Hasil untuk "Electric apparatus and materials. Electric circuits. Electric networks"

Shubham Tyagi, Paresh C. Rout, Shubham Singh et al.

ABSTRACT We investigate the influence of hydrostatic pressure on the physical properties of monolayer FeCl2 for spintronics applications. A phase transition from a ferromagnetic half‐metal to a ferromagnetic semiconductor is unveiled at 4.6 GPa, accompanied by a transition from a non‐polar (1T) to a polar (1H) structure. We demonstrate that hydrostatic pressure elevates the Curie temperature above room temperature (for example, 618 K at 5 GPa) and enhances the magnetic anisotropy energy (for example, 731 μeV per formula unit at 5 GPa). A significant Dzyaloshinskii‐Moriya interaction is present in the 1H structure (due to the broken spatial inversion symmetry) and increases with the hydrostatic pressure. Together with the observation of in‐plane electric polarization (for example, 1.1 pCcm−1 at 5 GPa), this positions the 1H structure as a pioneer in the class of 2D materials. Exploiting the phase transition of monolayer FeCl2, a single‐material magnetic tunnel junction is proposed and an outstanding tunneling magnetoresistance ratio is demonstrated.

Zuchong Yang, Daniele Zucchelli, Melissa Berteau‐Rainville et al.

Abstract Polymer semiconductors hold great potential as active materials in (opto)electronic, thermoelectric, and biomedical devices. Their charge transport performance has seen tremendous progress, with mobilities exceeding 1 cm2 V−1 s−1 for a variety of donor‐acceptor copolymers. Nevertheless, charge injection at the metal/polymer interface is still rather ineffective and poorly understood. In a field‐effect transistor, this process is manifested by the contact resistance (Rc) which, for polymers, is several orders of magnitude higher than for their inorganic counterparts. Therefore, an in‐depth investigation of the charge injection in metal/donor‐acceptor polymer systems is sought‐after. Here, the low‐temperature dependent Rc and charge transport of a model isoindigo donor‐acceptor copolymer‐based transistor are studied. The metal/polymer interface is tuned by functionalizing the electrodes with different thiolated self‐assembled monolayers (SAMs). Rc in devices with SAM‐functionalized electrodes is generally lower and exhibited a weak temperature dependence. Counterintuitively, electrodes functionalized with SAMs expected to lead to an apparently unfavorable energy level alignment displayed the lowest Rc. The Fermi level is found to be pinned at all the encompassed interfaces. An energy‐level alignment modeling is employed to understand this behavior. The findings reveal that simply looking at the energy levels alignment of metal/polymer interface does not necessarily lead to reduced Rc.

Sandra Costanzo, Giovanni Buonanno

This work introduces a probabilistic approach for aperiodic time-modulated arrays tailored to simultaneous multi-beam applications. Specifically, they include on-off RF switches that contribute to amplitude tapering, as in <italic>&#x201C;classic&#x201D;</italic> time-modulated arrays, while the spacing is aperiodic, so it is possible to obtain large distances between the elements, in terms of wavelength, without the appearance of grating lobes. The significant spacing allows also a reduction of the deleterious impact of mutual coupling. The proposed aperiodic time-modulated arrays are broadband in the sense that the carrier frequency can potentially span a wide bandwidth without the appearance of grating lobes, independently on the element placement, and they are high-resolution in the sense that the array aperture can be made <italic>&#x201C;electrically&#x201D;</italic> very large regardless the number of elements. The array factor can be controlled simultaneously and independently via switching timing and element positioning. In addition, the proposed arrays are reconfigurable in the sense that a change in the duty cycles of the switches can relatively easily change the shape of the radiation pattern. Furthermore, the presented mathematical modeling allows for obtaining simultaneous beams.

Juan Pablo Bertucci, Theo Hofman, Mauro Salazar

Electrification of marine transport is a promising solution to reduce sector greenhouse gas emissions and operational costs. However, the large upfront cost of electric vessels and the required charging infrastructure can be a barrier to the development of this technology. Optimization algorithms that jointly design the charging infrastructure and the operation of electric vessels can help to reduce these costs and make these projects viable. In this paper, we present a mixed-integer linear programming optimization framework that jointly schedules ferry operations, charging infrastructure and ship battery size. We analyze our algorithms with the case of the China Zorrilla, the largest electric ferry in the world, which will operate between Buenos Aires and Colonia del Sacramento in 2025. We find that the joint system and operations design can reduce the total costs by 7.8\% compared to a scenario with fixed power limits and no port energy management system.

Yinbo Liu, Haixin Du, Wanting You et al.

Moisture-electric generation (MEG), a technology that captures chemical energy from environmental moisture and converts it into sustainable electricity, has attracted significant attention in the field of flexible wearable electronics. However, existing MEG systems still face critical challenges such as low output voltage, poor current stability, and insufficient mechanical properties of materials. Herein, a poly(acrylic acid) (PAA)/choline chloride (ChCl) eutectogels (PA-C) with a "covalent bond-ion pair-hydrogen bond" triple network structure was prepared via ultraviolet photopolymerization by constructing an acrylic acid (AA)/ChCl deep eutectic solvent (DES). Specifically, the cross-linking agent N,N'-methylenebis(acrylamide) (MBA) forms covalent cross-links with AA to provide a rigid framework for PA-C. Meanwhile, hydrogen bonds between PAA chains, as well as ion pairs and hydrogen bonds between PAA and ChCl, form a reversible physical cross-linking network. These networks synergistically endow PA-C with excellent hydrophilicity and mechanical properties. The effect of the molar ratio of AA to ChCl on the microstructure and properties of PA-C was systematically investigated. The results show that under an appropriate AA/ChCl molar ratio, PA-C exhibits a tensile strength of 4.92 MPa and an elongation at break of 633% simultaneously. The MEG developed based on PA-C achieves a high ionic conductivity of 0.54 S m-1 under relative humidity (RH) of 99%. A single MEG device can deliver an open-circuit voltage (Voc) of 1.28 V and a short-circuit current (Isc) of 2.20 mA, with a maximum power density of 90 μW cm-2. Through series and parallel integration, the voltage and current can be flexibly adjusted, enabling direct power supply to light-emitting diodes (LEDs) and low-power devices. This study not only provides a material system for the design of high-performance MEG devices but also opens up an avenue for the development of efficient, scalable, and flexible multifunctional power sources.

Quanhua Chen, Xiang Wan, Walid Boukhili et al.

Abstract The impact of Al/Ti electrodes on enhancing the performance and operational stability of n‐channel organic electrolyte‐gated transistors (OEGTs) is investigated. Utilizing Al/Ti electrodes as source and drain electrodes in diketopyrrolopyrrole (DPP)‐based polymeric semiconductor OEGTs leads to a significant decrease in the charge injection barrier for electrons, resulting in improvement of all electrical parameters including on‐current, mobility, on‐off ratio, and threshold voltages. Furthermore, through a comparative analysis of transistors utilizing polymer insulators and solid electrolytes as gate dielectrics, the effect of alterations in the electrodes on the contact resistance of each device is examined. In comparison to OEGTs with Au electrodes, OEGTs with Al/Ti electrodes demonstrate higher operational stability following multiple cycling tests. Finally, the OEGTs produced in this study demonstrate reliable short‐term memory characteristics, which are subsequently utilized for reservoir computing, achieving a high recognition accuracy of 94% for spoken digits.

Yuanbo Wang, Jingyan Zhang, Pengwei Dou et al.

Abstract Magnetization switching driven by spin‐orbit torques (SOTs) in perpendicular single magnets contributes to the development of high‐efficiency next‐generation spintronic memory and logic. However, the in‐plane magnetic fields required for deterministic magnetization switching in single magnets hamper the design of all‐electric‐control devices. Herein, a simple, efficient, and reliable all‐electric‐control magnetization switching in a sputtered single L10‐FePt film with an artificial lateral gradient is reported. The deterministic magnetization switching exhibits a strong angle dependence and can be effectively tuned through lateral asymmetry. A maximum self‐switching ratio of 18% is achieved without magnetic fields. The structural characterization results reveal that this deterministic magnetization self‐switching can be primarily attributed to the ordering degree gradient. Furthermore, a programmable Boolean logic device together with a full adder is constructed using the single L10‐FePt magnet. The findings of the study highlight an effective route to accomplish electrical spin manipulation in single magnets. This enables the design of purely electrically controlled SOTs‐based logic and in‐memory computing.

Mohamed Rayane LAKEHAL, Amine MEZENNER, Naouel ARAB et al.

The estimation of plant disease intensity is essential for various purposes, including monitoring epidemics, understanding yield loss, and evaluating treatment effects. Despite the availability of sensor technology to measure disease severity using the visible spectrum or other spectral range imaging, deep learning has emerged as a recent and advanced technique for image processing and data analysis. To enhance the severity estimation in diseased leaves, a CNN ensemble is proposed by fusing deep features extracted from outputs of fully connected layers of various CNN models. A SVM (Support Vector Machine) is utilized to achieve the classification stage. Experiments are carried out on wheat leaf images infected by the Yellow rust disease. Experiments conducted using three CNN models that are VGG16, MobileNetV2 and a customized CNN reveal that the CNN ensemble outperforms individual models.

Bartosz Uniejewski

Accurate day-ahead electricity price forecasts are critical for power system operation and market participation, yet growing renewable penetration and recent crises have caused unprecedented volatility that challenges standard models. This paper revisits variance stabilizing transformations (VSTs) as a preprocessing tool by introducing a novel parametrization of the asinh transformation, systematically analyzing parameter sensitivity and calibration window size, and explicitly testing performance under volatile market regimes. Using data from Germany, Spain, and France over 2015-2024 with two model classes (NARX and LEAR), we show that VSTs substantially reduce forecast errors, with gains of up to 14.6% for LEAR and 8.7% for NARX relative to untransformed benchmarks. The new parametrized asinh consistently outperforms its standard form, while rolling averaging across transformations delivers the most robust improvements, reducing errors by up to 17.7%. Results demonstrate that VSTs are especially valuable in volatile regimes, making them a powerful tool for enhancing electricity price forecasting in today's power markets.

Mohammed Altoumaimi, V. V. Loboda

The present study provides the consideration of a mode III interface crack in one-dimentional (1D) piezoelectric quasicrystal under antiplane phonon and phason loading and inplane electric field. Due to complex function approach all required electromechanical parameters are presented through vector-functions analytic in the whole complex plane except the crack region. The cases of electrically impermeable (insulated) and electrically limited permeable conditions on the crack faces are considered. In the first case a vector Hilbert problem in the complex plane is formulated and solved exactly and in the second one the quadratic equation with respect to the electric flux through the crack region is obtained additionally. Its solution permits to find phonon and phason stresses, displacement jumps (sliding) and also electric characteristics along the material interface. Analytical formulas are also obtained for the corresponding stress intensity factors related to each field. The numerical computations for three selected variants of the loading conditions was conducted and the resulting field distributions are visualised on the crack continuation beyond the crack and also inside of the crack region.

Siddhesh Pimpale

The introduction of Smart Electric Vehicles (SEVs) represents an increasingly disruption on automotive area, once integrates advanced computer and communication technologies to highly electrical cars, which come with high performances, environment friendly and user friendly characteristics . But the increasing complexity of SEVs prompted by greater dependence on interconnected systems, autonomous capabilities and electrification, presents new challenges in cybersecurity as well as functional safety. The safety and reliability of such vehicles is paramount, as unsafe or unreliable operation in either case represents an unacceptable risk in terms of the performance of the vehicle and safety of the passenger. This paper investigates the integrated development of cybersecurity and functional safety for SEVs, emphasizing the requirement for the parallel development of these domains as components that are not treated separately. In SEVs, cybersecurity is quite crucial in order to prevent the threats of hacking, data breaches and unauthorized access to vehicle systems. Functional safety ensures that important vehicle functions (braking, steering, battery control, etc.) keep working even if some part fails. This convergence of functional safety issues with cybersecurity issues is becoming more crucial, since a security incident can result in a failure of catastrophic consequences for a functional safety system and, conversely. This paper reports the current state of cybersecurity and functional safety standards for SEVs, highlighting challenges that include the weaknesses of communication networks, the potential security threats of over-the-air updates, and the demand for real-time responsive systems for failure.

Angel Pan Du, Miguel Arana-Catania, Enric Grustan Gutiérrez

Artificial Intelligence algorithms are introduced in this work as a tool to predict the performance of new chemical compounds as alternative propellants for electric propulsion, focusing on predicting their ionisation characteristics and fragmentation patterns. The chemical properties and structure of the compounds are encoded using a chemical fingerprint, and the training datasets are extracted from the NIST WebBook. The AI-predicted ionisation energy and minimum appearance energy have a mean relative error of 6.87% and 7.99%, respectively, and a predicted ion mass with a 23.89% relative error. In the cases of full mass spectra due to electron ionisation, the predictions have a cosine similarity of 0.6395 and align with the top 10 most similar mass spectra in 78% of instances within a 30 Da range.

A. Lisov, A. Vozmilov

Aim. The analysis of possibilities and prospects of development of an electronic differential system for electric vehicles based on artificial neural networks. Materials and Methods. We discuss the key advantages of the proposed system, such as its customization capability to various vehicle designs, integration of additional sensors, support for self-driving mode and the ability to interact with the ABS system. Results. We considered the ways to improve the model, including the introduction of self-learning algorithms, optimization of inverter circuits for controlling multiple motors, and implementation of all-wheel drive configurations. In addition, we discuss the customization of the electronic differential system for operation on low-power devices using quantization, pruning and architecture simplification methods. Conclusion. The proposed approaches and algorithms have the potential for widespread deployment in the electric vehicle industry, opening new vistas for development of intelligent vehicle control systems.

Catalin-Mihai Popa, D. Gabor, Anamaria Daroczi

The underground and surface mining industry are a complex sector of activity in which the workers involved face difficult working conditions, manifested by high temperatures, high humidity, risks of collapses, explosions and toxic gases, which requires ensuring a high level of occupational safety. In the case of the use of cable networks in underground and surface mining operations, in order to reduce the risk of explosion and increase the level of occupational safety, they must include electrical cables manufactured in accordance with the requirements of specific standards and which must be checked and certified for this purpose. In order to be certified in the voluntary field, power cables intended for use in the underground and surface mining industry must have a robust construction to withstand the mechanical stresses of exploitation, be able to provide appropriate electrical and thermal protection, and be made of materials that prevent the spread of fire.The danger represented by the use in areas endangered by the presence of gray dust of electrical power cables made of poor-quality materials and with an inappropriate construction for the respective environment, is materialized by the possibility of short circuits that generate heat, electric arcs and metal splashes, resulting in the initiation of fires and/or explosions. This paper presents the safety requirements, test methods and test stand for mining electrical cables for their certification in the voluntary field.

S. Kurilin, V. V. Fedotov

The research is aimed at improving the reliability of complex technical systems, including a component such as an asynchronous electric motor, by monitoring their current state. The general objective of the study is to substantiate the possibility of using such a factor as the stator current vector, the oscillations of which are taken as an observable parameter, to diagnose a fault in the mechanical circuit of an electric motor. To substantiate the legitimacy of such a decision, a mathematical modeling apparatus was used with a computational experiment. For this purpose, the purpose and conditions for its implementation were preliminarily formulated, which made it possible to obtain a sufficient evidence base. The mathematical model of an asynchronous electric motor is supplemented with pulse load functions in the form of Fourier series, represented by rectangular alternating and constant sign pulses, the repetition frequency of which is equal to the rotational speed of the electric motor shaft. To conduct a computational experiment, a problem-­oriented algorithm and a Maple program were developed. An original feature of the mathematical model, algorithm and program is the linking of the load torque with the angle of rotation of the rotor, which is typical for damaged mechanical circuits of asynchronous electric motors. Using a mathematical model, the effects on a serial asynchronous electric motor of load torque pulses from a damaged bearing are revealed, as well as the effects of torque pulses from periodic impacts occurring in a damaged mechanical circuit. In both cases, oscillations of the modulus of the stator current vector were recorded, coinciding with the rotor rotation frequency. The results of the computational experiment indicate that stator current fluctuations make it possible to reliably judge the state of the mechanical circuit of the electric motor. The research materials can be used by operating organizations to create systems for instrumental monitoring of the current technical condition of a fleet of asynchronous electric motors.

Tomas Blecha, Martin Hirman, Jiri Navratil

This article deals with the issue of assembling conventional SMD components on textile substrates using UV-curable non-conductive adhesives. This technology is easily applicable in the textile industry. It thus enables the easy and fast production of e-textiles that are equipped with conventional electronic components or even entire electronic modules. The article describes the principle of this innovative technology. Furthermore, comprehensive results of testing the effect of mechanical stress, chemical cleaning, and climatic changes on e-textiles with assembled SMD components on the change in contact resistance are presented here. The results show that this technology can be used for assembling and encapsulating SMD components on a textile substrate in the realization of e-textiles.

Paula Palacios, Abdelrahman M. Askar, Francisco Pasadas et al.

Abstract This work presents a 2D tellurium (Te)‐based diode that exploits the doping achieved by atomic layer deposited (ALD) Al2O3 to enhance its rectifying performance. The proposed device comprises a Schottky junction that is dielectric‐doped to significantly reduce the reverse bias current. A boosted current responsivity four times higher compared to that of undoped devices is achieved, maximizing the performance for radio frequency (RF) power detectors. The application measurement results demonstrate sensitivities as low as −45 dBm, and at −30 dBm RF input power outstanding tangential responsivities up to 6.5 kV W–1, 4.3 kV W–1, and 650 V W–1 at 0.5, 1, and 2.5 GHz, respectively, while reaching linear dynamic range (DR) of over 30 dB. These are the highest reported values for 2D‐based material devices by almost two orders of magnitude. Furthermore, the DR is ≈10 dB larger compared to state‐of‐the‐art power detectors based on bulk semiconductors.

Gerard Deepak, Priti Sharma, S. Jayachitra et al.

Wearable technology can significantly impact human existence by allowing for innovative perspectives on the outside world, such as through the use of augmented reality (AR) programs. Electronic gadgets that are worn as clothing, gadgets, or even incorporated into our bodies are called wearable gadgets. While there are many prospective advantages to smartwatches, their widespread and continuous use raises several privacy problems as well as complex data protection hurdles. Among the newer areas of healthcare informatics involves cognitive computation, which uses biological as well as physical information to autonomously track an individual's emotional status in mobility settings. While effective computation technologies hold great promise for enhancing everyday life, privacy problems and challenges must be addressed before analyzing physical information. Federated knowledge is a viable option for creating high-performing algorithms while protecting people's confidentiality. We used federated training to analyze cardiac activity information that was gathered from smart wristband tracking of anxiety levels during various situations. By protecting the confidentiality of information, we were able to accomplish promising outcomes when implementing federated training in Internet of Things-based wearable physiological tracking devices.

G. Pierrou, C. Valero-De La Flor, G. Hug

In this paper, a novel Energy Management System (EMS) algorithm to achieve optimal Electric Vehicle (EV) charging scheduling at the parking lots of electric railway stations is proposed. The proposed approach uncovers the potential of leveraging EV charging flexibility to prevent overloading in the combined EV charging and railway operation along with renewable generation, railway regenerative capabilities, and energy storage. Specifically, to realize end-user flexibility, each EV state of charge at departure time is introduced as an optimization variable. Peak load constraints are included in the railway EMS to properly adjust EV charging requirements during periods of high railway demand. A comprehensive numerical study using a scenario-tree approach on an actual railway line in Switzerland demonstrates the effectiveness and the feasibility of the proposed method in a practical setting under multiple scenarios.

A. I. Orlov, Il’ya A. Karpov, Vera T. Sidorova

The most common problems of electricity quality in 0.4 kV power transmission lines are voltage deviations and voltage asymmetry, which are clearly manifested at the end sections of long lines with uneven distribution of consumers by phases. The technical means of solving these problems include devices for the uniform distribution of 1-phase consumers across the phases of a 3-phase network based on electromechanical relays, static semiconductor devices and electromagnetic devices. The purpose of the article is to analyze the operation of a symmetrical electromagnetic apparatus consisting of one three-phase winding located on a common magnetic conductor. The scientific novelty consists in determining the operating conditions of a symmetrical electromagnetic apparatus, obtaining qualitative and quantitative characteristics of its operation. The materials and methods. The object of the research is a static electromagnetic apparatus that exhibits properties of voltage and current symmetry when connected to a three-phase unbalanced electric network. The methods of theoretical electrical engineering are used, in particular, the method of symmetric components, including generally accepted methods of analyzing electromagnetic processes in electric machines, methods of mathematical and computer modeling, analysis and generalization. The accepted assumptions are: sinusoidal voltages and currents; the linearity of the magnetization curve of the magnetic core material and the absence of electrical and magnetic losses in the electromagnetic apparatus. The results of the study. It is established that the effect of equalizing currents in the line and voltage symmetry when connecting an electromagnetic device containing one three-phase winding on a common magnetic circuit occurs in the case of simultaneous fulfillment of the conditions: a) the use of a three-phase magnetic circuit in which the zero-sequence magnetic flux cannot be closed in the magnetic circuit; b) connections of transformer windings according to a scheme that allows the flow of zero-sequence currents in linear conductors. The models of the 0.4 kV line with concentrated and distributed load are considered. It is shown that with an asymmetric load, the SEA currents acquire a component of zero sequence, and the linear currents are aligned compared to the load currents. The coefficient of voltage asymmetry of the zero sequence decreases practically to zero, the reverse sequence practically does not change. The effect of voltage symmetry when connecting the SEA occurs both before and after the place of its installation. A decrease in the total losses of electrical energy in the line due to the equalization of currents is demonstrated. Conclusions. An electromagnetic device containing one three-phase winding on a common magnetic circuit has the effect of balancing the voltages and currents of a three-phase power line with a zero wire, if the design of the magnetic wire does not allow the possibility of closing the magnetic flux of zero sequence within its limits, and the winding connection circuit contains a neutral outlet connected to the zero wire of the network, through which zero-sequence currents can flow. The action of the considered electromagnetic apparatus manifests itself in equalizing the line currents in magnitude and, as a result, in reducing the total losses in it. The electromagnetic device symmetrizes the voltages before and after the place of its installation, the greatest effect is manifested when placing the proposed electromagnetic device at the end of the line or at the connection point of the most powerful consumer.