Minimum Loss Research Articles

Power loss minimization of an IEEE 33 bus radial distribution grid using system reconfiguration with genetic algorithm

Power loss minimization of an IEEE 33 bus radial distribution grid using system reconfiguration with genetic algorithm

Activated Graphite with Richly Oxygenated Surface from Spent Lithium-Ion Batteries for Microwave Absorption.

Designing spent graphite anodes from lithium-ion batteries (LIBs) for applications beyond regenerated batteries offers significant potential for promoting the recycling of spent LIBs. The battery-grade graphite, characterized by a highly graphitized structure, demonstrates excellent conductive loss capabilities, making it suitable for microwave absorption. During the Li-ion intercalation and deintercalation processes in battery operation, the surface layer of spent graphite (SG) becomes activated, forming oxygen-rich functional groups that enhance the polarization loss mechanism. To further control the polarization loss and achieve optimized impedance matching, reduced graphene oxide (rGO) is employed as a modifier. Herein, rGO serves as a binder, effectively combining individual SG particles. The matched Fermi levels of SG and rGO reduce the interfacial barrier, facilitating rapid electron transfer. Simultaneously, their combination forms a 3D conduction network, which not only enhances multiple scattering, reflection, and attenuation of electromagnetic waves but also provides abundant polarization centers for increased microwave absorption. As a result, the optimized SG/rGO aerogel achieves an impressive effective absorption bandwidth of 7.04GHz and accompanied by a minimum reflection loss of -51.1dB. This study broadens the scope of spent LIBs utilization and provides insights for wilder and more functional applications.

AlN/FeNi Microwave-Attenuating Ceramics with High-Efficiency Thermal Conductivity and Microwave Absorption

The integration, miniaturization, and high frequency of microwave vacuum electronics put forward higher requirements for heat-conducting and wave-absorbing integrated materials. However, these materials must balance the dispersion and isolation of wave-absorbing components to optimize absorption while maintaining the continuity of thermal conductivity pathways with low defect rates and minimal interfaces. This presents a significant challenge in achieving both high thermal conductivity and efficient wave absorption simultaneously. Here, AlN/FeNi microwave-attenuating ceramics were synthesized via non–pressure sintering in a nitrogen atmosphere. The influence of FeNi content (0–20 wt%) on the density, phase composition, microstructure, microwave-absorption properties and thermal conductivity of the composites was investigated. AlN/FeNi composites consist primarily of an AlN phase with FeNi0.0578, Fe, AlYO3, and Al5Y3O12 as secondary phases, and the microstructure is uniform and dense. As the FeNi content rises from 0 to 20 wt%, the density of the composites sintered at 1800 °C × 2 h increases from 3.3 to 3.7 g/cm3. Their X-band (2–18 GHz) dielectric constant goes up from 6.5 to 8.5, the dielectric loss factor rises from 0.1 to 0.9, and thermal conductivity diminishes from 130 to 123 W/m·K. Upon reaching an FeNi content of 20 wt%, the composite achieves a minimum reflection loss of −39.1 dB at 9.5 GHz, with over 90% absorption across an effective absorption bandwidth covering 2.5 GHz. It exhibits excellent impedance matching, electromagnetic wave-attenuation properties, a relative density of 98.6%, and a thermal conductivity of 123 W m−1 K−1. The prepared AlN/FeNi composites, with integrated outstanding microwave-absorption capabilities and thermal conductivity, holds great promise for applications in 5G communications, aerospace, and artificial intelligence.

The optimal control law of the power supplied to the wheeled vehicle in case of curvilinear movement

INTRODUCTION: Highly mobile wheeled vehicles are designed to move on roads and terrain in various road and soil conditions, which is accompanied by frequent and significant changes in traction forces and rolling resistance forces. In this regard, in order to maintain vehicle mobility and ensure low energy costs when performing transport tasks, it is necessary to continuously change the operating mode during movement from completely locked to differential in the case of a mechanical transmission. At the same time, the transmission operating mode selected by the driver is not always rational. Thus, the development of a law for controlling the power supplied to the propulsion system, ensuring minimal energy losses while maintaining vehicle mobility in widely varying road conditions, is an urgent task. PURPOSE OF THE STUDY: Increasing the energy efficiency of highly mobile wheeled vehicles by applying a control law for the power supplied to the propulsion system, adaptive to driving conditions. METHODOLOGY AND METHODS: Increasing the energy efficiency of movement can be achieved by reducing losses due to wheel slipping by controlling the power supplied to the propulsion unit. It is advisable to obtain the control law as a result of solving an optimization problem, where the loss power is chosen as the objective function, and the traction forces developed on each of the wheels are chosen as the varied values. At the same time, in order to maintain the possibility of vehicle movement, it is necessary to take into account that the total traction force on all wheels must be determined by external conditions and provided by the power plant. To solve the optimization problem, the Lagrange multiplier method was used. RESULTS AND SCIENTIFIC NOVELTY: The studies carried out made it possible to obtain in analytical form a unified law of adaptive control of the power supplied to the propulsors, applicable in a wide range of road conditions in both straight and curved motion, providing a close to optimal distribution of moments across the driving wheels of the machine, obtained as a result of numerical optimization. PRACTICAL SIGNIFICANCE: The application of the developed law for controlling the power supplied to the propulsors, based on the use in the process of movement of information only about the longitudinal and vertical forces, rotational speeds and angles of rotation of the wheels (trajectory radius), will improve the efficiency of performing transport tasks when moving a vehicle in continuously changing road conditions due to reducing the load on the driver in terms of controlling differential locks in comparison with a manual transmission both in straight and curved motion.

A compact microstrip quint-band bandpass filter using shorted stub-loaded SIRs based on the interdigital feedline structure

ABSTRACT A compact microstrip quint-band bandpass filter (BPF) composed of two pairs of shorted stub-loaded step-impedance resonators (SSLSIRs) with interdigital feedline structure is designed in this paper. The two pairs of resonators are bent and placed back-to-back on the upper and lower sides of the feedline in order to miniaturise the filter. Due to the symmetric structure of the resonators, the even-odd mode analysis method can be used to derive the resonant frequency equations. Based on the simulation, the filter is fabricated on the substrate of Rogers 4350 and measured. The measured S-parameter results are in good agreement with the simulation results. The operating frequencies of five passbands are measured at 2.2/2.8/4.3/5.4/6.7 GHz and the 3-dB fractional bandwidth (FBW) is 12.7/3.8/6.6/3.2/6.9%, respectively. The measured in-band minimal return losses and the insert losses within five passbands are 11/12/13/12/13 dB and 1.7/2.5/2.7/1.5/1.6 dB. Furthermore, the proposed BPF has good frequency selectivity with steep skirt property via the interdigital feedline structure, which yields seven transmission zeros (TZs). The four measured band-to-band isolations among the five passbands are higher than 20 dB. The filter’s total dimension occupies only 0.18 λg × 0.15 λg, where λg represents the free space wavelength corresponding to the centre frequency of the lowest passband.

Evaluating the Nutritive Value and Quality of Fodder Pea (Pisum arvense L.) Silage Added with Varying Rates of Barley (Hordeum vulgare L.) and Wheat (Triticum aestivum L. Em Thell) Cracks

Silage represents the most effective solution for addressing the deficit in quality, abundance and cost-effectiveness of roughage. The main purpose of silage production is to store fresh herbage material with high nutritional value with minimum nutrient loss. For fodder and silage production, fodder pea is grown in mixtures with cereals in different ratios, but also for the silage from the pure fodder pea using additives. Molasses and crashed cereal grains or cereal can be added to silage material in order to increase its carbohydrate content. The research was conducted to determine nutritive value and silage quality of barley and wheat cracks added at different ratios to fodder pea silage in complete randomized split-plot design with four replications. 100 g withered fodder pea sample without additives and 100 g withered fodder pea sample with 3 g, 6 g, 9 g and 12 g cracked barley were vacuumed in to the 20x26 cm plastic bags and were stored in a dark environment for a period of 45 days to facilitate fermentation at ambient temperatures ranging from 15 to 28°C. Crude protein (%), crude ash (%), dry matter (%), digestible dry matter (DDM, %), dry matter intake (DMI, %), ADF (%), NDF (%), P (%), K (%), Ca (%), Mg (%), total digestible nutrients (TDN), Nel, NEm, Neg, pH, Fleig Score and RFV of pure fodder pea and cracked barley and wheat added silages were determined. According to results, fodder peas, which have a high protein and low carbohydrate content, be ensiled by the addition of high-carbohydrate wheat and barley cracks in order to obtain a quality silage. For this purpose, it is suggested to add at least 6% wheat cracks or 9% barley cracks to fodder pea silage.

Bamboo-Inspired Hierarchically Hollow Aerogel MXene Fibers with Ultrafast Ionic Channels and Multiple Electromagnetic Wave Attenuation Routes Toward High-Performance Supercapacitors and Microwave Absorption.

2D materials feature large specific surface areas and abundant active sites, showing great potential in energy storage and conversion. However, the dense, stacked structure severely restricts its practical application. Inspired by the structure of bamboo in nature, hollow interior and porous exterior wall, hollow MXene aerogel fiber (HA-Ti3C2TX fiber) is proposed. Owing to continuous porous microstructure and optimized hollow cavity, this fiber possesses large accessible area to ions and abundant structural defects, leading to a fast charge transfer kinetics and high faradic activity. Consequently, the HA-Ti3C2TX fiber exhibits exceptional gravimetric capacitance of 355 F g-1. Besides, the solid-state asymmetric fiber-shaped supercapacitors (FSCs) display a high capacitance of 276 F g-1 and energy density of 9.58 Wh kg-1. Additionally, the HA-Ti3C2TX fiber delivers outstanding electromagnetic wave (EMW) absorption performance with a minimum reflection loss of -52.39 dB and the effective absorption bandwidth up to 4.6 GHz, which is attributed to multiple reflection paths, strong dielectric loss from this hollow and porous structure. This novel design of hollow fiber provides a new reference for the construction of advanced fibers for energy storage and EMW absorption materials.

AI-Driven Medical Chatbot for Predicting and Managing Infectious Diseases

This paper explores the potential of chatbots to enhance the medical field by combating infectious diseases, including respiratory illnesses, zoonotic diseases, and viral outbreaks such as COVID-19. By increasing awareness among users, these chatbots can help individuals discover medical solutions to prevent and manage these conditions. We have developed a training model that facilitates better human interaction with databases through natural language processing, tailored to characterize users effectively. Our proposed AI chatbot model employs a recurrent neural network to ensure efficient interaction and prediction, addressing current deficiencies in guidelines for improving lifestyle programs. The model achieves a minimum loss of 0.112 and a maximum accuracy of 93. Additionally, this paper investigates the feasibility of implementing chatbots to offer 24/7 support, broaden healthcare services, and deliver personalized, real-time responses. Our conclusion emphasizes the capabilities, benefits, and challenges faced by healthcare chatbots during pandemics. This research aims to guide the development of chatbot technology, ensuring it remains innovative and effective in preventing infectious diseases, ranging from viral infections like influenza to emerging global health threats

Ultra-miniaturized Bloch mode metasplitters for one-dimensional grating waveguides.

We present, for the first time, to our knowledge, power splitters with multiple channel configurations in one-dimensional grating waveguides (1DGWs) that maintain crystal lattice-sensitive Bloch mode profiles without perturbation across all output channels, all within an ultra-miniaturized footprint of just 2.1 × 2.2 μm2. This novel capability reduces the need for transition regions, simplifies multi-channel configurations of 1DGWs, and maximizes the effective use of chip area. The pixelated metamaterial approach, integrated with a time-domain heuristic algorithm, is utilized to concurrently achieve broadband operation, optimized dispersion control, and minimal loss. We experimentally demonstrate that the 1 × 2 and 1 × 3 metasplitters achieve average minimum losses per channel of 3.80 dB and 5.36 dB, respectively, which are just 0.80 dB and 0.59 dB above ideal splitting. The measurements for both designs demonstrate a 1 dB bandwidth of 15 nm, with excellent uniformity across all output channels. These versatile metasplitter designs can serve as fundamental building blocks for ultrahigh-bandwidth, densely integrated photonic circuits and in scenarios where slow light is essential.

Multi-Objective Coordinated Control of Smart Inverters and Legacy Devices

This work proposes multi-objective two-stage distribution optimal power flow (D-OPF) to coordinate the use of smart inverters (SIs) and existing voltage control legacy devices. The first stage of multi-objective D-OPF aims to solve a mixed-integer nonlinear programming (MINLP) formulation that minimizes both voltage variation and active power loss, with SI modes, SI settings, voltage regulator (VR) taps, and capacitor bank (CB) status as control variables. The Pareto Optimal Solutions obtained from the first-stage MINLP are used to determine the optimal active–reactive power dispatch from the SIs by solving a nonlinear programming formulation in the second stage of the proposed D-OPF. This model guarantees that the setpoints for active–reactive power align with the droop characteristics of the SIs, ensuring practicability and the autonomous dispatch of active–reactive power by the SIs according to IEEE 1547-2018. The effectiveness of the proposed method is tested on the IEEE 123 distribution network by contrasting the two proposed D-OPF models, with one prioritizing SIs for voltage control and power loss minimization and the other not prioritizing SIs. The simulation results demonstrate that prioritizing SIs with optimal mode and droop settings can improve voltage control and power loss minimization. The proposed model (with SI prioritization) also reduces the usage of traditional grid control devices and optimizes the dispatch of active–reactive power. The POS also shows that the SI modes, droops, and legacy device settings can be effectively obtained based on the desired objective priority.

High-Performance Thermoelectric Composite of Bi2Te3 Nanosheets and Carbon Aerogel for Harvesting of Environmental Electromagnetic Energy.

Intensifying the severity of electromagnetic (EM) pollution in the environment represents a significant threat to human health and results in considerable energy wastage. Here, we provide a strategy for electricity generation from heat generated by electromagnetic wave radiation captured from the surrounding environment that can reduce the level of electromagnetic pollution while alleviating the energy crisis. We prepared a porous, elastomeric, and lightweight Bi2Te3/carbon aerogel (CN@Bi2Te3) by a simple strategy of induced in situ growth of Bi2Te3 nanosheets with three-dimensional (3D) carbon structure, realizing the coupling of electromagnetic wave absorption (EMA) and thermoelectric (TE) properties. With ultra-low thermal conductivity (0.07 W m-1 K-1), the CN@Bi2Te3 composites achieved a minimum reflection loss (RL) of 51.30 dB and an effective absorption bandwidth (EAB) of 6.20 GHz at an optimal thickness of 2.8 mm. Additionally, under a temperature gradient of 80 K, the flexible thermoelectric generator (FTEG) system generates a maximum output power of 42.2 μW. By absorbing 2.45 GHz microwaves to build the temperature difference, the EMA-TE-coupled device achieves an optimal Uoc of 38.4 mV, a short-circuit current of 1.03 mA, and an output power of 9.87 μW upon a radiation time of 50 s. This work establishes a potential pathway for further recycling electromagnetic energy in the environment, which is also promising for the preparation of large-area flexible EM to electrical energy conversion devices.

Multiobjective distribution system operation with demand response to optimize solar hosting capacity, voltage deviation index and network loss

In this research, demand response impact on the hosting capacity of solar photovoltaic for distribution system is investigated. The suggested solution model is formulated and presented as a tri-objective optimization that consider maximization of solar PV hosting capacity (HC), minimization of network losses (Loss) and maintaining node voltage deviation (VDev) within acceptable limits. These crucial objectives are optimized simultaneously as well as individually. To assess the efficacy of the solution, different multi-objective case studies are scrutinised based on the combinations of (i) HC and Loss, (ii) HC and VDev, (iii) Loss and VDev, (iv) HC Loss and VDev simultaneously with the effect of demand response. The multi-objective research problem is formulated as non-linear and non-convex programming approach. To solve this complex problem, the modified crow search optimization (MCSO) is proposed. The MCSO achieved the 0.0714 MW of network loss with the optimal integration of distributed generation and is comparable to the well-established optimization algorithms available in literature. From the simulation results, it is found that HC is 3322.31 kW, VDev is 0.4982 p.u and system losses is 1314.86 kWh with demand response program when all the objectives are simultaneously optimized. The simulation outcomes highlight the superiority of the MCSO over others. The application results show the benefits and the beauty of proposed research work.

Boosting Impedance Matching by Depositing Gradiently Conductive Atomic Layers on Porous Polyimide for Lightweight, Flexible, Broadband, and Strong Microwave Absorption.

Gradient structures are effective for microwave absorbing but suffer from inadequate lightweight and poor flexibility, making them fall behind the comprehensive requirements of electromagnetic protection. Herein, we propose a hierarchical gradient structure by integration with porous and sandwich structures. Specifically, polyimide (PI) foams are used as a robust and flexible skeleton, in which the foam cell walls are sandwiched by Ti3C2Tx, ZnO, and ZrO2 atomic layers in sequence. Owing to the decreasing conductivity of Ti3C2Tx, ZnO, and ZrO2, they form gradient impedance matching layers on both sides of the PI foam cell walls, significantly enhancing the absorbing intensity for microwaves. In addition, the porous and sandwich structures can synergistically facilitate multiple reflections, increasing the number of interactions between microwave and foam cell walls. Therefore, the resulting lightweight ZrO2@ZnO@Ti3C2Tx@PI (ZrZnTP) composite foams reach a minimum reflection loss of -68.4 dB with an effective absorbing bandwidth covering the whole X band (8.2-12.4 GHz). The ZrZnTP also exhibits outstanding flexibility even at an extremely low temperature of -196 °C (i.e., liquid nitrogen). This work offers a general approach to realizing hierarchically integrated structures of gradient, porousness, and sandwich structures for lightweight, flexible, broadband, and strong microwave absorbing materials.

Facile fabrication of cellulose-derived flawed graphite carbon with low-frequency minimum reflection loss in the C bands

Developing strong electromagnetic (EM) wave absorbing materials to solve the issue of EM radiation emanating from electronic devices in low-frequency range remains currently a great challenge. The majority of current solutions in low-frequency range are based on magnetic absorbent. However, this approach is constrained by the poor impedance matching, high production cost and limited absorption bandwidth. Herein, the novel reproducible cellulose-derived flawed graphite carbon material (represented as CFGC) was prepared by chemical and following simple carbonization method. Besides, the unique defect structure and the mechanism underlying microwave absorption (MA) are elaborated in detail. By fine-tuning the content of CFGC, the MA property is optimized. The minimum reflection loss (RLmin) of 50wt% filling for CFGC is –42.08dB at 4.08GHz, showing an excellent MA property within the low-frequency range of C bands. Thus, the novel CFGC in this study provides a new and convenient way to solve low-frequency EM pollution.

Hierarchical core-shell transitional metal chalcogenides Co9S8/ CoSe2@C nanocube embedded into porous carbon for tunable and efficient microwave absorption

In the domain of electromagnetic (EM) wave absorbing materials, the selection of suitable components and microstructures is an effective approach for designing the intense coupling of wave impedance and EM dissipation. In this study, we have successfully fabricated a double-carbon modified Co9S8/CoSe2 nanocube, where the core-shell Co9S8/CoSe2@C cube was anchored onto porous carbon (PC). The existence of three-dimensional (3D) porous carbon and the fabrication of Co9S8/CoSe2@C distributed on carbon nanosheets contribute to the improvement of conduction, magnetic losses, and the optimization of impedance matching. Substantial heterogeneous interfaces are generated between Co9S8, CoSe2, carbon shells, and PC, leading to extensive interfacial polarization and facilitating the transformation of EM energy into thermal energy. The abundant defects, S and Se vacancies in carbon component can act as polarization centers, inducing dipolar polarization and thus increasing the electromagnetic wave (EMW) loss. The Co9S8/CoSe2@C@PC exhibits the best microwave absorption properties, with a minimum reflection loss (RLmin) of −64.1 dB at 2.5 mm and an effective absorption bandwidth (EAB) of 6.3 GHz. The High-Frequency Structure Simulator results indicate the RCS values of the samples within the range of -90 °C < θ < 90 °C are lower than -20 dB m2, which can achieve almost full-angle coverage in the actual environment. This research offers inspiration and strategies for the design and synthesis of multi-component magneto-electric composites based on transitional metal chalcogenides.

PVP-assisted MOF-derived Fe3O4/C powders for microwave absorption applications.

Metal-organic framework (MOF) derived porous Fe3O4/C powders were applied for absorption of microwaves in the frequency range of 1-18GHz. The effects of the polyvinylpyrrolidone (PVP) additive on the synthesis of MIL101-(Fe) precursor were studied by various characterization methods. By adding PVP, the impure hematite phase (α-Fe2O3) with magnetite phase (Fe3O4) was disappeared and the particular morphology was transformed to the porous rod-like, leading to the increase of specific surface area from 150 to 282m2/g. Furthermore, the saturation magnetization (Ms) of Fe3O4/C powders reached a maximum value of 47 emu/g at a proper amount of PVP. A thin absorber (2.6mm) made of 50wt% Fe3O4/C powders and 50wt % paraffine absorbed the whole of X frequency band (8-12GHz) with a minimum reflection loss of -20 dB at a matching frequency of 10GHz. Adjusting the permittivity and permeability parameters of the Fe3O4/C powders via adding PVP was responsible for their better microwave absorption performance.

Bio-derived graphitic carbon microspheres: A green approach for high-frequency microwave absorption

Bio-derived carbon materials have emerged as a sustainable alternative to non-renewable petroleum-based carbon sources, thanks to their reproducibility and environmental benefits. There is a strong demand for developing and efficiently utilizing carbon-based microwave absorbing materials (MAMs) that are lightweight, require low filler loading, and offer broadband absorption for electromagnetic wave (EM) applications. In this context, we successfully synthesized uniform carbon microspheres from the natural precursor turpentine oil using the chemical vapor deposition (CVD) technique at various temperatures. The sample prepared at 1000 °C (GC-1000) exhibited a uniform carbon microsphere morphology, as confirmed by XRD and Raman spectroscopy, and demonstrated extremely good microwave absorption properties. With a low filler loading of just 5 wt%, the GC-1000 sample achieved a minimum reflection loss (RL) of −39.77 dB at 10.21 GHz and an effective absorption bandwidth of 2.51 GHz at a matching thickness of only 2.8 mm. Additionally, this sample showed a total shielding effectiveness (SET) of −44.74 dB, surpassing the threshold required for commercial applications. The graphitic phase formation, confirmed by XRD and Raman analysis, acts as a conductive trap for electromagnetic radiation, and the high surface area of the uniform carbon microspheres facilitates multiple internal reflections, enhancing overall microwave absorption performance in the X-band region. Our lightweight, durable, bioderived carbon microspheres, synthesized through a cost-effective and scalable process, show significant potential for EM wave absorption in military and electromagnetic compatibility (EMC) devices.

Influence of Varying Particle Size on Mechanical &amp; Tribological Properties of A356-Al2O3 Metal Matrix Composites

MMCs represent a new generation of engineering materials in which a strong ceramic reinforcement is incorporated into a metal matrix to improve its properties including specific strength, specific stiffness, wear, corrosion resistance and elastic modulus. Aluminium oxide and silicon carbide powders in the form of fibers and particulates are commonly used as reinforcements in MMCs and the addition of these reinforcements to aluminum alloys has been the subject of a considerable amount of research work. Aluminum oxide and silicon carbide reinforced aluminum alloy matrix composites are applied in the automotive and aircraft where the tribological properties of these materials are considered important. Therefore, the development of aluminum matrix composites is receiving considerable emphasis in meeting the requirements of various industries. An economical way of producing metal matrix composite is the incorporation of the particles into the liquid metal and casting which leads to improvement in strength over the unreinforced alloy. Addition of particulate reinforcement improves stiffness, strength and tribological properties. Particle size also influences the uniformity of distribution of reinforcement in the matrix. Smaller the particle size, higher will be the agglomerate content in the composite structure. Particle also directly influences the porosity content in the composite structure.The purpose of research in Tribology is understandably the minimization of losses resulting from friction and wear at all levels of technology where the rubbing of surfaces is involved. The present work is a small attempt made to study the influence of reinforcement particulate size on the mechanical and tribological characteristics of Al-Al2O3p composites.

STUDY OF EXCHANGE REACTIONS IN THE SrO-BaO-Al2O3 -SiO2 SYSTEM

Scientific research in the field of nanotechnology and composite materials for aviation and space technology contributes to the creation of new types of radio-transparent materials with improved properties. The need for these materials is especially growing in conditions of high temperature, high speed and aggressive external environment, where traditional polymer or composite materials cannot provide the necessary level of key properties. Ceramic materials made on the basis of target phases of the SrO-BaO-Al2O3 -SiO2 system have low dielectric properties and are quite promising for use in various fields where high transparency for electromagnetic waves with minimal losses is important. In this regard, a more detailed study of its subsolidus structure is relevant. This article deals with the flow of exchange reactions of the type аА+бВ = сС+дД in the volume of the SrO-BaO-Al2O3 -SiO2 concentration tetrahedron. The paper presents the results of Gibbs free energy calculations for exchange reactions in the considered system. The temperature intervals for the existence of separate combinations of phases are indicated and the formed elementary triangles are graphically presented. Based on the results of theoretical studies, it was established that in the SrO-BaO-Al2O3 -SiO2 system there is a possibility of five exchange reactions of the type аА+вВ = сС+дД. It was found that BaAl2Si2O8 – SrAl2O4 and Sr3Al2O6 – Ba2SiO4 anodes are present in the temperature range of 300...1700 K. The presence of a combination of "filled triangle" phases – Sr2Al2SiO7-2SrSiO3-BaSiO3 in the temperature range of 300...800 K was confirmed, and the existence of a combination of "filled circuit" phases – BaSiO3 – BaAl2O4 – Sr2Al2SiO7 in the temperature range of 1200...1700 K was confirmed. The discovery of this combination of phases makes it possible to expand the existing area in the experimental system for creating high-temperature ceramic materials. In turn, according to the obtained data of thermodynamic calculations, it was established that at temperatures below 1200 K, the target phases of the considered system, Ba2SiO4 and SrAl2Si2O8, do not interact with each other, and the reaction is thermodynamically disadvantageous.

Study of Optical, Thermoelectric, and Mechanical Behaviors of Double PerovskitesCs2SnVX6(X = Cl, Br, I) for Renewable Energy

Abstract Double perovskites are emerging materials for solar cells and renewable energy applications. Here this research emphasizes the optical, transport, and mechanical characteristics of Cs2SnVX6 (X = Cl, Br, I) for renewable energy. The structural and dynamic stabilities of these double perovskites in the cubic phase have been ensured by the tolerance factor (0.94, 0.93, 0.91) and the Ab initio molecular dynamic (AIMD) simulation. Furthermore, formation energy and elastic constants have also been reported, which provide evidence of thermodynamic and mechanical stability. The band gaps analyzed by TB-mBJ potential are 1.48 eV, 1.29 eV, and 0.22 eV for the Cs2SnVCl6, Cs2SnVBr6, and Cs2SnVI6, respectively. The band gap of Cs2SnVBr6 is standard for solar cells. The absorption band exists in the visible to infrared zone, with minimal optical losses. The transport behavior has been addressed through the BoltztraP code, whose large thermoelectric performance has been confirmed by the figure of merit (1.10, 0.90, 0.65) at 300K, and ultralow lattice thermal conductivity. From mechanical analysis, it is assumed that Cs2SnVCl6 has a ductile nature (B/G = 2.0) while Cs2SnVBr6 and Cs2SnVI6 have a brittle nature (B/G = 1.26, 0.94). Moreover, their hardness, large Debye, and melting temperature are also important for device fabrication.