Electrical Control Research Articles

Nonvolatile switchable half-metallicity and magnetism in the MXene Hf2MnC2O2/Sc2CO2 multiferroic heterostructure.

Nonvolatile electrical control of two-dimensional (2D) van der Waals (vdW) magnetism is important for spintronic devices. Here, using first-principles calculations, we systematically investigated the magnetic properties of the MXene Hf2MnC2O2 combined with the ferroelectric MXene Sc2CO2. When flipping the electric polarization of Sc2CO2, a transition between a semiconductor and a half-metal occurs in the Hf2MnC2O2 monolayer. Moreover, the ferromagnetic exchange parameter J1 can be enhanced to 9.67 meV under polarized P↑ of Sc2CO2, much larger than those of the pristine Hf2MnC2O2 monolayer and Hf2MnC2O2/Sc2CO2-P↓. In addition, the easy magnetization axis of the Hf2MnC2O2 monolayer is also dependent on the polarization orientation of Sc2CO2. Our results indicate a multiferroic heterostructure based on MXenes, offering an effective way for obtaining nonvolatile electrical control of electronic and magnetic properties.

Two-dimensional multiferroic RuClF/AgBiP2S6 van der Waals heterostructures with valley splitting properties and controllable magnetic anisotropy.

The investigation of new properties in two-dimensional (2D) multiferroic heterostructures is significant. In this work, the electronic properties and magnetic anisotropy energies (MAEs) of 2D multiferroic RuClF/AgBiP2S6 van der Waals (vdW) heterostructures are systematically studied by first principles calculations based on density functional theory (DFT). The Hubbard on-site Coulomb parameter (U) of Ru atoms is necessary to account for the strong correlation among the three-dimensional electrons of Ru. RuClF/AgBiP2S6 heterostructures in different polarizations (RuClF/AgBiP2S6-P↑ and RuClF/AgBiP2S6-P↓) are ferromagnetic semiconductors with stable structures. Valley polarizations are present in the band structures of RuClF/AgBiP2S6 heterostructures with spin-orbit coupling (SOC), the valley splitting energies of which are 279 meV and 263 meV, respectively. The MAEs of RuClF/AgBiP2S6 heterostructures indicate perpendicular magnetic anisotropy (PMA), which are primarily attributed to the differences in matrix elements within Ru (dyz, dz2) orbitals. In addition, valley splittings and MAEs of RuClF/AgBiP2S6 heterostructures are modified at different biaxial strains. Specifically, the highest valley splittings are 283 meV and 287 meV at ε = 2%, while they disappear at ε = -6%. The PMA of RuClF/AgBiP2S6-P↑ is gradually decreased at biaxial strains of -6% to 2%, and MAE is transformed into in-plane magnetic anisotropy (IMA) at ε = 4%. RuClF/AgBiP2S6-P↓ maintains PMA at different strains. The study of non-volatile electrical control of valley splitting phenomena in multiferroic RuClF/AgBiP2S6 heterostructures is crucial in the field of valleytronic devices, which has important theoretical significance.

Risk assessment and electrical control of high-permeability renewable energy photovoltaic system under extreme weather conditions

Abstract High-permeability photovoltaic (PV) systems are a key technical way to bring about new energy changes in electric power networks. Risk assessment and electrical regulation during extreme weather can make PV systems with high permeability work much more efficiently during severe weather. We establish an operational risk model for a high penetration rate PV system using the PV probability model, load parameter model, and probabilistic trend calculation model. Based on the results of the tidal current calculation, the risk assessment indexes of PV systems are constructed, including the voltage overrun risk index and branch circuit tidal current overrun risk index. The Monte Carlo simulation method using the Latin hypercubic sampling method is used to simulate the operational loads of PV systems under extreme weather conditions such as windy, rainy, and snowy conditions and to form a fault simulation set. Finally, we implement the QMC method to assess the risk of PV systems with high permeability and use the RBF neural network design to achieve automatic control of PV electrical equipment. When the weather is the same extreme, the risk of overrun at each node goes up with the number of nodes. When the weather is different, the risk of voltage overrun at each node under ice-covered load goes up by about half compared to rain load, and the risk of active overrun at each branch goes up by almost six times compared to rain load.

Overcoming Barriers in Photodynamic Therapy Harnessing Nanogenerators Strategies.

Photodynamic therapy (PDT) represents a targeted approach for cancer treatment that employs light and photosensitizers (PSs) to induce the generation of reactive oxygen species (ROS). However, PDT faces obstacles including insufficient PS localization, limited light penetration, and treatment resistance. A potential solution lies in nanogenerators (NGs), which function as self-powered systems capable of generating electrical energy. Recent progress in piezoelectric and triboelectric NGs showcases promising applications in cancer research and drug delivery. Integration of NGs with PDT holds the promise of enhancing treatment efficacy by ensuring sustained PS illumination, enabling direct electrical control of cancer cells, and facilitating improved drug administration. This comprehensive review aims to augment our comprehension of PDT principles, explore associated challenges, and underscore the transformative capacity of NGs in conjunction with PDT. By harnessing NG technology alongside PDT, significant advancement in cancer treatment can be realized. Herein, we present the principal findings and conclusions of this study, offering valuable insights into the integration of NGs to overcome barriers in PDT.

Gated spin manipulation in a bipolar Rashba semiconductor: a Janus TeSSe monolayer.

It is very important to realize the electronically controlled spin direction for spintronic devices. Inspired by the bipolar Rashba semiconductor (BRS) concept recently proposed by Yang's group (X. Fu, et al. J. Phys. Chem. Lett., 2023, 14(50), 11292-11297), which presented a novel solution for spin precession manipulation using a BRS, through first-principles calculations, we confirm that Janus TeSSe is a BRS. Therefore, in a spin field-effect transistor based on BRS Janus TeSSe, the spin texture direction can be electronically controlled by applying a gate voltage. We describe in detail the special opposite spin texture of Janus TeSSe, and how the gate voltage regulates the spin direction of the physical mechanism. Furthermore, the regulation of the energy band and Rashba coefficient by charge doping, external electric field, and strain engineering is studied. In summary, we propose a new Janus BRS TeSSe monolayer capable of achieving electrical control of rotation through electrical gating, which enriches the family of two-dimensional BRS materials and inspires experimental researchers to conduct studies related to spin manipulation.

Design, Development and Characterization of Indigenously Developed High Temperature Black Body Source for Calibration of ECE Diagnostics

The design, development, and characterization of a Silicon Carbide (SiC) based hightemperature black body source at 600 ºC for Electron Cyclotron Emission (ECE) measurements has been done. The design has been optimized for higher emissivity performance in 65-140 GHz frequency range using CST Microwave Studio. The innovative design features a pyramid-based structure, incorporating a heater and emitter surface, integrated with an electrical control system. The improvement in emissivity with variation in pyramid slant angle was analysed. The design was refined to ensure surface temperature consistency within a range of ± 15 ºC and rapid heating, taking less than 60 minutes to reach 600 ºC from room temperature. The developed black body calibration source was thermally characterized using IR camera for different set of temperatures and mean temperature distribution was determined. The microwave characterization of the calibration source has been performed in 65–220 GHz frequency range using Vector Network Analyser (VNA) and reflectivity of more than 20 dB has been obtained. The results highlight the synergy between advanced design methodologies, and precise engineering, leading to the development of an efficient SiC-based black body source. This research work not only contributes significantly to the field of engineering but also paves the way for enhanced accuracy and reliability in ECE measurements.

PI-based direct torque control of PMSM for torque ripple reduction

This paper addresses the challenge of torque ripple in Permanent Magnet Synchronous Motors (PMSMs) through the implementation of a Proportional-Integral (PI)-based Direct Torque Control (DTC) strategy. Torque ripple, a phenomenon affecting motor performance, is mitigated by leveraging the simplicity and fast response of DTC, augmented by the precision of PI controllers. The objectives encompass a comprehensive understanding of PMSM characteristics, the design and implementation of the PI-based DTC system in MATLAB Simulink, and an in-depth analysis of its performance in torque ripple reduction. The paper also involves comparative studies with traditional control methods, parameter tuning for optimization, and assessments of versatility under varying conditions. By achieving these objectives, the research contributes to the advancement of control strategies for PMSMs, enhancing their efficiency and adaptability in industrial applications. The outcomes are documented and presented, providing valuable insights for future advancements in electric motor control.

Uncertainty Detection in Supervisor–Operator Audio Records of Real Electrical Network Operations

The quality of verbal communication, understood as the absence of uncertainty in the message transmitted, is a key factor in mission-critical processes. Several processes are handled by direct voice communication between these endpoints and any miscommunication could have an impact in success of the task. For that reason, the quality control of verbal communication is required to ensure that the instructions issued are effectively understood and adequately executed. In this context, it is expected that instructions from the command center are issued once, and that the acknowledgment from the field are minimal. In the present work, the communication between an electrical company control center and factory workers in the field was chosen for analysis. We developed two complementary approaches by using machine learning and deep learning algorithms to assess, in an automatic way, the quality of information transmission in the voice communications. Preliminary results demonstrate that the automatic uncertainty detection is feasible, despite the small number of samples available at the present time. To support further studies, a repository was created in GitHub with the spectrogram and the tokenized words of all audios.

Coupled chemical reactions: Effects of electric field, diffusion, and boundary control.

Chemical reactions involve the movement of charges, and this paper presents a mathematical model for describing chemical reactions in electrolytes. The model is developed using an energy variational method that aligns with classical thermodynamics principles. It encompasses both electrostatics and chemical reactions within consistently defined energetic and dissipative functionals. Furthermore, the energy variation method is extended to account for open systems that involve the input and output of charge and mass. Such open systems have the capability to convert one form of input energy into another form of output energy. In particular, a two-domain model is developed to study a reaction system with self-regulation and internal switching, which plays a vital role in the electron transport chain of mitochondria responsible for ATP generation-a crucial process for sustaining life. Simulations are conducted to explore the influence of electric potential on reaction rates and switching dynamics within the two-domain system. It shows that the electric potential inhibits the oxidation reaction while accelerating the reduction reaction.

Active Huygens’ metasurface based on in-situ grown conductive polymer

Abstract Active metasurfaces provide unique advantages for on-demand light manipulation at a subwavelength scale for emerging visual applications of displays, holographic projectors, optical sensors, light detection and ranging (LiDAR). These applications put stringent requirements on switching speed, cycling duration, electro-optical controllability, modulation contrast, optical efficiency and operation voltages. However, previous demonstrations focus only on particular subsets of these key performance requirements for device implementation, while the other performance metrics have remained too low for any practical use. Here, we demonstrate an active Huygens’ metasurface based on conductive polyaniline (PANI), which can be in-situ grown and optimized on the metasurface. We have achieved simultaneously on the active metasurface switching speed of 60 frame per second (fps), switching duration of more than 2000 switching cycles without noticeable degradation, hysteresis-free controllability over intermediate states, modulation contrast of over 1400 %, optical efficiency of 28 % and operation voltage range within 1 V. Such PANI-powered active metasurface design can be readily incorporated into other metasurface concepts to deliver high-reliability electrical control over its optical response, paving the way for compact and robust electro-optic metadevices.

Skyrmion qubits: Challenges for future quantum computing applications

Magnetic nano-skyrmions develop quantized helicity excitations, and the quantum tunneling between nano-skyrmions possessing distinct helicities is indicative of the quantum nature of these particles. Experimental methods capable of nondestructively resolving the quantum aspects of topological spin textures, their local dynamical response, and their functionality now promise practical device architectures for quantum operations. With abilities to measure, engineer, and control matter at the atomic level, nano-skyrmions present opportunities to translate ideas into solid-state technologies. Proof-of-concept devices will offer electrical control over the helicity, opening a promising new pathway toward functionalizing collective spin states for the realization of a quantum computer based on skyrmions. This Perspective aims to discuss developments and challenges in this new research avenue in quantum magnetism and quantum information.

INCREASE OF PRODUCTIVITY OF THE CHEMICAL ENTERPRISE TERMS OF COORDINATION OF WORK OF ELECTRICAL PROTECTION AND TECHNOLOGICAL AUTOMATION

The coke oven gas purification workshop is connected to the main workshops of the coke-chemical production plant. In our warehouse, we have a large amount of electrical and chemical equipment that operates in a continuous mode. Analysis of the disruption of the technological process shows that one of the main reasons is the absence of an automatic control system and control of the flowing processes in the devices, as well as the possibility of reducing the quality of care from the norm without interruption. ladnannya. Therefore, when creating a selectivity map for relay controllers, it is necessary to take into account the specifics of the technological equipment. The installation of the automated complex "RADICAL" gave a significant economic effect: the supply of coke oven gas to the thermal power plant increased by 4 %, or by 5.2 million cubic meters, which allowed an increase in the production of electricity by 780 million kW-year and generation acid by 5 % (total for 400 tons). An additional effect was ensured by the reduction of the staff of operators to 12 people. However, the main effect was due to the increased reliability of the technological installation. The analysis showed that the production process causes significant disruption to the technological process. The main share of disruption to the technical process is due to the insufficient operation of electrical controls and technological automation. The introduction of an automated treatment and control system of the “RADICAL” type into the robot significantly changed the level of disruption to the technical process, increased the reliability of the technological equipment of the robot and gave a significant economic effect.

A Device Model for Achieving Sizable and Tunable Tunneling Magnetoresistance Using Two‐Dimensional Materials InX (X = O, Se) without Hetero‐Interface

AbstractThe two‐dimensional (2D) materials InX (X = O, Se), experimentally available thus far, can become a ferromagnetic half metal under hole doping, though the charge neutral states of them are nonmagnetic semiconductors. Based on such an electronic characteristic, a theoretical model of magnetic tunnel junction (MTJ) is proposed composed only of one of the 2D InX. In doing so, the two semi‐infinite pieces of 2D InX in the half‐metallic state is assumed as the opposite electrodes which are separated by a strip of the same material but in its nonmagnetic state. Owing to the 2D nature of InX, the half metal electrodes of the InX device induced by hole doping can be achieved by using split gating technique. The numerical simulations identify a proper hole doping concentration, at which 100% tunneling magnetoresistance (TMR) ratios can be realized, accompanying an appreciable conductance of majority spin electron under parallel magnetization configuration. Under a finite bias voltage, the TMR ratio remains high. Therefore, the proposed device model is an ideal candidate for future spintronics applications. It enables electrical control of TMR and circumvents the detriment of hetero‐interface disorder inevitable in conventional MTJs.

Electrochemically Activated Multifunctional Carbon Fibre Composites

A multifunctional lightweight material combines several functions in a single material entity able to simultaneously bear mechanical loads by acting as a carbon fibre composite component while providing one or more other functionalities at the same time, e.g. storing energy. Carbon fibres are particularly attractive as they can be used both as a high-performance structural material and as an active electrochemical material. Carbon fibres allow for ion insertion into their microstructure with capacities comparable to graphite and hard carbon used in state-of-the-art lithium-ion and other alkali-ion batteries [1]. Carbon fibres are electrically conductive and can therefore replace the conventional metallic current collector. Carbon fibres are thus in this context a truly multifunctional material. A piezo-electrochemical transducer effect (PECT) [2], has also been discovered in ion inserted carbon fibres. The PECT-effect, that mechanical load changes the electrochemical potential of ion-inserted materials, could be used for sensing, where a voltage change is related to the mechanical strain in the material. When carbon fibres are inserted with alkali ions, they expand in the axial direction [3]. This expansion could be used for making linear actuators with high forces or even to create shape-morphing materials [4]. Combing the PECT effect with the expansions allow for using carbon fibres in an electrochemical cell to harvest energy [5],[6]. Such functionalities could be combined with an inherent electrochemical energy storage (battery function) capability. Imagine a solid-state high-performance structural material that senses its own state, can change shape and harvest energy – that is stored in the material itself!In this work, we will show functionalities coming from alkali ion insertion in carbon fibres that goes beyond the battery function, and how these functions can be combined in a single device. The starting point for these concepts are so called structural batteries, which are hybrid and multifunctional composite materials able to carry load while storing electrical energy like lithium-ion batteries. In such a battery, carbon fibres are used as the load carrying material thanks to their excellent strength and stiffness properties, but also as the active negative electrode. They also include a multifunctional matrix system – a structural battery electrolyte (SBE), the material holding the fibres together to make a solid-state load carrying material, but which at the same time is ionically conductive and chemically stable in the voltage window used. It also includes a multifunctional positive electrode – a composite electrode based on conventional ion inserting materials like lithium iron phosphate (LFP) supported by electrochemically active carbon fibres for load carrying and electrical conduction. This can then also be used for inherent strain sensing in the material without any added mass or wiring. The material can also be made to shape-morph with electrical control at low voltages and harvesting energy by converting mechanical strain to electrical power.

МЕТОДИКА МНОГОКРИТЕРИАЛЬНОЙ СРАВНИТЕЛЬНОЙ ОЦЕНКИ ЭФФЕКТИВНОСТИ ЗАМЕНЫ СРЕДСТВ ИЗМЕРЕНИЙ И АВТОМАТИКИ

Ensuring technological sovereignty requires large-scale and massive replacement of foreign technical means in the control and automation systems of many industrial enterprises. This problem is especially relevant for critical infrastructure facilities, in particular energy supply systems and enterprises. The article presents a methodology that allows for a comparative multi-criteria assessment and selection of control and measuring instruments (measuring-and-recording apparatus) for the comprehensive re-equipment of control and management systems of energy enterprises, heat, electricity and water supply systems, industrial and household consumers. The methodology implements an integrated approach to solving the optimal choice problem based on the Data Envelopment Analysis (DEA) methodology. The global efficiency criterion is formed as a result of the convolution of heterogeneous local efficiency criteria of measuring devices, which makes it possible to take into account specific technological requirements for measuring instruments and methods, the specifics of installation and operating conditions of devices. The method of multi-criteria assessment of the effectiveness of the use of measuring instruments significantly speeds up and simplifies the process of objective selection of optimal technical means and reduces qualification requirements for users. The database and algorithm for calculating global criteria can be used to create a decision support system within the framework of automatic design systems.

Comparison of optimizers for model predictive thermal control of buildings

Considering recent developments in the energy sector, further reduction of electricity cost and flattening of the electric power demand curve are needed. We have focused on an autonomous electric heater control system that can easily be implemented in existing buildings without strict comfort requirements. Examples are winter heating of warehouses and vacation homes, and heat drying of buildings under construction. We have set up a system that typically reduces electricity cost by about 40% on the basis of automatic weather and real time pricing forecasts. The system uses the building as an energy reservoir over periods with high electricity cost. Using a model predictive control system, we compare use of a genetic algorithm, a particle swarm optimization, and a neural network for heater control, all working in a closed loop to reduce the influence of modeling errors. We have simulated the performance of the systems using realistic data and found that all three optimizers give about the same performance, varying only a few percent in efficiency. However, the computational and memory requirements of the neural network are much lower than for the other optimizers, so it is preferable for use with inexpensive microcontrollers. We carried out a full-scale experiment at a residential house and found agreement with simulation results.

Performance analysis of electrical environmental control and ice protection systems in a commercial transport aircraft

PurposeThis paper aims to assess the impact of electrifying the environmental control system (ECS) and ice protection system (IPS), the primary pneumatic system consumers in a conventional commercial transport aircraft, on aircraft weight, range, and fuel consumption.Design/methodology/approachThe case study was carried out on Airbus A321-200 aircraft. Design, modelling and analysis processes were carried out on Pacelab SysArc software. Conventional and electrical ECS and IPS architectures were modelled and analysed considering different temperature profiles.FindingsThe simulation results have shown that the aircraft model with ±270 VDC ECS and IPS architecture is lighter, has a more extended range and has less relative fuel consumption. In addition, the simulation results showed that the maximum range and relative fuel economy of all three aircraft models increased slightly as the temperature increased.Practical implicationsConsidering the findings in this paper, it is seen that the electrification of the conventional pneumatic system in aircraft has positive contributions in terms of weight, power consumption and fuel consumption.Social implicationsThe positive contributions in terms of weight, power consumption and fuel consumption in aircraft will be direct environmental and economic contributions.Originality/valueApart from the conventional ECS and IPS of the aircraft, two electrical architectures, 230 VAC and ±270 VDC, were modelled and analysed. To see the effects of the three models created in different temperature profiles, analyses were done for cold day, ISA standard day and hot day temperature profiles.

Exploitable magnetic anisotropy and half-metallicity controls in multiferroic van der Waals heterostructure

Two-dimensional (2D) XY ferromagnets have drawn pronounced interest in recent years, but the characteristic of easy-plane magnetization restricts their application in spintronics to some extent. Here, we propose a general strategy for constructing multiferroic van der Waals heterostructures, aiming to achieve electrical control over the magnetic anisotropy in 2D XY ferromagnets. The validity of this strategy is verified by the heterostructure composed of ferromagnetic VBi2Te4 and ferroelectric In2Se3 monolayers. By manipulating the polarized states of In2Se3, the VBi2Te4 can be reversibly transformed between 2D XY and Heisenberg ferromagnets, characterized by the switching of easy magnetization axis between in-plane and out-of-plane directions. More interestingly, accompanied by the changes in magnetic anisotropy, the VBi2Te4 also demonstrates a phase transition from a semiconductor to a half-metal state, which can be ascribed to the band alignment and interfacial charge transfer. The switchable magnetic and electronic properties enable the heterostructure to be utilized in nonvolatile memory and logic devices. Additionally, the half-metallicity and magnetocrystalline anisotropy energy of the heterostructure can be effectively tuned by biaxial strain. These findings not only pave the way for electrically nonvolatile control of 2D XY ferromagnet, but also facilitate the development of interfacial magnetoelectric physics and applications.

Electrical and thermal control of Fabry-Pérot cavities mediated by Casimir forces

Electrical and thermal control of Fabry-Pérot cavities mediated by Casimir forces

Electrophysical properties, memristive and resistive switching of charged domain walls in lithium niobate

Charged domain walls (CDWs) in ferroelectric materials raise both fundamental and practical interest due to their electrophysical properties differing from bulk ones. On a microstructure level, CDWs in ferroelectrics are 2D defects separating regions with different spontaneous polarization vector directions. Screening of electric field of the CDW's bound ionic charges by mobile carriers leads to the formation of elongated narrow channels with an elevated conductivity in initially dielectric materials. Controlling the position and inclination angle of CDW relative to the spontaneous polarization direction, one can change its conductivity over a wide range thus providing good opportunities for developing memory devices, including neuromorphic systems. This review describes the state of art in the formation and application of CDWs in single crystal uniaxial ferroelectric lithium niobate (LiNbO3, LN), as resistive and memristive switching devices. The main CDWs formation methods in single crystal and thin-film LN have been described, and modern data have been presented on the electrophysical properties and electrical conductivity control methods of CDWs. Prospects of CDWs application in resistive and memristive switching memory devices have been discussed.