State Diagram Research Articles

Research on grid-connected photovoltaic energy storage to stabilize power fluctuations

Due to the instability of photovoltaic power generation, device aging and other factors, the PI parameters of the original PI controller were no longer applicable. So a grid-connected control strategy of photovoltaic energy storage with PI controller parameters optimized by an algorithm was proposed to realize the smooth suppression of photovoltaic power fluctuations. Firstly, the PI controller parameters of the energy storage control part were optimized by using the algorithm, and the optimization process was designed. Then, the second-order low-pass filter was used to distribute the photovoltaic power, and the energy control mode of the energy storage part was designed. Finally, the PI parameter effects of the optimized energy storage control part were displayed by comparing the DC bus voltage in the isolated state, and the power suppression effects under grid-connected condition were displayed by the mixed energy storage power. The rationality of the control mode of the energy storage part was verified by the SOC state diagram of the mixed energy storage. The results showed that the control strategy could effectively suppress pv power fluctuation.

Availability Analysis of the Critical Production System in SMEs Using the Markov Decision Model

Small and medium-sized enterprises (SMEs) in today’s world have numerous issues in ensuring the availability and safety of critical machines and their components in the working environment. As a result, SMEs considered planning and scheduling maintenance tasks to be a significant threat. The goal of this research is to identify the critical subsystem of the automobile spare parts production plant in the southern region of Tamil Nadu, India, and then to prioritize the maintenance activity and set up an architecture for autonomous preventive maintenance (PM) in SMEs that includes an optimal decision support system. The transition state diagram of the individual and simultaneous production system has been developed with the application of the Markov decision model approach. It was used to analyze the present variables of the production systems and forecast the optimal maintenance parameters such as the failure rate and the repair rate, through the production system’s availability analysis. This availability analysis reveals that system B (Piercing) is classified as the most critical because of the abrupt availability variation compared to all other production systems, concerning the corresponding maintenance parameters such as a failure rate of 0.0371, a repair rate of 0.7094, and the availability of the piercing system of 0.5056. Finally, the use of an autonomous PM management system and the most effective maintenance workforce has enhanced productivity and customer satisfaction in SMEs. The predictive maintenance management system has been further investigated to determine the real-time remaining useful life (RUL) of critical systems in the automobile spare parts manufacturing plant in the southern region of Tamil Nadu, India.

Tunable Mott Dirac and Kagome Bands Engineered on 1T-TaS2.

Strongly interacting electrons in hexagonal and kagome lattices exhibit rich phase diagrams of exotic quantum states, including superconductivity and correlated topological orders. However, material realizations of these electronic states have been scarce in nature or by design. Here, we theoretically propose an approach to realize artificial lattices by metal adsorption on a 2D Mott insulator 1T-TaS2. Alkali, alkaline-earth, and group 13 metal atoms are deposited in (√3 × √3)R30° and 2 × 2 TaS2 superstructures of honeycomb- and kagome-lattice symmetries exhibiting Dirac and kagome bands, respectively. The strong electron correlation of 1T-TaS2 drives the honeycomb and kagome systems into correlated topological phases described by Kane-Mele-Hubbard and kagome-Hubbard models. We further show that the 2/3 or 3/4 band filling of Mott Dirac and flat bands can be achieved with a proper concentration of Mg adsorbates. Our proposal may be readily implemented in experiments, offering an attractive condensed-matter platform to exploit the interplay of correlated topological order and superconductivity.

Broken-axisymmetry state and magnetic state diagram of spin-1 condensate through the prism of quadrupole degrees of freedom

We theoretically study a weakly interacting gas of spin-1 atoms with Bose–Einstein condensate in external magnetic field within the Bogoliubov approach. To this end, in contrast to previous studies, we employ the general Hamiltonian, which includes both spin and quadrupole exchange interactions as well as the couplings of the spin and quadrupole moment with the external magnetic field (the linear and quadratic Zeeman terms). The latter is responsible for the emergence of the broken-axisymmetry state. We also reexamine ferromagnetic, quadrupolar, and paramagnetic states employing the proposed Hamiltonian. For all magnetic states, we find the relevant thermodynamic characteristics such as magnetization, quadrupole moment, thermodynamic potential. We also obtain three-branch excitation spectrum of the broken-axisymmetry state. We show that this state can be prepared at three different regimes of applied magnetic field. Finally, we present the magnetic state diagrams for each regime of realizing the broken-axisymmetry state.

PhaSepDB in 2022: annotating phase separation-related proteins with droplet states, co-phase separation partners and other experimental information.

Phase separation (PS) proteins form droplets to regulate myriad membraneless organelles (MLOs) and cellular pathways such as transcription, signaling transduction and protein degeneration. PS droplets are usually liquid-like and can convert to hydrogel/solid-like under certain conditions. The PS behavior of proteins is regulated by co-PS partners and mutations, modifications, oligomerizations, repeat regions and alternative splicing of the proteins. With growing interest in PS condensates and associated proteins, we established PhaSepDB 1.0, which provided experimentally verified PS proteins and MLO-related proteins. The past fewyears witnessed a surge in PS-related research works; thus, we kept updating PhaSepDB. The current PhaSepDB contains 1419 PS entries, 770 low-throughput MLO-related entries and 7303 high-throughput MLO-related entries. We provided more detailed annotations of PS proteins, including PS verification experiments, regions used in experiments, phase diagrams of different experimental conditions, droplet states, co-PS partners and PS regulatory information. We believe that researchers can go further in studying PS proteins with the updated PhaSepDB (http://db.phasep.pro/).

Lattice Boltzmann simulation of droplet impact on orifice plate with different wettability

In this paper, simulation results of droplet impact motion on hydrophilic (θ=80°) and hydrophobic (θ=160°) orifice surfaces are obtained by a single component multiphase lattice Boltzmann model (LBM). And a piecewise relaxation time is used to improve the numerical stability under high liquid/vapor density and low droplet viscosity. The effects of Weber (We) number, Ohnesorge (Oh) number, orifice thickness, and the diameter ratio of the orifice and droplet on the deformation process of the droplet impact on hydrophilic and hydrophobic orifice plates were studied, including the phenomena of liquid slug and breakage. As a result, at a low We number, the droplet is not easy to pass through the orifice, and the liquid plug phenomenon will be formed in the hydrophilic orifice, which is because of the hydrophilic effect on the orifice surface forms capillary action. At a high We number, the droplet will break when it impacts the orifice plate. In addition, the critical We number of droplets passing through the surface of a hydrophilic orifice has a linear relationship with the thickness of the orifice, while there is a critical We number of droplets passing through the surface of a hydrophobic orifice, which corresponds to two different forms of passage: peristaltic form and rapid through the form. The state diagram of the droplet with different We number, orifice diameter and droplet diameter ratio is obtained, which can be used to predict the different states of the droplet after impacting the orifice. According to the We number and Oh number, a graph for predicting droplet rupture is obtained. The critical We number increases with the increase of The Oh number, which means that the more viscous droplet requires a larger We number to rupture.

Structural stability, mechanical, and optoelectronic properties of new stable phases for the ternary alloy Mg–Cd–O

With the development of technology, finding new crystallographic phases with remarkable properties and that are easy to be elaborated experimentally is highly recommended. The creation of alloys is one of the methods to preselect and control the physical properties of materials. Herein, density functional theory (DFT) calculations were performed to find alternatives to the well-known structures of the system MgxCd1-xO (x = 0.25, 0.50, and 0.75), and modulate their properties and even to widen the elaboration possibilities for the experimental field. The structural stability viz thermodynamic, elastic, and dynamic properties were scrutinized for new identified structures. The mechanical properties were investigated based on the elastic constants to determine the effect of increasing the atomic fraction of the studied alloy. Moreover, the band structure and density of states diagrams showed the origin, nature and values of the bandgaps indicating a blue shift of the energies for the title compounds, which makes them suitable for visible and ultraviolet optoelectronic devices. The linear optical constants were predicted and discussed accurately.

Skyrmion Dynamics in a Double-Disk Geometry under an Electric Current.

In this work, we present an analysis of skyrmion dynamics considering Dzyaloshinskii–Moriya interactions in an STNO device with a double-disk geometry. Three regimes were observed as a function of geometric parameters and the electric current density: (i) the skyrmion is annihilating at the system’s border; (ii) the skyrmion moves in a non-circular trajectory alternating its position between the two disks, and (iii) the skyrmion only rotates inside a one-disk subsystem. For the annihilation state, we found that the transient time decays within a stretched exponential law as a function of the electric current. Our results show a 2D state diagram that can guide new experimental work in order to obtain these specific behaviors for new applications based on skyrmion dynamics.

Microstructure, catalytic activity, magnetic and electronic properties of Ni3Al, Ni3Ga and Ni3Sn melt spun intermetallics from experimental and DFT computational standpoints

Structural and catalytic properties of as melt spun Ni3X (XAl, Sn, Ga) ribbons have been studied experimentally and theoretically by density functional theory calculations. All the ribbons show mostly single phase microstructures. The Ni3Ga and Ni3Al show weak magnetic behavior, whereas the Ni3Sn appears paramagnetic. The ribbons in a monolithic state are found catalytically active for semi hydrogenation of phenylacetylene. The highest conversion rate is demonstrated by the Ni3Sn ribbons. In consistence with experimental results calculated density of states (DOS) diagrams, with GGA and HSE approximations, are representative for magnetic weak-magnetic behavior, respectively. Also, the XAS, and XMCD properties have been studied. The thermodynamic phase diagram indicates that all these compounds are thermodynamically stable, yet the Ni3Al, and Ni3Ga show more stability than Ni3Sn, thus showing prospects for catalytic applications.

Development of models and improvement of methods for formalization of design problems and automating technical and operational works of railway stations

The object of research is the processes of automation of the technical and operational assessment of railway stations (RWS). Research solves the problem of developing models, methods and information technologies to automate the process of technical and operational assessment of the work of RWS. As a result of the study, the following results were obtained: Analysis of scientific papers on the problem of automating the work of RWS. Development of new method and mathematical models to automate the task. Development of new descriptions for the technological processes (TechP) of the RWS based on visual programming methods. Development of simulation models for the automation of railway infrastructure management task. The UML diagrams of state and activity have been adapted in order to represent the RWS operation technology. When formalizing the description of the RWS, the state diagrams are submitted taking into account the specifics of the description of the change in the phases of servicing objects in the process of TechP of individual objects maintenance. It is shown that the state diagram for the RWS is a state machine (SM) that models the sequence of changing the states of an object. The detalization of the behavior of objects serviced at the RWS has been completed. Detalization is performed using diagrams of activity. The diagrams of activity are used to formally describe the technical support with objects and executors of work on the railway. The scientific results obtained in the article, as well as new and improved models and methods, can be used in the development, improvement and formalization of the TechP of the RWS, research methods for informatization and automation objects on the railways of the Republic of Kazakhstan.

Prototyping a Serial Number based Authentication Model for a Computer in a Wireless Local Area Network

With the increase of wireless LAN usage in homes and enterprises due to its numerous benefits, authenticating the ever increasing number of devices and their users has become a challenge to proprietors of such kind networks. A MAC address, a physical network address that is used as basis for this study, has a copy of its value in the system software that can be spoofed and altered rendering the address not unique, not secure and unreliable. On the contrary, a computer’s serial number is hard-coded in the system hardware only and therefore cannot be spoofed and altered making it unique, secure and reliable. The research, therefore, was aimed at designing a model that demonstrates how a computer’s serial number can be used for authenticating a computer in a wireless local area network. In order to achieve the research objective, the study examined the inbuilt access and use of a computer’s serial number prototype model as an alternative method of authenticating devices in a network. Design science research methodology that involved design and development, demonstration and model evaluation was employed. A Serial Number Based Authentication prototype (SNAP) was therefore designed using state chart and flow chart diagrams based on dynamic programming, developed over evolutionary prototyping and test run on a static experimental design using Java Development Kit and MySQL platforms to demonstrate, as proof of concept, that a computer’s serial number can be used to authenticate a computer in a wireless local area network. From the test runs whose outcomes were the binary values yes or no, it was found out that SNAP can actually allow or deny, enable or disable a computer in a network based on the computer’s serial number. The researcher therefore, recommends that the prototype be scaled up, then adopted as a network device authentication method.

Parametric exploration of zero-energy modes in three-terminal InSb-Al nanowire devices

We systematically study three-terminal InSb-Al nanowire devices by using radio-frequency reflectometry. Tunneling spectroscopy measurements on both ends of the hybrid nanowires are performed while systematically varying the chemical potential, magnetic field, and junction transparencies. Identifying the lowest-energy state allows for the construction of the lowest- and zero-energy state diagrams, which show how the states evolve as a function of the aforementioned parameters. Importantly, comparing the diagrams taken for each end of the hybrids enables the identification of states which do not coexist simultaneously, ruling out a significant amount of the parameter space as candidates for a topological phase. Furthermore, altering junction transparencies filters out zero-energy states sensitive to a local gate potential. Such a measurement strategy significantly reduces the time necessary to identify a potential topological phase and minimizes the risk of falsely recognizing trivial bound states as Majorana zero modes.

Effect of glass transition on drying crack formation of maize kernels

The change of temperature and moisture content during maize ( Zea mays ) kernel drying can cause glass transition, which can lead to crack formation. However, the influence mechanism of glass transition on crack formation is not clear. This work aimed to study the effect of form and process of glass transition on the crack formation. It was found that the form and process of glass transition of maize kernels were determined by the state diagram, moisture content, temperature and state distribution. Glass transition began at the corner of the kernel and extended from the surface to the centre, which was consistent with the development of cracks. The transition form, transition rate and duration of the transition state depended on drying stage and temperature, which could effectively explain the difference in the degree of cracking. This could be helpful for understanding the crack formation mechanism and optimising the operating conditions in maize drying. • Crack formation depended on the form and process of glass transition. • Moisture content and temperature of corn kernel affected the glass transition process. • The difference of crack degree could be explained effectively by the glass transition. • Occurrence and propagation of cracks were consistent with transition of glassy state.

Dynamics and Rheology of Supramolecular Assemblies at Elevated Pressures.

A methodology to investigate the linear viscoelastic properties of complex fluids at elevated pressures (up to 120 MPa) is presented. It is based on a dynamic light scattering (DLS) setup coupled with a stainless steel chamber, where the test sample is pressurized by means of an inert gas. The viscoelastic spectra are extracted through passive microrheology. We discuss an application to hydrogen-bonding motif 2,4-bis(2-ethylhexylureido)toluene (EHUT), which self-assembles into supramolecular structures (tubes and filaments) in apolar solvents dodecane and cyclohexane. High levels of pressure (roughly above 20 MPa) are found to slow down the terminal relaxation process; however, the increases in the entanglement plateau modulus and the associated persistence length are not significant. The concentration dependence of the plateau modulus, relaxation times (fast and slow), and correlation length is practically the same for all pressures and exhibits distinct power-law behavior in different regimes. Within the tube phase in dodecane, the relative viscosity increment is weakly enhanced with increasing pressure and reaches a plateau at about 60 MPa. In fact, depending on concentration, the application of pressure in the tube regime may lead to a transition from a viscous (unentangled) to a viscoelastic (partially entangled to well-entangled) solution. For well-entangled, long tubes, the extent of the plateau regime (ratio of high- to low-moduli crossover frequencies) increases with pressure. The collective information from these observations is summarized in a temperature-pressure state diagram. These findings provide ingredients for the formulation of a solid theoretical framework to better understand and exploit the role of pressure in the structure and dynamics of supramolecular polymers.

Deformation modeling of bending element strength in MATLAB

The paper presents the strength analysis of bending reinforced concrete elements in the Matlab support package. The versatility of the deformation model is its ability to conduct control tests, for example, verification of structural analysis at the design stage. Based on the standard stress-strain state diagrams of materials and iteration procedures, two independent nonlinear analyses are suggested. One of the main accepted conditions is that iteration procedures occur at the elastic behavior of the member. Iteration procedures determine the maximum member curvature and its deformation. The strength criterion is theoretically calculated deformation, which must not exceed permissible values specified in construction codes and regulations. Calculation algorithms are given in flowcharts. In conclusion, the results of experimental data are presented.

Обґрунтування вибору скандію для мікролегування високоміцних алюмінієвих сплавів

The substantiation of the scandium selection for microalloying and modifying of high-strength aluminum alloys. The research material is a high-strength aluminum alloy B96C1 of the Al-Zn-Mg-Cu system. Scandium was chosen as a microalloy and modifying element. The state diagram of Al-Sc, physical, and mechanical properties of scandium have been studied. Modes of heat treatment of B96C1 alloy with 0.3 % scandium have been developed. The structure and mechanical properties of the modified alloy were studied. The conducted complex of studies confirmed the microleveling and modifying the action of scandium in Al-melt, the technology of the introduction of scandium into melt-melt was developed, the amount of Sc was optimized. AlSc alloys have a significant effect on artificial aging. The study of the kinetics of the decomposition process showed the supersaturation of the solid solution obtained by crystallization. During the decomposition of a solid solution of scandium in aluminum, particles of the stable phase of Al3Sc are released. Based on the analysis of the Al-Sc state diagram, the homogenization temperatures of hardening and aging of the aluminum alloy B96Ts1 with optimization of the cooling rate of the workpieces were selected. In the modified blanks, grain grinding was achieved 2.5 times and the characteristics of the yield strength and yield strength of the alloy while maintaining plasticity. For aluminum alloy B96Ts1, the choice of scandium as a microalloying and modifying element is justified in terms of compliance with its physicochemical nature and properties of aluminum-based alloys. Because of hardening the alloys of the Al-Sc system, there is no decomposition of the solid solution with the release of Al3Sc intermetallic particles, which is a scientific novelty. The main effect of scandium is to increase the strength properties due to the formation of dispersed decomposition products of a solid solution of scandium in aluminum and preservation in heat-treated semi-finished products of stable structure with small subgrains. The establishment of the technology of the introduction of scan-action into the melt and temperature-time parameters of heat treatment of workpieces allowed to obtain a dispersed structure and a high set of mechanical properties of the alloy B96Ts1, which is the practical value of the work.

Дослідження фазоутворення після дифузійного зварювання у вакуумі з’єднання нікель-ніобій

Diffusion welding is the ideal solution for joining dissimilar materials. This method is particularly effective if you should get a strong monolithic joint without the formation of a rough weld or solder seam. It is used if it is impossible to use standard fasteners. The main scope of this type of welding is the area of high technologies - aviation, space and other types of heavy engineering. All the advantages make the process indispensable under certain conditions and classify it as a high-tech type. This paper considers compounds of dissimilar metals nickel-niobium. In connection with the formation of many intermetallic compounds between these metals, the technology of diffusion welding in a vacuum was chosen. This method allows you to connect materials without melting due to the mutual diffusion of the components. The welding parameters affect the phase formation of the diffusion zone. To study the phase composition, a method of microstructural, X-ray microanalysis, as well as a state diagram of nickel-niobium, is proposed. When studying the weldability of the nickel-niobium system, samples were made in the form of a cube with a side of 10 mm, which was clamped in a mandrel and filled with Wood's alloy. The samples were not subjected to digestion, since during the polishing process, due to the different hardness of the phases, the structure turned out to be thermal polishing. The proposed scheme made it possible to study in detail the phase composition of individual layers of the diffusion zone, their dimensions and dependence on welding parameters. According to the results of quantitative X-ray microanalysis, we did not obtain accurate data on the phase composition and extent of diffuse layers. Qualitative X-ray spectral microanalysis, which was carried out by continuous scanning with an electron probe through the diffuse zone, made it possible to fix the phase reflections on the concentration curves and to determine the extent of the diffusion layers. For a more visual representation of the arrangement of the phases, a combined nickel-niobium diagram with a concentration curve is considered. The studies carried out made it possible to obtain a high-quality joint with mechanical properties that ensure reliability under operating conditions.

Y2O3‒SiO2 SYSTEM DIAGRAM

The deoxidizing ability of yttrium has not been sufficiently studied, although it has a high affinity for oxygen. In ferrous metallurgy, yttrium is often used in the form of an alloy with silicon. The effect of each of the components of the silicoyttrium alloy on the process of liquid metal deoxidation can be established by studying the Fe‒Y‒Si‒O system. The composition of the formed non-metallic inclusions in steel in this case is mainly determined by the type of oxide state diagrams of the Y2O3‒SiO2 and FeO‒Y2O3‒SiO2 systems associated with the region of existence of metallic melts. In this work, using the method of thermodynamic modeling of phase equilibrium in oxide system state diagrams and the theory of subregular ionic solutions, we analyze and calculate liquidus lines in the Y2O3‒SiO2 oxide system. A diagram of the state of this system was constructed. According to the thermodynamic analysis, the most stable in the system are three compounds ‒ oxy- Y2O3·SiO2 and yttrium orthosilicate 2Y2O3·3SiO2 (congruent melting, 1979 and 1915 °C, respectively), as well as yttrium pyrosilicate Y2O3·2SiO2 (incongruent melting), which is consistent with the literature data. In the course of the work, the enthalpies and entropies of formation of these yttrium silicates from the components of the oxide melt, as well as the melting constants of these compounds, were obtained. The area of delamination borders on the field of cristobalite at 1668 °C in the concentration range 0.593‒0.980 (ionic fraction of SiO2) or 74.5‒99.0 % (mol.) SiO2. The values of the enthalpy and entropy of yttrium silicates obtained in this work allow us to proceed to the next stage of the study – modeling the state diagram of the ternary oxide system FeO‒Y2O3‒SiO2, which is necessary to consider the interaction of yttrium and silicon with oxygen in liquid iron.

A thermal model with AC Josephson effect for a shunted superconducting weak-link

Superconducting weak-link (WL), behaving like a Josephson junction (JJ), is fundamental to many superconducting devices such as nanoSQUIDs, single-photon detectors, and bolometers. The interplay between unique nonlinear dynamics and inevitable Joule heating in a JJ leads to new characteristics. Here, we report a time-dependent model incorporating thermal effect in the AC Josephson regime for a Josephson WL shunted by a resistor together with an inductor to investigate the dynamics as well as the resulting current-voltage characteristics. We find that the dynamic regime where phase and temperature oscillate simply widens due to a pure resistive shunt. However, a significant inductive time-scale in the shunt loop, competing with the thermal time-scale, introduces high-frequency relaxation oscillations in the dynamic regime. Based on numerical analysis, we present state diagrams for different parameter regimes. Our model is a guide for better controlling the parameters in the experiments of WL-based devices.

УНИВЕРСАЛЬНАЯ АНАЛИТИЧЕСКАЯ ЗАВИСИМОСТЬ ДЕФОРМАТИВНО-ПРОЧНОСТНЫХ СВОЙСТВ АРМАТУРНЫХ СТАЛЕЙ ПРИ СИЛОВОМ РАСТЯЖЕНИИ

The article deals with topical issues of the normative methodology for calculating bending and eccentrically compressed reinforced concrete elements along normal sections. They are based on the joint use of a nonlinear deformation model, the hypothesis of flat sections, physically and geometrically linear diagrams of the mechanical state of reinforcing steels of various strengths under force tension. Attention is drawn to the significant inaccuracies of calculations when using the approximate rectilinear steel deformation modulus of constant value E = 2 105 MPa up to the steel's ultimate strength. The high degree of complexity of manual calculation is confirmed when using the actual values of the physically nonlinear steel deformation modulus, approximated by analytical dependences of high degrees. A new author's approach is presented for solving such problems by approximating the real nonlinear strain modulus to the secant strain modulus E's with simple equations for high-strength “hard” and “soft” (not high and medium strength) steels, which allows to manually calculate such problems with greater accuracy.