Based on first-principles calculations, the new tetragonal Janus AlSXY monolayers (X,Y = Cl, Br, I; X ≠ Y) are predicted, and the electronic structure, thermoelectric (TE) and piezoelectric properties are also explored. It is found that the system exhibits high electrical conductivity and excellent power factor due to the high carrier mobility in theY-axis direction under n-doping. Notably, the high Grüneisen parameters and low the phonon velocity lead to ultralow lattice thermal conductivity (1.35 W mK-1for AlSClBr, 1.07 W mK-1for AlSClI, and 1.06 W mK-1for AlSBrI). At 700 K, the optimal TE figure of merit reach 4.54 (AlSClBr), 8.27 (AlSClI), and 6.63 (AlSBrI) alongY-direction, surpassing previously reported 2D layered TE materials. Furthermore, the three monolayers show strong piezoelectric responses, where the piezoelectric strain coefficientd31of AlSClI reaches 0.32 pm V-1, indicating the potential applying value in high-performance TE and piezoelectric field.

Donor-acceptor (D-A) conjugated polymers hold significant potential as high-potential thermoelectric (TE) materials due to their adjustable structures, efficient charge transport ability and tunable doping level. However, achieving a balance between the Seebeck coefficient (S) and electrical conductivity (σ) remains challenging. In this work, we employ thienoisoindigo (TIIG) as the acceptor and dithieno[3,2-b:2',3'-d]pyrrole (DTP) as the donor to construct two novel D-A conjugated polymers for TE application. Through introducing thiophene (T) units as spacers between DTP and TIIG, PTIIG-2T-DTP enhances the planarity of conjugated backbones compared to PTIIG-DTP. Moreover, PTIIG-2T-DTP film shows more compact packing between conjugated backbones, which improves the charge transport. Despite slightly lower doping efficiency, doped PTIIG-2T-DTP exhibits superior carrier mobility and conductivity to PTIIG-DTP. Additionally, PTIIG-2T-DTP shows a higher Seebeck coefficient at same doping concentration. Ultimately, PTIIG-2T-DTP achieves a large power factor of 23.2 µWm-1 K-2 with σ of 120 S cm-1 which is much higher than that of PTIIG-DTP. This work develops an effective polymer backbone engineering strategy for developing high-performance D-A conjugated TE polymers.

Highly conductive wet-spun PANI/CNTs fibers for wearable energy harvesting and thermal sensing.

Reactive power market design for unutilized grid-forming assets to address power factor penalties in Turkiye

This study presents a comprehensive multidisciplinary investigation aimed at enhancing the performance of a Savonius vertical axis hydrokinetic turbine by integrating experimental testing, computational fluid dynamics (CFD) analysis employing dynamic mesh model and hybrid optimization through a genetic algorithm integrated machine learning (GA-ML) framework. A novel dual-deflector arrangement is proposed and tested specifically for an elliptical Savonius rotor. The hybrid optimization framework merges the global search efficiency of genetic algorithms with the predictive capabilities of machine learning to identify optimal deflector configurations effectively. The implementation of dynamic meshing enables a realistic representation of the turbine's unsteady rotational motion, thereby enhancing the accuracy and reliability of the simulation predictions. The results of the study show that using two deflector plates with the elliptical shaped Savonius turbine improves the power factor by 30% compared to the conventional Savonius turbine without deflector plates. The Savonius turbine integrated with a novel and optimized channel configuration has been found to be more efficient and suitable and is recommended for power generation from flowing water especially in canals and hydropower farms.

Printing facilitates low-cost thermoelectric generators to power battery-free internet-of-things devices, wearables, and Industry 4.0 systems. However, scaling up requires printable thermoelectric materials with good mechanical properties and high performance. Here, we report a high-performance Ag2(Se1-xSx)1.05-based n-type printed thermoelectric film through a combination of engineering non-stoichiometric defects and sulfur substitution. An optimal sulfur substitution of 2 at. % facilitates an excellent flexibility and a power factor of~16 µWcm−1 K−2 at 360 K, a 65 % increase compared to a pristine Ag2Se film. A fully printed origami-thermoelectric generator produces a maximum power output {P}_{max } of 907 µW at a temperature difference of 80 K. A record-high power density pd of 21 W m−2 (corresponding to 800 µW g−1 as a weight-normalized power density) is achieved, twice that of previously reported origami-thermoelectric generators. These results highlight cost-effective manufacturing of thermoelectric generators with the capability to power next-generation autonomous electronic devices.

A unified dq-frame-based control strategy for a three-phase grid-connected photovoltaic (PV) inverter that serves as a flexible power-conditioning device is presented in this study. The proposed technique enables a multifunctional inverter design to simultaneously inject active power, reduce harmonic current, and compensate for reactive power. This differs from earlier systems that required multi-conversion structures or independent active power filters. The method is governed by the synchronous reference frame. It uses the DC link's instantaneous power balance to regulate the flow of bidirectional active power when there is either too much or too little PV power. The load current is divided into its basic and oscillating components using the dq-frame instantaneous power representation. Because of this, it can handle loads that are not straight lines or that combine curves and straight lines. Only the reactive and harmonic currents fluctuate, and the grid interface's unity power factor. The proposed approach has been tested under a wide range of conditions, including nonlinear, capacitive, and inductive loading. The findings demonstrate that regardless of how the system is configured, the grid current remains sinusoidal and in sync with the grid voltage. Additionally, the inverter side has very little harmonic distortion. These findings demonstrate that adding features that directly enhance the power quality of grid-connected PV inverters is simple and efficient with the suggested control framework.

Abstract Soil security underpins sustainable agriculture and land restoration in sub-Saharan Africa, yet empirical evidence on what shapes farmers’ understanding of it remains limited. This study investigates the socioeconomic and institutional factors influencing soil-security awareness and perceived importance among 667 smallholder farmers in Ghana. It represents the first empirical application of the McBratney five-dimension framework to analyze farmers’ cognitive understanding of soil security in Africa. Using hierarchical logistic regression, linear regression, and structural-equation modeling, we examined the effects of education, agricultural-extension access, regional location, and workshop participation. Results show that 63% of farmers were aware of soil security, rating its importance highly at 4.01 out of 5 (SD = 1.14). Education emerged as the most powerful factor, substantially increasing both the likelihood of awareness (OR = 2.95, 95% CI [1.82, 4.93]) and importance ratings (β = 0.66, 95% CI [0.45, 0.86]), likely reflecting enhanced information access and cognitive framing. Access to extension services and workshop attendance also significantly improved awareness, underscoring their policy relevance. Mediation analysis indicated that extension contact accounted for approximately 4% of education’s total effect on awareness. Regional disparities were notable: farmers in the Northeast region had 75% lower odds of awareness than those in Ashanti, possibly reflecting infrastructural and institutional limitations. Awareness concentrated on practical dimensions such as Condition (37.9%) and Capital (29.7%), while institutional (Codification 4.6%) and ecological (Capability 3.1%) aspects were least recognized. Policies combining education with participatory extension and training can strengthen soil-security stewardship among Ghanaian smallholders.

This study investigated the fault ride through capability of inverter-based resources in weak distribution networks and proposes a fault-oriented reactive power compensation strategy using only point of common coupling voltage measurements. The proposed strategy determines the reactive power command based on the minimum phase voltage, which represents the most severely depressed phase during unbalanced faults, without fault type detection or sequence component analysis. As a result, the same control framework can be applied to single-line-to-ground, double-line-to-ground, and three-phase faults. A detailed MATLAB/Simulink model of a Korean distribution feeder was developed using actual system parameters. The proposed strategy was compared with a no control case and a conservative fixed capacity reactive power injection scheme derived from commonly adopted power factor limits. Simulation results show that the no control case provides no voltage support, while the fixed capacity approach yields limited improvement in weak grids. In contrast, the proposed strategy maintains stable inverter operation and improves voltage recovery. At locations with an extremely low weighted short circuit ratio of 0.303, the proposed strategy prevents inverter tripping during temporary faults and satisfies low voltage ride through requirements, demonstrating its practical effectiveness.

ABSTRACT Organic thermoelectric materials are promising for flexible waste‐heat recovery, yet their inherently low electrical conductivity restricts practical use. Here, we demonstrate significant performance enhancement via chemical doping of PJ71 conjugated polymer‐wrapped single‐walled carbon nanotubes (SWCNTs). The donor‐acceptor polymer PJ71 effectively disperses SWCNTs while preserving their intrinsic electrical characteristics, achieving optimal performance at 50 wt.% SWCNT loading with conductivity (σ ) = 386 S cm −1 and Seebeck coefficient ( S ) = 33 µV K −1 . Chemical doping with tris(pentafluorophenyl)borane (BCF) through a Brønsted acid mechanism boosts σ to 1196 S cm −1 while retaining S = 26 ± 2 µV K −1 . The optimized composite exhibits a peak power factor of 125 µW m −1 K −2 at 434 K, approximately twice that of the undoped film. Flexible thermoelectric generators fabricated from these materials deliver 20 mV open‐circuit voltage at ΔT = 100 K and maintain stable output over 500 bending cycles. These results establish an efficient molecular‐doping strategy for scalable, high‐performance organic thermoelectrics suitable for flexible energy harvesting.

The increasing demand for high-power electric vehicle charging systems with Vehicle-to-Grid (V2G) capability highlights the need for modular, scalable power converters. This paper proposes a hierarchical control strategy for a high-power, multi-port electric vehicle charging station. The system, based on a Series-Parallel Modular Multilevel Converter (SP-MMC) with isolated modules, is managed by a coordinated control strategy that integrates proportional-integral-resonant regulators, nearest-level control with voltage sorting, and single-phase-shifted modulation. The proposed system enables simultaneous, independent regulation of multiple bidirectional, isolated direct current ports while maintaining grid-side power quality and internal variables of the SP-MMC. The proposed control is validated using real-time Model-In-the-Loop (MIL) simulations that include sequential port activation, bidirectional power flow, and charging operation. MIL results demonstrate stable operation with controlled DC-link voltage ripple, accurate per-port current tracking, and near-unity grid power factor under multi-port operation.

The integration of high-penetration renewable energy sources (RESs) and electric vehicles (EVs) increases the risk of voltage fluctuations in distribution networks. Traditional static partitioning strategies struggle to handle the intermittency of wind turbine (WT) and photovoltaic (PV) generation, as well as the spatiotemporal randomness of EV loads. Furthermore, existing scheduling methods typically optimize EV active power or reactive compensation independently, missing opportunities for synergistic regulation. The main novelty of this paper lies in proposing a spatiotemporally coupled voltage-stability optimization framework. This framework, based on an hourly updated electrical distance matrix that accounts for RES uncertainty and EV spatiotemporal transfer characteristics, enables hourly dynamic network partitioning. Simultaneously, coordinated active–reactive optimization control of EVs is achieved by regulating the power factor angle of three-phase six-pulse bidirectional chargers. The framework is embedded within a hierarchical model predictive control (MPC) architecture, where the upper layer performs hourly dynamic partition updates and the lower layer executes a five-minute rolling dispatch for EVs. Simulations conducted on a modified IEEE 33-bus system demonstrate that, compared to uncoordinated charging, the proposed method reduces total daily network losses by 4991.3 kW, corresponding to a decrease of 3.9%. Furthermore, it markedly shrinks the low-voltage area and generally raises node voltages throughout the day. The method effectively enhances voltage uniformity, reduces network losses, and improves renewable energy accommodation capability.

We present a first-principles investigation of the combined effects of chemical doping and nanostructuring on the thermoelectric performance of the double halide perovskite Cs 2 NaYbCl 6 . Using density functional theory and Boltzmann transport calculations, we explicitly include all relevant scattering mechanisms (namely, electron–phonon, phonon–phonon, Coulomb impurity, phonon–impurity, and grain boundary scattering) to evaluate electrical and thermal transport coefficients. Our results show that Coulomb scattering from dopants is strongly screened and negligible compared to dominant electron–phonon interactions. Thus, both n - and p -type doping enhance electrical conductivity while only moderately reducing the Seebeck coefficient, leading to a significant increase in power factor. Phonon–impurity scattering is found to be minimal, while grain boundary scattering effectively reduces lattice thermal conductivity without strongly affecting carrier mobility. Combining optimal n -type doping ( 10 19 cm − 3 ) with nanoscale grains (10 nm), the figure of merit Z T increases from ∼ 10 − 8 in the pristine crystal to ∼ 0.12 . These findings demonstrate a viable pathway for improving thermoelectric efficiency in wide-band-gap, lead-free perovskites through controlled extrinsic modifications.

Aviation power systems require extremely high reliability. As a result, rectifiers must be capable of continuing operation during phase-lack faults, where the input voltage of one phase drops to zero. However, traditional fault-tolerant strategies often struggle to maintain effective control under these conditions. To address this issue, this paper proposes a single-phase control strategy specifically designed for the Vienna rectifier, a commonly used component in aerospace power systems. This strategy ensures a stable DC output during phase-lack faults while maintaining low total harmonic distortion and a near-unity power factor. Simulation results confirm the effectiveness of the proposed control method.

The aim of the project is to develop a buck-boost converter that improves the input power factor of AC power supplied by activating the AC input current waveform. Themain functionality of the project is to provide a near unity power factor for the buck-boost operation and reduce the total harmonic distortion. Due to increase in the use of converters in industries and home, low power factor conversion results inhuge losses of power. To fill this gap, a near unity power factor is designed for the buck boost operation. The project will solve the problems of manual monitoring and provides a platform to perform actions without the presence of user near thehydroponics system. For PFC BBC, the suggested control methodology utilizes a Proportional-Integral (PI) controller in the outer voltage loop and an Inductor Average Current Mode Control (IACMC) controller in the inner current loop. TheIACMC has several advantages, including its robustness when line voltage and output load fluctuate significantly. The PI controller is designed using the BBC's state space average concept. MATLAB/Simulink is used to simulate the proposedsystem and its control circuit. The simulation findings indicate that a power factor close to unity can be achieved and that there is virtually no change in power factor when a different duty cycle is applied.

This article introduces an extensive directional relaying algorithm designed for series-compensated transmission lines. The proposed algorithm relies on observing the locus of the calculated impedance of the change of the positive-sequence circuit. Both the voltage and current signals in positive sequence circuit are observed to acquire the impedance perceived by the relay. The fault direction is identified by the quadrant in which the locus of the obtained impedance settles. The proposed algorithm is distinguished by its high performance under varying prefault power factor and active power flow direction. It is tested for a range of fault types, varying fault resistance values, diverse fault locations, and different compensation ratios. All tests have been conducted while considering the nonlinear behaviour of the shunt metal oxide varistor (MOV) with the series-compensation capacitor. Furthermore, the proposed scheme is validated with a T-connected multi-terminal Egyptian transmission system. It is extensively tested and compared with other relevant schemes in the literature.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-33564-9.

This study aims to assess the energy efficiency of LED luminaires used in public road lighting by comparing manufacturer-declared photometric and electrical parameters with laboratory simulation results. The research also evaluates the performance of these luminaires across various road types and installation configurations to determine compliance with national and international standards. Eleven LED luminaires were tested using a rotating mirror goniophotometer in an ISO/IEC 17025-accredited laboratory. Simulations were conducted using Dialux Evo software across six road types (M1–M6) and three installation configurations (unilateral, bilateral, and staggered). Key parameters analyzed included brog (Lm), overall uniformity (U0), longitudinal uniformity (Ul), luminous efficacy (lm/W), power factor, and total harmonic distortion (THD) in voltage and current. Discrepancies were found between manufacturer-declared and simulation results, especially in higher-class roads (M1–M3), where up to 28.57% of luminaires failed to meet the minimum luminance requirements when tested. The study highlights the importance of validating manufacturer specifications through accredited laboratory testing. Overall, LED technology improves energy efficiency in public lighting, and inconsistencies in the power factor and luminance performance suggest the need for stricter regulatory oversight and more rigorous quality control. Simulation tools like Dialux Evo prove essential for optimizing lighting designs tailored to specific road types and traffic conditions.

Coal mine ventilation systems face coupled and systemic risks characterized by structural interconnection and disaster chain propagation. In order to accurately quantify and evaluate this overall system risk, this study presents a new method of risk assessment of the coal mine ventilation system based on fuzzy polymorphic Bayesian networks. This method effectively addresses the shortcomings of traditional assessment approaches in the probabilistic quantification of risk. A Bayesian network with 44 nodes was established from five dimensions: ventilation power, ventilation network, ventilation facilities, human and management factors, and work environment. The risk states were divided into multiple states based on the As Low As Reasonably Practicable (ALARP) metric. The probabilities of evaluation-type root nodes were calculated using fuzzy evaluation, and the subjective bias was corrected by introducing a reliability coefficient. The concept of distance compensation is proposed to flexibly calculate the probabilities of quantitative-type root nodes. Through the verification of the ventilation system of H Coal Mine in Shanxi, China, it is concluded that the high risk of the ventilation system is 18%, and the high-risk probability of the ventilation system caused by the external air leakage of the mine is the largest. The evaluation results are consistent with real-world conditions. The results can provide a reference for improving the safety of the ventilation systems.

The conventional full power converter (FPC) for battery energy storage applications is limited by bulky components and suboptimal efficiency. In response, a series-connected step-up/down partial power converter (SUDPPC) with high power density is proposed in this paper. It consists of an LLC resonant converter operating at a fixed switching frequency cascaded with a full-bridge converter capable of providing bipolar output. By connecting the SUDPPC in series with the load, the voltage stress on the series side and the current stress on the parallel side are markedly reduced. The four-quadrant function provides support for further optimization of the rated power level. Universal series interconnection schemes are elaborated, and design guidelines are formulated based on power distribution characteristics. Furthermore, the topology is evaluated in terms of nonactive power and component stress factor (CSF), and benchmarked against a four-switch buck/boost FPC and a phase-shifted full-bridge step-up partial power converter (SUPPC). Finally, a 1.1kW prototype is developed to experimentally validate the theoretical analysis, demonstrating that only 14.3% of the total active power is processed under full-load conditions, with a peak efficiency of 98.15%.

Exploiting the atomistic tight-binding theory with the sp-d exchange term, the electronic and magnetic characteristics of CdSe nanoparticles embedded with Mn, Fe and Co are determined as a function of external magnetic fields to realize the sp-d exchange interactions. The transition metal species and applied magnetic fields are powerful factors to manipulate the electronic and magnetic characteristics of doped CdSe nanoparticles. With growing applied fields, the energies of spin splitting, Zeeman splitting and magnetic polaron improve and are assumed to reach saturation at high fields. All g-factor values are boosted in the presence of the external field and then fade with increasing applied fields. The electron spin-splitting energies and electron g values are ordered as Fe:CdSe > Mn:CdSe > Co:CdSe. The single-particle gaps, hole spin-splitting energies, Zeeman splitting energies and hole g values follow the order Co:CdSe > Fe:CdSe > Mn:CdSe.