Diagram Of System Research Articles

Экономическая эффективность применения систем мониторинга крутильных колебаний на судах

A torsional vibration monitoring system is being investigated, and an assessment of the economic efficiency of its implementation on ships is made. A schematic diagram of the torsional vibration monitoring system is illustrated and a photograph of an experimental sample of the monitoring system is provided. An assessment of the economic efficiency of the implementation of torsional vibration monitoring systems on ships is being carried out to prevent the occurrence of emergency situations with marine propulsion systems. The rules of classification societies, scientific and technical literature in the field of torsional oscillations and industrial economics, and the authors' own research were used as materials. The methods used are analysis and computational experiment. Data on the economic costs of the shipowner in the event of emergency situations in case of fatigue failures of elements of ship's engine and propulsion systems were obtained. An assessment of the costs for the development, installation and maintenance of a torsional vibration monitoring system on ships was made; as well as an approximate assessment of the volume of the Russian domestic market for installation and maintenance of torsional vibration monitoring systems on ships. It is noted that the cost of the consequences of propeller shaft failures ranges from several million to tens of millions of rubles. It is concluded that the development and implementation of torsional vibration monitoring systems will reduce the cost of the shipowner for a routine assessment of the technical condition of torsional vibration dampers and reduce the risks of costly accidents with shipboard engine complexes.

Spectroscopic and Computational Study of ZnCl2-Methanol Low-Melting-Temperature Mixtures.

Alcoholic electrolyte mixtures have wide applications in industries. In this study, a series of mixtures composed of ZnCl2 and methanol (MeOH) with ZnCl2 mol % from 6.7 to 25 were prepared, and their spectral, structural, and thermodynamic properties were studied using infrared (IR) spectroscopy, differential scanning calorimetry (DSC), and density functional theory (DFT) calculations. The DFT-assisted analysis of excess spectra, supported by 2D-correlation spectroscopy, led to the identification of the major constituents of ZnCl2-MeOH mixtures, namely, MeOH monomer, MeOH dimer, and ZnCl2-3MeOH complex, produced after dissociation of MeOH trimer which represents the bulk methanol. The Hirshfeld charge analysis showed that in the competition between the O-H···Cl hydrogen bond (H-bond) and Zn ← O coordination bond to transfer charge in ZnCl2-MeOH complexes, the latter always dominates, making MeOH positively charged. The phase diagram of the binary system showed the presence of V-shaped glass transition temperatures (Tg), characteristic of low-melting mixture solvents (LoMMSs). The present study provides insights into the microscopic properties of the system and sheds light on the understanding of the general principles to prepare deep-eutectic solvents (DESs) or LoMMSs using inorganic salts and alcoholic compounds.

Eutectic Resolves Lysolipid Paradox in Thermoresponsive Liposomes.

A better molecular understanding of the temperature-triggered drug release from lysolipid-based thermosensitive liposomes (LTSLs) is needed to overcome the recent setbacks in developing this important drug delivery system. Enhanced drug release was previously rationalized in terms of detergent-like effects of the lysolipid monostearyl lysophosphatidylcholine (MSPC), stabilizing local membrane defects upon LTSL lipid melting. This is highly surprising and here referred to as the 'lysolipid paradox,' because detergents usually induce the opposite effect─they cause leakage upon freezing, not melting. Here, we aim at better answers to (i) why lysolipid does not compromise drug retention upon storage of LTSLs in the gel phase, (ii) how lysolipids can enhance drug release from LTSLs upon lipid melting, and (iii) why LTSLs typically anneal after some time so that not all drug gets released. To this end, we studied the phase transitions of mixtures of dipalmitoylphosphatidylcholine (DPPC) and MSPC by a combination of differential scanning and pressure perturbation calorimetry and identified the phase structures with small- and wide-angle X-ray scattering (SAXS and WAXS). The key result is that LTSLs, which contain the standard amount of 10 mol % MSPC, are at a eutectic point when they release their cargo upon melting at about 41 °C. The eutectic present below 41 °C consists of a MSPC-depleted gel phase as well as small domains of a hydrocarbon chain interdigitated gel phase containing some 30 mol % MSPC. In these interdigitated domains, the lysolipid is stored safely without compromising membrane integrity. At the eutectic temperature, both the MSPC-depleted bilayer and interdigitated MSPC-rich domains melt at once to fluid bilayers, respectively. Intact, fluid membranes tolerate much less MSPC than interdigitated domains─where the latter have melted, the high local MSPC content causes transient pores. These pores allow for fast drug release. However, these pores disappear, and the membrane seals again as the MSPC distributes more evenly over the membrane so that its local concentration decreases below the pore-stabilizing threshold. We provide a pseudobinary phase diagram of the DPPC-MSPC system and structural and volumetric data for the interdigitated phase.

Stability and modal evolution characteristics of pipe-in-pipe system with internal intermediate support

In this paper, the stability of the pipe-in-pipe (PIP) conveying fluid system with intermediate supports are studied. The focus of the study is mainly on the influence of the intermediate supports on the critical velocity boundary. The governing equations of the coupled system are established according to Hamilton’s principle, and the modal functions in analytical solution form and the frequency equation in implicit function form are obtained by using the Laplace transform technique. In the numerical discussion part, the influence of the stiffness and position of the support on frequencies, modal functions, and critical flow velocity of the system is discussed. In the stability region diagrams of the cantilever PIP system, it is found that when the position and stiffness of the support change, the minimum critical flow velocity is frequently converted between different modes, and there are two different types of critical flow velocity conversion phenomena (CFVC). And high-order flutter instability, ‘jump’ phenomenon, S-shaped critical velocity boundary and modal conversion phenomenon are discussed in detail. In addition, the effective and negative regions of the support in the cantilever PIP and simply supported PIP systems are given.

Reconstructing bifurcation diagrams of chaotic circuits with reservoir computing.

Model-free reconstruction of bifurcation diagrams of Chua's circuits using the technique of parameter-aware reservoir computing is investigated. We demonstrate that (1) reservoir computer can be utilized as a noise filter to restore the system dynamics from noisy signals; (2) for a single Chua circuit, a machine trained by the noisy time series measured at several sampling states is capable of reconstructing the whole bifurcation diagram of the circuit with a high precision; and (3) for two coupled chaotic Chua circuits with mismatched parameters, the machine trained by the noisy time series measured at several coupling strengths is able to anticipate the variation of the synchronization degree of the coupled circuits with respect to the coupling strength over a wide range. Our studies verify the capability of the technique of parameter-aware reservoir computing in learning the dynamics of chaotic circuits from noisy signals, signifying the potential application of this technique in reconstructing the bifurcation diagram of real-world chaotic systems.

Flipping the Political Scale

This article investigates spatial representations of the political system in Swedish civics textbooks, 1900–2020. It challenges common assumptions about the spatiality of politics, such as the analogy between parties representing the upper classes and the right. Instead, the investigation reveals a complicated history, which includes a sudden shift in polarity of the political spectrum in the 1980s. Then, the political right finally moved to the spatial right in diagrams of the political system, after having been placed to the left for most of the 20th century. The article also discusses how diagrammatic representations of the party system changed in the 2010s, as democracy was perceived to be under threat and new dimensions emerged in politics. These puzzling empirical findings are analyzed with the help of theories on spatial and diagrammatic cognition, such as primary metaphors and spatial agency bias.

Highly efficient separation and equilibrium recovery of H2/CO2 in hydrate-based pre-combustion CO2 capture

Gas hydrate-based CO2 capture processes have attracted considerable attention due to their potentials for energy-efficient pre-combustion CO2 capture. Recent investigations have explored the use of tailored-wettability porous silica gels, highlighting benefits in thermodynamic and kinetic efficiencies, specifically characterized by low energy requirements and rapid formation. However, achieving high purity levels for both H2 and CO2 is crucial for practical implementation. Consequently, identifying and optimizing an effective separation route becomes imperative. In this study, we examined the thermodynamic stability, gas uptake, and separation factors of THF (5.56 mol%) + H2 + CO2 hydrates with varying compositions (H2:CO2 = 80:20, 60:40, 30:70, or 20:80 mol%) in C0 and C1 silica gel (functionalized by monofunctional alkylsilanes (X-(CH3)2-Si-Cn)) systems with SDS (0 or 500 ppm). Pressure-composition diagrams for THF + H2 + CO2 systems in C0 and C1 silica gel were meticulously measured. Notably, the C1 silica gel system without SDS demonstrated good thermodynamic stability, substantial gas uptake, and a significant separation factor. Based on the pressure-composition diagram of the C1 silica gel system, we proposed a highly efficient route for separating H2 and CO2. This proposed cyclic process involves a three-stage reactor and achieve to gas hydrate-based pre-combustion CO2 capture, yielding a purity of approximately 91 % H2 and 94 % CO2. The present findings provide valuable insights into optimizing the wettability of porous media and efficient separation routes, demonstrating the feasibility of a gas hydrate-based pre-combustion carbon dioxide capture process.

Business Model to the LASSE performance at Microgrid environment

The Microgrid (MG) scenario has a socioeconomic and technical character seeking to promote the sustainable, technological and economic advance. Through the MG, the consumer may set up its own business with a the sale of its own energy, thus, the Automation and Electrical Systems Simulation Laboratory (LASSE) is interested in participating of the MG market. Creating and/or innovating a business requires knowledge of the application environment. This reality has as consequence the determination of strategies for the company’s management in the vision of the market dynamics. This research aims to define the necessary requirements for the performance of LASSE in the MG environment and to develop the systemic LASSE diagram associating the structural elements of the business model with the characteristics of LASSE. The information was generated through the Business Model Generation (BMG) methodology, among which the Business Model Canvas tools stand out. The research interests LASSE for creating ideological guidelines for members of the LASSE Smart Energy Project. In this way, it is possible to clearly understand the process of introduction to the MG environment, as well as the necessary characteristics for the elaboration of Business Models (BM).

On developing structural and technical solutions to ensure the vibratory displacement of the working medium

A research study into using vibration technologies for the transport of granular working medium was carried out. A vibration testing machine, whose calculation model includes a mechanical vibration system having two degrees of freedom with a rigid body on elastic supports, was selected as an object of research. The study involved analysing the variation in the system vibrations by using the structural theory for vibration isolation systems, where a dynamic equivalent represented by a structural diagram of an automatic control system is compared to the initial calculation model. The structural diagram of the system is based on the motion equations in operator form obtained using Lagrange differential equations of the second kind. The Laplace transform was used to transform the initial data for the system of differential motion equations. The paper addresses the characteristics of a new structural and technical solution in the field of vibratory displacement of a granular working medium using the working body of a vibration technological machine, which involves introducing a number of additional weights, levers, springs, and hinges. Here, springs comprise generalised structures containing both elastic elements and vibration dampers. To connect the coordinates of the endpoints in the working body of the vibration technological machine, analytical relations were obtained. It was established that varying the parameters of the elements within the elastic-lever blocks allows the dynamic state of the vibration technological machine to be controlled. In addition, it was shown that the obtained structural diagram helps to derive mathematical expressions for transfer functions, comprising the ratio between the motion coordinates of a technical object and an external force disturbance. On the basis of these expressions, the transfer function for the ratio of the motion coordinates of the vibration technological machine was formulated. A mathematical model of a vibration technological machine was obtained in the form of a transfer function, including a large number of additional elastic and massinertial elements, where the parameters of vibration displacement can be adjusted automatically. The research results will allow the existing technical solutions in the field of technological engineering to be modernised.

Corrosion Behavior of X80 Steel in a Simulated Soil Solution Under Square-Wave Current Interference

The buried pipeline is disturbed by the dynamic direct current (DC) stray current with the subway as the main leakage source, which has the safety risk of accelerating corrosion, resulting in pipeline failure, which not only causes economic losses but also threatens personal safety. Therefore, it is necessary to study the corrosion behavior of pipeline steel under dynamic DC interference. The corrosion behavior of X80 steel under dynamic DC interference were studied by a mass loss test, alternating current impedance, circuit simulation, x-ray diffraction, and a Pourbaix diagram. Combined with the corrosion efficiency and Pourbaix diagram of the Fe-H2O system, the reversible process and reduction process mechanism in the Faraday process are proposed. The reason why the corrosion efficiency slows down in the process of non-Faraday is analyzed by the electric double-layer model of equivalent circuit calculation. In addition, based on the above corrosion process, the corresponding conceptual model of the corrosion mechanism is proposed. The experimental results show that with the asymmetry of positive and negative half-cycle interference duration and the increase of current density, the corrosion efficiency, and current corrosion efficiency of X80 steel decrease, and local corrosion intensifies. The length of the negative half-cycle interference affects the capacitive charge-discharge effect at the metal/solution interface and the reduction reaction process of corrosion products, resulting in corrosion slowing down and corrosion efficiency reduction. This is also an important reason for the reduction of corrosion mass loss observed in the experiment compared with steady-state DC.

Probing holographic flat bands at finite density

Flat band electronic systems exhibit a rich landscape of correlation-driven phases, both at the charge neutrality and finite electronic density, featuring exotic electromagnetic and thermodynamic responses. Motivated by these developments, in this paper, we explicitly include the effects of the chemical potential in a holographic model featuring approximately flat bands. In particular, we explore the phase diagram of this holographic flat band system as a function of the chemical potential. We find that at low temperatures and densities, the system features a nematic phase, transitioning into the Lifshitz phase as the chemical potential or temperature increases. To further characterize the ensuing phases, we investigate the optical conductivity and find that this observable shows strong anisotropies in the nematic phase.

Ambient melting behavior of stoichiometric uranium oxides

As UO2 is easily oxidized during the nuclear fuel cycle it is important to have a detailed understanding of the structures and properties of the oxidation products. Experimental work over the years has revealed many stable uranium oxides including UO2, U4O9 (UO2.25), U3O7 (UO2.33), U2O5 (UO2.5), U3O8 (UO2.67), and UO3, all with a number of different polymorphs. These oxides are broadly split into two categories, fluorite-based structures with stoichiometries in the range of UO2 to UO2.5 and less dense layered-type structures with stoichiometries in the range of UO2.5 to UO3. While UO2 is well characterized, both experimentally and computationally, there is a paucity of data concerning higher stoichiometry oxides in the literature. In this work we determine the ambient melting points of all the six stoichiometric uranium oxides listed above and compare them to the available experimental and/or theoretical data. We demonstrate that a family of the six ambient melting points map out a solid-liquid transition boundary consistent with the high-temperature portion of the phase diagram of uranium-oxygen system suggested by Babelot et al.

Study on the solid-liquid equilibrium and thermodynamic model of the L-phenylalanine + L-tryptophan + water system.

Amino acids hold significant importance in the diagnosis and treatment of various chronic diseases. Accurate solid-liquid equilibrium data are the key to drug synthesis and chemical production. However, the studies on the solid-liquid equilibrium of amino acids remain limited. In this work, the solid-liquid equilibrium of the L-tryptophan + L-phenylalanine + water ternary system under atmospheric pressure at temperatures of 278.15 K-318.15 K was explored via isothermal solution saturation. The isothermal equilibrium phase diagram of the ternary system was constructed. The obtained solid-liquid equilibrium data were correlated with a semi-empirical-model, yielding thermodynamic parameters pa, pb, pc, and k. Furthermore, the model can be used to effectively predict the solid-liquid equilibrium data of ternary systems at other temperatures, and the dY and dP are 0.005 and 4.34%, respectively. The solid-liquid equilibrium data and ternary equilibrium phase diagrams of the system were utilized for the separation and purification of an L-tryptophan and L-phenylalanine mixture. By employing thermodynamic models to calculate the relevant phase diagram data for mixtures with different proportions, effective separation and purification of the mixture could be achieved using the principles of variable temperature phase diagrams. These works are valuable for optimizing chemical processes and have practical implications in the field.

Automatic Generation of Topology Diagrams for Strongly-Meshed Power Transmission Systems

Topology diagrams are widely seen in power system applications, but their automatic generation is often easier said than done. When facing power transmission systems with strongly-meshed structures, existing approaches can hardly produce topology diagrams catering to the aesthetics of readers. This paper proposes an integrated framework for generating aesthetically-pleasing topology diagrams for power transmission systems. Input with a rough layout, the framework first conducts visibility region analysis to reduce line crossings and then solves a mixed-integer linear programming problem to optimize the arrangement of nodes. Given that the complexity of both modules is pretty high, simplification heuristics are also proposed to enhance the efficiency of the framework. Case studies on several power transmission systems containing up to 2,046 nodes demonstrate the capability of the proposed framework in generating topology diagrams conforming to aesthetic criteria in the power system community. Compared with the widespread force-directed algorithm, the proposed framework can preserve the relative positions of nodes in the original layout to a great extent, which significantly contributes to the identification of electrical elements on the diagrams. Meanwhile, the time consumption is acceptable for practical applications.

ПОШУК МЕЖ ПРЕДСТАВЛЕННЯ ВНУТРІШНІХ ЗБУРЕНЬ АКТИВНОЇ ЗОНИ ВВЕР-1000 У ВИГЛЯДІ ФІЗИКО-МАТЕМАТИЧНОЇ ТА АПРОКСИМАЦІЙНОЇ МОДЕЛЕЙ

Abstract. The scientific article is devoted to the study of the use of physical-mathematical and approximation models for simulation of the power change control system at nuclear power plants with VVER-1000. Methods for controlling energy release have been studied, problem of optimal reactor control has been solved, and block diagram of the automatic control system has been developed. The limits of using models to ensure the stability of control processes are clarified. Keywords: Automatic control system, control programs, reactor power, boundaries search, pressurized water reactor.

Methodological features of the development of intelligent information technology for the transportation process in railway transport

The article presents methodological features of the development of intelligent information technology (hereinafter referred to as IIT) for implementation in the transportation process in railway transport. The purpose of this study is to integrate intelligent information technology into the railway transportation process using the IDEF0 functional modeling methodology. The implementation of IIT will ensure monitoring of the condition of wagons and cargo from the moment of loading to the moment of unloading along the entire route. Methods: Analysis of the current state of the subject area, synthesis of solutions, mathematical modeling, provisions of the theory of automatic control are applied. Results: World experience in the use of intelligent technologies in railway transport was analyzed, a diagram of a control system for the process of accepting a car for transportation and a mathematical model of the problem that IIT solves was developed. The role of IIT in the transportation process is determined using the IDEF0 functional modeling methodology. The importance of integrating IIT into the process of freight transportation by rail in increasing their efficiency through the use of new methods is shown.

PHASE FORMATION IN THE FeSb2S4-FeLn2S4 SYSTEM, SYNTHESIS AND PROPERTIES OF COMPOUNDS OF THE FeLnSbS4 (Ln=Nd, Er) TYPE

Phase formation in the FeSb2S4-FeNd2S4 and FeSb2S4-FeEr2S4 systems were studied by means of differential thermal analysis, X-ray diffraction technique, microstructural analysis and microhardness measurement. Phase diagrams of the title systems have been constructed and the formation of a quaternary sulfosalt with the FeLnSbS4 composition has been established. The compounds FeNdSbS4 and FeErSbS4 melt congruently at 960 and 1330 K, respectively, and form continuous substitutional solid solutions with FeSb2S4. Sulfosalts FeLnSbS4 crystallize in the orthorhombic structure with following unit cell parameters: a=11.392, b=14.132, c=3.746Å, sp.gr. Pbam, z=4, density ρ=4.88 g/cm3 (for FeNdSbS4); a=11.360, b=13.842, c=3.600 Å, sp. gr. Pbam z=4, ρ=5.17 g/cm 3 (for FeErSbS4). The FeLnSbS4 type sulfosalts is classified under the FeSb2S4 berthierite structure.

Lanthanium nitride LaN9 featuring azide units: the first metal nine-nitride as a high-energy-density material.

High-pressure phase diagrams of the La-N binary system were systematically constructed using the CALYPSO method and first-principles calculations. In addition to the pressure-induced La-N compounds reported previously, we have uncovered a hitherto unknown LaN9 structure in Pm3̄ symmetry stabilized within a narrow pressure range of 20-24.5 GPa. Notably, LaN9 stands as the first thermodynamically stable metal nine-nitrogen compound, featuring centrosymmetric linear N3 anion units and an edge-sharing LaN12 icosahedron. Charge transfer between the La and N atoms plays a crucial role in facilitating structural stability. Furthermore, we identified a novel Cm phase for LaN8, which has a lower enthalpy compared to the previously reported phase. N atoms in Cm LaN8 are polymerized into infinite N∞ chains. Calculations demonstrate the potential recoverability of LaN9 and Cm LaN8 under atmospheric conditions while preserving their initial polynitrogen configuration. From the perspective of detonation pressure and detonation velocity, LaN9 and Cm LaN8 exhibit excellent explosive performance in comparison to TNT and HMX, with estimated energy densities of 0.9 and 1.54 kJ g-1, respectively, indicating their potential utility as high-energy-density materials.

Intensifying separation of Pb and Sn from waste Pb-Sn alloy by ultrasound-assisted acid leaching: Selective dissolution and sonochemistry mechanism

Clean and efficient extraction and separation of precious metals from discarded Pb-Sn alloy is critical to the sustainable utilization of solid waste resources. Dense oxide layer and compact alloy texture in the waste Pb-Sn alloy pose challenges to the effective leaching process. Ultrasonic waves are demonstrated to improve separation efficiency via the favorable physical and chemical effects in solution system. In this study, ultrasound-assisted leaching technology is attempted to rapidly and selectively extract Pb from the waste Pb-Sn alloy, and gives emphasis on ultrasonic electrochemical behaviors. The Eh-pH diagrams of Sn-H2O and Pb-H2O systems were firstly analyzed to lay the selective dissolution foundation. It’s indicated that oxidizing HNO3 lixiviant is suitable to realize the selective separation of Pb. Both Sn and Pb can be dissolved to ionic Sn2+ and Pb2+ in the HNO3 solution. However, Sn2+ rapidly oxidizes to Sn4+ and Sn4+ further hydrolyzes to insoluble SnO2, which will agglomerate on unreacted materials to limit internal metal leaching in conventional leaching process. Due to the vibratory stripping of oxide layer by physical effect of ultrasound, the conventional acid leaching time for Pb extraction can be halved with the ultrasound assistance. About 99.12 % Pb and only 0.1 % Sn are dissolved in ultrasound-assisted leaching under the following optimal parameters: 0.5 mol/L HNO3, leaching temperature of 80 °C, time of 30 min, liquid-to-solid ratio of 20 mL/g, and ultrasound intensity of 0.52 W/cm2. Leaching kinetics of Pb, phase transition, microstructure evolution, Pb-Sn galvanic corrosion and dissolution polarization curve were studied to determine the ultrasonic enhanced dissolution mechanism. Notably, Pb and Sn form a microcorrosion galvanic cell in which Sn acts as a cathode and is protected while the Pb undergoes intensifying corrosion as the anode giving rise to the higher Pb dissolution efficiency. Eventually, it’s suggested that Pb can be rapidly extracted and separated from the waste Pb-Sn alloy during the ultrasound-assisted HNO3 leaching process via the ultrasound physical and chemical effects, especially the sonochemistry aspect of intensified spot corrosion and galvanic corrosion. The proposed ultrasonic electrochemical corrosion in this work were applicable to the extraction of valuable metals from various waste alloys through leaching method.

Продовольча система України на шляху реалізації Цілей Сталого Розвитку: передумови та сучасні виклики

The Global Sustainable Development Goals, announced by the UN General Assembly in 2015, today serve as a guideline for developing the national economy of Ukraine and its food system. The unprecedented challenges of the new millennium – the pandemic and the military aggression of the Russian Federation – distanced Ukraine from their implementation. In this regard, the article aims to reveal the prerequisites for the development of the food system and identify today's challenges to determine the most effective and efficient directions for solving problems and means of achieving the Sustainable Development Goals. The research uses the following methods: systemic generalization – to systematize the risks and challenges of the food system in the context of achieving the Sustainable Development Goals; method of comparisons and dynamic method – to assess the state of production and consumption; regression equations – to determine the forecast indicators of individual indicators of the Sustainable Development Goals and possible changes in food consumption volumes in the future. The content of the concept of sustainability and sustainable development of the food system was defined. Prerequisites for the sustainable development of the food system were identified, particularly Ukraine's leadership in food exports, the existing potential of land, and the growth of food production and consumption. The work assessed food production indices during periods of crisis, such as during a pandemic and martial law. A functional diagram of the food system's prerequisites and challenges for sustainable development in the context of the Sustainable Development Goals has been developed. An analysis of the dynamics of individual SDG indicators and trends in their development was carried out. Indicators of sufficiency of consumption of basic food products by recommended consumption standards are analyzed. The results of the study show that despite the unprecedented challenges, the food system of Ukraine is gradually adapting to modern conditions, restoring the economy and strengthening food security in the regions of Ukraine; humanitarian, economic, and economic ties are being established.