problems of our time. The novelty of the study lies in the fact that for the first time in the scientific literature, structural subsystems of the EU scientific sanctions regime are identified, as well as their additional identification features are characterized.

An efficient method for structural coupling of mechanical systems by using frequency response functions

In many mechanical systems, it is very common to bring together different structural elements or subsystems produced by different producers and create a whole coupled system. It is often not possible to manufacture an entire mechanical system in one place. Although the dynamic properties of each of the subsystems produced by different manufacturers are known, it is a matter that should be known and studied how the dynamic behavior of the new system will be after the creation of a new system by combining these subsystems. In this study, a method for structural coupling of mechanical systems is presented in order to contribute to the solution of structural dynamic problems. It is based on Sherman–Morrison formula known for solving mathematical inverse problems of modified matrices. The method is very useful and practical for real mechanical engineering applications due to only the frequency response functions belong to the coupling coordinates of the subsystems are used. The main highlight of the presented method is there is no need a matrix inversion for calculations.

Dissipation losses limiting first-order phase transition materials in cryogenic caloric cooling: A case study on all-d-metal Ni(-Co)-Mn-Ti Heusler alloys

Ni-Mn-based Heusler alloys, in particular all-d-metal Ni(-Co)-Mn-Ti, are highly promising materials for energy-efficient solid-state refrigeration as large multicaloric effects can be achieved across their magnetostructural martensitic transformation. However, no comprehensive study on the crucially important transition entropy change Δst exists so far for Ni(-Co)-Mn-Ti. Here, we present a systematic study analyzing the composition and temperature dependence of Δst. Our results reveal a substantial structural entropy change contribution of approximately 65 J(kgK)-1, which is compensated at lower temperatures by an increasingly negative entropy change associated with the magnetic subsystem. This leads to compensation temperatures Tcomp of 75 K and 300 K in Ni35Co15Mn50-yTiy and Ni33Co17Mn50-yTiy, respectively, below which the martensitic transformations are arrested. In addition, we simultaneously measured the responses of the magnetic, structural and electronic subsystems to the temperature- and field-induced martensitic transformation near Tcomp, showing an abnormal increase of hysteresis and consequently dissipation energy at cryogenic temperatures. Simultaneous measurements of magnetization and adiabatic temperature change ΔTad in pulsed magnetic fields reveal a change in sign of ΔTad and a substantial positive and irreversible ΔTad up to 15 K at 15 K as a consequence of increased dissipation losses and decreased heat capacity. Most importantly, this phenomenon is universal, it applies to any first-order material with non-negligible hysteresis and any stimulus, effectively limiting the utilization of their caloric effects for gas liquefaction at cryogenic temperatures.

ANALYSIS OF PERFORMANCE COEFFICIENTS IN MAXIMUM ELECTRICAL POWER EXTRACTION FROM STAND-ALONE WIND ENERGY CONVERSION SYSTEM

Increasing performance and improving efficiency in maximum power extraction from Wind Energy Conversion Systems (WECS) is a quite important research topic. Today, in the large-scale WECS, it is widely aimed to extract the maximum mechanical power from the wind turbine using the Maximum Power Point Tracking (MPPT) unit. Similarly, it can also be targeted to achieve maximum mechanical power in small-scale WECS applications. However, losses occur in structural subsystems and electrical subunits located in WECS. Due to these losses, the overall system efficiency decreases and the characteristic of the system is also affected. The operation of these systems can also be performed via maximum electrical output power extraction, which is one of the most up-to-date ideas. Thus, the overall WECS rather than the wind turbine can be optimally controlled. Eventually, maximum electrical power tracking (MEPT) based designs can provide higher power extraction with higher efficiency than MPPT-based ones. In this paper, considering the system operating concepts with MPPT and MEPT for a stand-alone Permanent Magnet Synchronous Generator (PMSG) based WECS, the changes in performance coefficients at defined focus points in terms of system efficiency are evaluated. Technical and theoretical comparative analyzes are also made for each specific wind speed between 8m/s and 12m/s.

Mechanically Improved Zn-Ion Battery Cathodes Based on Branched Aramid Nanofibers

Zinc-ion batteries address common environmental and safety concerns by using nontoxic and abundant metals in conjunction with aqueous electrolytes. Nonetheless, for applications such as structural energy storage, where a multifunctional system aims to replace both the structural and energy storage subsystems of an electric vehicle, safe but mechanically strong components are desired. MnO2, a typical cathode material for Zn-ion batteries, however, exhibits poor mechanical performance. Therefore, a lack of knowledge remains for mechanically strong cathodes for safe, structural Zn-ion batteries. Here, we combine branched aramid nanofibers (BANFs) with MnO2 particles and reduced graphene oxide (rGO) to fabricate mechanically improved cathodes for Zn-ion batteries. The addition of BANFs allows for an increase in the MnO2 loading and significantly improved electrochemical properties (up to 190% increase of capacity). Additionally, hydrogen bonding between BANFs and rGO notably improved the mechanical properties (up to 51% increase in ultimate tensile strength and up to 593% increase in ultimate strain). Electrochemo-mechanical tests were also performed to assess coupling, showing that applied strain decreases the capacity, but no measurable internal stresses develop during electrochemical cycling. This work combines the multifunctionality of structural electrodes with the inherent safety of Zn-ion batteries.

The Arrangement Concept and the Energy Potential of the Vapor Compression Heat and Cooling Supply Based on a Binary Low-Temperature Source

The combined use of low-potential soil heat and air flows in heat pump heat supply systems allows for its regulated redistribution in the processes of customers’ consumption. Herewith, the intensity of energy extraction by the soil heat exchanger decreases, excess heat is accumulated with a decrease in the depth of wells, and the costs of installing and operating probe heat exchangers are also reduced. An improved version of the conceptual arrangement of a vapor compression system for heat and cool supply of buildings based on the integrated heat of soil and ventilation air has been developed. Its distinguished features are the possibility of automatic redistribution of generated heat flows in the subsystems of customers’ heat consumption and accumulation of excess part in the soil mass. When the system is operating in the warm season with the extraction of heat only for hot water supply, there is a more intensive accumulation of excess heat of the ventilation air in the soil mass, which restores its temperature in the accumulation mode for further use with the coming of the heating period. Multifactor analytical dependences of the heat flows of the main equipment have been established, taking into account the initial parameters and operating conditions of the structural subsystems for the extraction, transformation and consumption of heat, which are the basis for determining the energy potential of vapor compression heat and cold supply using a binary low-temperature source.

A built-in self-test and self-adjustment method of MEMS pressure sensor

MEMS device degradation due to aging and other factors is becoming a major concern because it will cause parametric deviations and catastrophic failures in the mechanical and structural subsystems. However, MEMS testing in general which needs specific sophisticated testing equipment is complicated and time-consuming. To solve these problems, this paper specifically introduces a built-in self-test method which based on the periodic observation of the temperature-dependent output signal. A packaging scheme is designed and the test circuit is built to conduct test experiments on MEMS pressure sensors with different ranges and materials. The experimental results show that this method can effectively test the performance and will not affect the continued normal operation of the sensor. Furthermore, some compensation is made to correct the output to greatly improve the accuracy and reliability. Low cost, ease of implementation, and possibility to monitor in real time are the main advantages.

Structural Responses of a Conceptual Microsatellite Structure Incorporating Perforation Patterns to Dynamic Launch Loads

Satellite systems undergo several operational phases during their service life, including the assembly phase, ground transportation phase, the launch phase, and the in-orbit operation phase. Among these phases, the one that imposes the highest level of loadings on the satellite is the launch phase. This phase involves a number of highly dynamic loads, all being imposed upon the satellite simultaneously. Investigation of the responses of the structural subsystem of a satellite to these loadings, namely its maximum deformations and maximum von Mises stresses, is critical if a reasonably high level of confidence is to be achieved. This confidence is in terms of ensuring that no material yielding develops in the structure as a result of the imposed launch loadings. In an earlier work, the structural subsystem of a conceptual microsatellite was designed, employing aluminum 6061 alloy as its material. It was then modified through introducing sets of parametrically defined geometric patterns as perforation patterns to remove material, towards reducing the structure’s total mass, as an alternative to employing composite materials. That effort led to a mass reduction percentage of 23.15%. The current work’s research effort focused on computing the responses of the perforated structure to three of the dynamic launch loads that are imposed upon satellites while being launched, namely quasi-static, random, and shock loads. These responses were then compared to those of the baseline, unperforated, version of the same structure. The values of these loads were taken from the relevant sources, with the values being nominal, and represented the loads that any satellite must qualify for before it can be accepted by the provider for inclusion in a launcher. After imposing these load values upon the structural design it was found that the structural responses indicated that the structure would successfully survive these loads without developing stresses that would lead to material yielding failure. This was deduced from computing the yield margins of safety for each loading case, and all margin values were positive, indicating that the structure, at its current development stage, did have sufficient capacity to withstand these loads without material yielding. This reinforced the conclusion of the earlier work, namely that the perforation concept did have sufficient merit to be further developed towards being implemented in future satellite designs.

General Characteristics of Local Lore Documental Network Resources of the Libraries of Azerbaijan (Based on library collection)

Changing economic conditions, along with the economic development of seperate parts of a country put forward the solution of territorial problems. Therefore, economic zoning as a classic direction of socio-economic geography is becaming current. Azerbaijan has a rich experience in conducting research on scientific and economic zoning. As a result of the accumulation of theoretical basis and experience in carrying out this type of work, there has been a change in the structure of economic zoning: from defining it as a natural-historical whole formation to a territorial production complex, as a non-productive sphere and management, as a socio-economic system based on the territorial unity of people, etc. Consideration of the economic region as a territorial system implies a development in which its individual subsystems and elements have factors and consequences in accordance with their internal laws.
 Economic regions are considered to be complex, hierarchically regulated open systems. They consist of an interconnected combination of multilevel functional and structural subsystems. Here the system and the complex relations are combined for the purpose of general development. Therefore, when studying these territorial entities, it is necessary to use a system-structural approach and take into account the accumulated experience of the complex approach used in economic zoning. At the end of this practice, rich information resources on economic regions are formed, which form the composition of local lore sources. The general issues mentioned in the article are explained in a comprehensive way.

Output feedback model predictive control of spacecrafts based on proportional-integral observer

A novel attitude control algorithm is developed for spacecrafts based on the model predictive control and proportional-integral observer (PIO) in the presence of constraints. The high dimensional nonlinear dynamics are firstly transformed into three single-input single-output linear structural subsystems with coupled actions. Then these actions are viewed as disturbances estimated by the PIOs, and their values are embedded into the models to improve the accuracy of prediction. The predictive controller is composed of the analytical solution and the heuristic constraint handling. In addition, the angular position information is only needed for implementation. Finally, several simulations are used to verify the effectiveness of the developed algorithm. The results show that the designed system compensates the coupled actions well and makes the attitude control performance good.

Chemical long range ordering in all-d-metal Heusler alloys

Chemical ordering in NiMn-based Heusler alloys with magnetostructural phase transition is crucial for understanding the physics of the phase transition. In the new field of all-d-metal Ni(Co)MnTi Heusler alloys, the experimental determination of chemical order is challenging due to the low difference in scattering power of the different elements. Here, we report a combined approach of neutron and x-ray diffraction for an analysis of chemical order in Ni(Co)MnTi alloys and show that no Heusler-typical L21 order between Ti and Mn is present. Furthermore, Co and Ni atoms do not exhibit order among them; however, the phase transition of Co containing samples can be shifted significantly by changing the degree of B2 order with proper heat treatment. Using first-principles calculations, we reveal how the structural and magnetic sub-systems depend on the degree of B2 disorder.