A simple method, based on Machine Learning Radial Basis Functions, RBF, is developed for estimating voltage stability margins in power systems. A reduced set of magnitude and angles of bus voltage phasors is used as input. Observability optimization technique for locating Phasor Measurement Units, PMUs, is applied. A RBF is designed and used for fast calculation of voltage stability margins for online applications with PMUs. The method allows estimating active local and global power margins in normal operation and under contingencies. Optimized placement of PMUs leads to a minimum number of these devices to estimate the margins, but is shown that it is not a matter of PMUs quantity but of PMUs location for decreasing training time or having success in estimation convergence. Compared with previous work, the most significant enhancement is that our RBF learns from PMU data. To test the proposed method, validations in the IEEE 14-bus system and in a real electrical network are done.
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http://dx.doi.org/10.1016/j.heliyon.2019.e02704 | DOI Listing |
J Colloid Interface Sci
January 2025
Engineering Research Center of Advanced Functional Material Manufacturing of Ministry of Education, School of Chemical Engineering, Zhengzhou University, Zhengzhou, 450001 Henan, China; National Key Laboratory of Coking Coal Green Process Research, Zhengzhou University, Zhengzhou 450001, Henan, China. Electronic address:
Hydrogen production via electrocatalytic water splitting has garnered significant attention, due to the growing demand for clean and renewable energy. However, achieving low overpotential and long-term stability of water splitting catalysts at high current densities remains a major challenge. Herein, a CoP@CoNi layered double hydroxide (LDH) electrode was synthesized via a two-step electrodeposition process, demonstrating oxygen evolution reaction, with an overpotential (ƞ) of 373 mV and a Tafel slope of 64.
View Article and Find Full Text PDFJ Physiol
January 2025
Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada.
Here we characterize seven Cx30.3 gene variants (R22H, S26Y, P61R, C86S, E99K, T130M and M190L) clinically associated with the rare skin disorder erythrokeratodermia variabilis et progressiva (EKVP) in tissue-relevant and differentiation-competent rat epidermal keratinocytes (REKs). We found that all variants, when expressed alone or together with wildtype (WT) Cx30.
View Article and Find Full Text PDFNano Lett
January 2025
Shenzhen Institute for Advanced Study, University of Electronic Science and Technology of China, Shenzhen 518110, China.
Efficient oxygen evolution reaction (OER) catalysts with fast kinetics, high efficiency, and stability are essential for scalable green production of hydrogen. The rational design and fabrication of catalysts play a decisive role in their catalytic behavior. This work presents a high-entropy catalyst, FeCoNiCuMo-O, synthesized via carbothermal shock.
View Article and Find Full Text PDFAdv Mater
January 2025
Frontiers Science Center for Flexible Electronics (FSCFE), MIIT Key Laboratory of Flexible Electronics (KLoFE), Northwestern Polytechnical University, Xi'an, 710072, China.
NaV(PO), based on multi-electron reactions between V/V/V, is a promising cathode material for SIBs. However, its practical application is hampered by the inferior conductivity, large barrier of V/V, and stepwise phase transition. Herein, these issues are addressed by constructing a medium-entropy material (NaVTiAlCrMnNi(PO), ME-NVP) with strong ME─O bond and highly occupied Na2 sites.
View Article and Find Full Text PDFMicrosyst Nanoeng
January 2025
Department of Systems Design Engineering, University of Waterloo, Waterloo, ON, N2L 3G1, Canada.
This paper presents a novel technique for low-power generation of frequency combs (FC) over a wide frequency range. It leverages modal interactions between electrical and mechanical resonators in electrostatic NEMS operating in air to provide a simple architecture for FC generators. A biased voltage signal drives the electrical resonator at resonance which is set to match an integer submultiple of twice the mechanical resonator's resonance.
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